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Convert photos to Atkinson dithering

https://gazs.github.io/canvas-atkinson-dither/
136•nvahalik•2h ago•23 comments

Bill Atkinson has died

https://daringfireball.net/linked/2025/06/07/bill-atkinson-rip
824•romanhn•6h ago•165 comments

BorgBackup 2 has no server-side append-only anymore

https://github.com/borgbackup/borg/pull/8798
90•jaegerma•4h ago•54 comments

Self-Host and Tech Independence: The Joy of Building Your Own

https://www.ssp.sh/blog/self-host-self-independence/
86•articsputnik•5h ago•17 comments

Joining Apple Computer

https://www.folklore.org/Joining_Apple_Computer.html
16•tosh•2h ago•0 comments

You need much less memory than time

https://blog.computationalcomplexity.org/2025/02/you-need-much-less-memory-than-time.html
33•jonbaer•1h ago•5 comments

My experiment living in a tent in Hong Kong's jungle

https://corentin.trebaol.com/Blog/8.+The+Homelessness+Experiment
109•5mv2•6h ago•44 comments

Discovering a JDK Race Condition, and Debugging It in 30 Minutes with Fray

https://aoli.al/blogs/jdk-bug/
37•aoli-al•4h ago•7 comments

What was Radiant AI, anyway?

https://blog.paavo.me/radiant-ai/
140•paavohtl•9h ago•82 comments

Updates to Advanced Voice Mode for paid users

https://help.openai.com/en/articles/6825453-chatgpt-release-notes
23•mfiguiere•2h ago•16 comments

Math Symbol Frequencies

https://leancrew.com/all-this/2025/06/math-symbol-frequencies/
11•tosh•2h ago•1 comments

Washington Post's Privacy Tip: Stop Using Chrome, Delete Meta Apps (and Yandex)

https://tech.slashdot.org/story/25/06/07/035249/washington-posts-privacy-tip-stop-using-chrome-delete-metas-apps-and-yandex
231•miles•6h ago•123 comments

The time bomb in the tax code that's fueling mass tech layoffs

https://qz.com/tech-layoffs-tax-code-trump-section-174-microsoft-meta-1851783502
1276•booleanbetrayal•3d ago•791 comments

Low-Level Optimization with Zig

https://alloc.dev/2025/06/07/zig_optimization
228•Retro_Dev•15h ago•106 comments

Why We're Moving on from Nix

https://blog.railway.com/p/introducing-railpack
186•mooreds•11h ago•82 comments

Hate Radio (2011)

https://rwandanstories.org/genocide/hate_radio.html
123•thomassmith65•8h ago•101 comments

OneText (YC W23) Is Hiring a DevOps/DBA Lead Engineer

https://jobs.ashbyhq.com/one-text/b95952a2-9bc2-4c3a-9da1-3dcc157b4a27
1•bluepnume•6h ago

A tool for burning visible pictures on a compact disc surface

https://github.com/arduinocelentano/cdimage
123•carlesfe•14h ago•44 comments

Researchers develop ‘transparent paper’ as alternative to plastics

https://japannews.yomiuri.co.jp/science-nature/technology/20250605-259501/
367•anigbrowl•1d ago•229 comments

Field Notes from Shipping Real Code with Claude

https://diwank.space/field-notes-from-shipping-real-code-with-claude
22•diwank•5h ago•1 comments

Getting Past Procrastination

https://spectrum.ieee.org/getting-past-procastination
277•WaitWaitWha•20h ago•128 comments

The FAIR Package Manager: Decentralized WordPress infrastructure

https://joost.blog/path-forward-for-wordpress/
177•twapi•18h ago•43 comments

Musk-Trump dispute includes threats to SpaceX contracts

https://spacenews.com/musk-trump-dispute-includes-threats-to-spacex-contracts/
128•rbanffy•9h ago•224 comments

How we decreased GitLab repo backup times from 48 hours to 41 minutes

https://about.gitlab.com/blog/2025/06/05/how-we-decreased-gitlab-repo-backup-times-from-48-hours-to-41-minutes/
506•immortaljoe•1d ago•215 comments

PyOpticL – Code-to-CAD optical system engineering

https://github.com/UMassIonTrappers/PyOpticL
14•cinquemb•6h ago•1 comments

I read all of Cloudflare's Claude-generated commits

https://www.maxemitchell.com/writings/i-read-all-of-cloudflares-claude-generated-commits/
201•maxemitchell•1d ago•197 comments

A year of funded FreeBSD development

https://www.daemonology.net/blog/2025-06-06-A-year-of-funded-FreeBSD.html
336•cperciva•1d ago•110 comments

Why are smokestacks so tall?

https://practical.engineering/blog/2025/6/3/why-are-smokestacks-so-tall
159•azeemba•22h ago•42 comments

If it works, it's not AI: a commercial look at AI startups (1999)

https://dspace.mit.edu/handle/1721.1/80558
98•rbanffy•9h ago•52 comments

The Illusion of Thinking: Understanding the Limitations of Reasoning LLMs [pdf]

https://ml-site.cdn-apple.com/papers/the-illusion-of-thinking.pdf
316•amrrs•1d ago•175 comments
Open in hackernews

I'm Wirecutter's water-quality expert. I don't filter my water

https://www.nytimes.com/wirecutter/reviews/know-your-water-quality/
64•rufus_foreman•5h ago

Comments

madaxe_again•5h ago
People are really funny about water. Recently had family visit us in Portugal, and they refused to drink the tap water anywhere - despite it being an EU country and complying with relevant standards, rigorously.

Then again, they also refused to drink our water at home, which I know is nothing but H2O, as we live off grid and it all goes through numerous filters before hitting the RO.

Then again, where they live (and drink the tap water), I also drink the tap water, because again, EU, safe - but it tastes like a swimming pool, as they dose it heavily with chlorine.

Each to their own.

mig39•5h ago
In Portugal, I tend to fill a big jug with tap water (which I know is safe, I watched them put in the treatment plant!), but then leave it in the fridge. After a bit of time, the chlorine just evaporates. So it's nice and cool.
madaxe_again•3h ago
The chlorine in the water is still there, but yes, the free chlorine (which is what you smell/taste) dissipates fairly quickly once it isn’t contained.
ajb•5h ago
My parents drink tap water, but every morning my father would pour away a few liters of water in case the supply pipe was made of lead and the water sitting in it overnight had absorbed some. (This is actually the official government advice in the UK, if your house is older than 1970. Of course, the better option is to replace it with non lead, if you can.)
vsskanth•5h ago
It's mostly for taste at this point, rather than safety. For a long time I used to drink right from the tap, now use a filter pitcher simply because it tastes better.
Crye•5h ago
does it taste better because of temperature, aeration?
lagniappe•5h ago
lower TDS, less chlorine smell
thrill•3h ago
Far less of everything that is bigger than a water molecule.
s0rce•1h ago
Are you filtering your water with molecular sieves? Most water treatment doesn't work by size.
torqueehmada•2h ago
Not the person you asked, but the chlorine level is very high in my muni water so I like running it through a Britta charcoal filter. If I'm in a rush, tap is fine.
scotty79•5h ago
where can I check how much PFAS my local water in EU contains?
tetris11•5h ago
https://foreverpollution.eu/map/

It's not as good as the US's one though

https://www.ewg.org/interactive-maps/pfas_contamination/map/

constantcrying•1h ago
You should look at the website of your local water distributor, mine has very local measurements about the tap water.
username223•5h ago
The fact that potable water is so cheap in the developed world that you can use a gallon of it to flush your toilet is a miracle of civilization. Filter it if that makes you feel better, but it's a waste of money, and a dismissal of a major achievement in public health.

But hey, at least it's not bottled water, which is basically tap water that has been put in a single-use plastic bottle and trucked across the country.

jasoncartwright•4h ago
Tangential! I bought a 210L water butt to collect rainwater to water plants a while back. It cost £110 to my door with the all installation parts. Out of interest I looked up that the cost to fill it with pristine London tap water would be ~52p. 211 uses and I'm at breakeven, money-wise.
formerly_proven•4h ago
https://imgflip.com/i/2htzm9
donnachangstein•4h ago
> But hey, at least it's not bottled water, which is basically tap water that has been put in a single-use plastic bottle and trucked across the country.

Everyone acts like bottled water is evil until there is a water crisis, then it's the lifeline.

username223•2h ago
I don't understand your point. That $8/gal water next to the Starbucks checkout is not addressing a crisis when the baristas are rinsing out people's cups with equivalent water for free. The bottled water isn't next to the prepper-sized cans of dehydrated food in your supermarket.
ghostly_s•5h ago
Wirecutter "expert" doesn't hold much sway for me with the quality of their reviews these days.
aprilthird2021•4h ago
Wirecutter is just a worse version of Consumer Reports where they don't guarantee they aren't running ads and accepting money from the retailers whose products are featured in the media
fossuser•4h ago
It's even worse than that - they have the same anti-tech political bent as the rest of the legacy tech press. Thankfully we have better options now.
righthand•4h ago
Question: Is there some implied negative critique of Consumer Reports here? I rather enjoy their work and the fact they're reader funded, but I wouldn't be surprised if there's something I should be aware of that's not clear from it (the way they test or how they accept another type of money). I know they review too many cars (every issue lately features a car banner at the top of the cover).
brookst•2h ago
Not the person you asked, but I find consumer reports useless because they typically conflate functional evaluation (does the product do what it’s supposed to) with non-functional factors (warranty, price) in a one-size-fits-all manner.

If I’m shopping for a hand mixer, I want to get a list of the best ones and then make my own call on price / performance. I don’t want to be told a $19 product is the best and have to carefully dissect the article to learn that it’s not actually the best, CR has just decided on my behalf that the actual best product isn’t worth $10 more.

rufus_foreman•2h ago
So what review site would you go to if you're shopping for a hand mixer, or is there no such animal?
torqueehmada•2h ago
Incoming anecdata:

I'm in my 50's and consult consumer reports whenever I need to buy a white-box appliance. I've moved a few times so I find myself having to do this more than most people.

The qualm I have with CR goes back to the 1980's when I was a bike mechanic for many years. I had a broad knowledge of all the current brands, and knew which bikes were cheap junk. CR had incorrectly ranked the quality of the bicycles largely due to how they "felt" while riding them. One bike, which was actually good quality, got dinged because it wasn't adjusted properly ("Shifter did not engage lowest gears." or something like that). That one article tainted my opinion of them for anything that requires "tuning" by an expert.

YMMV. Mine has for 40 years. :)

righthand•2h ago
Thank you that is very informative in the context as I'm rather new to Consumer Reports. There definitely articles strange rankings. For example I was looking for an reverse osmosis filter and this is something consumer reports just doesn't really have ranked (at least no searchable from their website). They have 1-2 models and they're both not brands that match "reddit reverse osmosis filter" when I do a web search.

I do enjoy their studies on things like: the percentage of plastic particles in General Mills products.

aerostable_slug•1h ago
> they review too many cars

What do you mean by that? Do think they review new cars they shouldn't?

Also, I suspect they may have found that they attract many new subscribers from people researching car purchases, so it makes sense to have fresh content on the subject to ensure those new eyeballs find value in the publication and decide it might be for them in the long term.

bobxmax•2h ago
If I need something I usually just buy what Wirecutters recommends and I'm rarely disappointed.
Uehreka•4h ago
I love this guy’s review of the Molekule air purifier where he rips it to shreds while detailing his methodology. If nothing else, I definitely trust this guy.
BugsJustFindMe•5h ago
Money quote:

> readings of PFAS that exceed EPA limits have been found in just 8% of small public water systems (those that serve fewer than 10,000 people) and 15% of large ones

15%!

Anyone who trusts their municipal water supply because of *handwave* regulations and reports needs to read that again.

Even if my water were 100% pristine as the author's apparently is, which they only know for their own homes because they've tested it at their taps half a dozen times with different laboratories, my tap water still tastes awful, and maintaining a dedicated three stage filter spout next to my kitchen faucet costs me approximately nothing and provides substantially better tasting water. And I don't need to worry about whether I live in the next Flint, Michigan.

It took two whole years for administrators in Flint, Michigan to acknowledge their lead pipe crisis. What your treatment plant claims it does and what your municipal government claims your safety profile is do not matter one bit if you aren't constantly testing the water actually coming out of your taps.

I'd rather just filter my water. It's much less hassle and I get better tasting water as a nice bonus.

timr•4h ago
I'm failing to see your point. If you think it helps -- whether because of taste or personal trust issues or something else -- then great, filter your water. You do you.

The article is clearly for someone who is otherwise on the fence and doesn't have those issues.

BugsJustFindMe•3h ago
> I'm failing to see your point

That's weird because I'm pretty sure that my point is explicitly spelled out. But just in case, here it is again:

If your trust is based in municipal numbers or statements, you should be aware that municipal numbers and statements are not trustworthy because there's a lot of widespread decaying infrastructure (and coverup!) between where they test, what they make public, and where your water comes out of your faucet.

And if your trust is based on "Rah, rah, America!", you should know that 15% (!!) of water systems serving over 10k people have PFAS levels measured above what the EPA says is safe. (And if you don't think that 15% is a lot, holy smokes, that's nuts.)

So if you aren't testing your tap constantly then you have no idea what your water is like, no matter what the city says their water is like.

And if you are testing your taps constantly, it's less hassle and gives a better result to just filter your water instead.

The author says "I don't filter because I constantly test my taps and they're good each time." That's not the same at all as saying that filtering isn't a generally good idea, especially for anyone who isn't constantly testing their taps. The author ALSO says "a fuckton of you have more PFAS in your water than the EPA says is safe, just not me, lol". The author also chooses to ignore that their good water today may become bad tomorrow.

rufus_foreman•3h ago
>> municipal numbers and statements are not trustworthy

The claims of the manufacturers of filters, of course, are completely trustworthy. If you aren't testing the capabilities of your filters constantly, this is fine.

BugsJustFindMe•2h ago
You can sue a manufacturer for lying about independent testing and certification. Good luck suing your county.
rufus_foreman•2h ago
If you win the lawsuit against the manufacturer, do you get your health back?
Xss3•1h ago
The point is they have a reputation to uphold and not just skin in the game but multiple peoples livelihoods.

Just one or two bad test results, or one failed audit, can sink a business like that.

The county can have thousands of people scream for years (flint, Michigan) without panicking.

mousethatroared•1h ago
I don't trust the manufacturer, but I can test the manufacturers water.

I don't trust my municipality because they cheaped out on the corrosion inhibitors chemistry, leached lead into the water and my house is now filled with developing pinhole leaks. I've had five in four years.

Hint, I don't live anywhere near Flint MI.

jay_kyburz•1h ago
Do you test your water after its been through the filters? I'd have some concerns about putting my trust in some random filter company.
SvenL•1h ago
And to that extend do you trust the company creating the test kit? Or their suppliers?
donnachangstein•4h ago
> and maintaining a dedicated three stage filter spout next to my kitchen faucet costs me approximately nothing

Calling bullshit on this one. I have one, it's positively wonderful, but the filters are expensive and per the manufacturer's recommendation you're supposed to change them all simultaneously. So when one times out, they all time out. This runs approximately $150 a year minimum depending on usage.

BugsJustFindMe•3h ago
> This runs approximately $150 a year

$150 per YEAR at american prices is approximately nothing. That's a measly 41 cents a day.

People spend far far more than that on far far more frivolous things without thinking twice.

EA-3167•3h ago
People spend an order of magnitude (and much more) on coffee every day, never mind smokers or drinkers who spend crazy amounts just to hurt themselves.

Not that I don't love and respect Wirecutter (I don't), but I'm on team "I like how my water tastes when it's filtered."

kelnos•3h ago
I suspect for most people posting here, $150 per year is "approximately nothing".
tguvot•2h ago
filters are cheap if you don't use fancy branded system that came up with it's own filter that incompatible with anything else
an_aparallel•1h ago
You generally want to avoid cheap filters as they apparently can be tainted with formaldehyde
bernawil•2h ago
> So when one times out, they all time out

Some units give you different fixed timespans for each. For that reason, I just use the Reverse Osmosis stage and ignore the rest. RO is the last step, and in theory it renders pure water meaning the only reason to have the previous ones is to pre-filter somewhat the water and extend the RO cartridge lifespan. Problem with that is, first, there's no way to gauge when each filter is spent. Second, they're priced the same anyway, so why even bother. Just go straight from tap to RO! Keep the post re-mineralization stage if you want.

tguvot•1h ago
pre-filters typically have specified "capacity" in gallons. which is measurable. also if water is very dirty filters get clogged and pressure dropped. it's also measurable.

"post re-mineralization stage" is actually "ph adjustment".

Xss3•1h ago
It isnt merely ph adjustment... You want some amount of minerals in water for your health, plants, and taste. Changing the PH isnt the concern in most cases, its just part of the result.
mousethatroared•1h ago
Food gives you all the minerals you need. Matter of fact food can cover most of your hydration needs.
mousethatroared•1h ago
What system are you using? My five stage filter system has me replace the charcoal filters once a year and the RO every... three? Maybe five?

But let's assume it costs you $150 a year. Thats less than $0.50 a day for drinking and cooking water. I doubt you could buy any significant amount of bottled water for fifty cents.

zahlman•3h ago
> three stage filter spout

... But does it remove the PFAs?

BugsJustFindMe•3h ago
You can read the independent test data sheet: https://www.brondell.com/content/UC300_Coral_PDS.pdf

But if you want a full RO system, go for it. They cost only slightly more and just take up more room under the sink.

OptionOfT•3h ago
Your filter system is not set up for water that is microbiologically unsafe to drink.

And if that filter setup also has an RO system your cost is more, as with RO you have a certain amount of rejection rate.

tguvot•2h ago
last time i made calculation, it was still cheaper than bottled water
mousethatroared•2h ago
I trust my municipality to give me microbiologically safe water.

Because I trust bleach, not my local water authority.

I certainly do not trust them to give me chemically clean water. So I have a $150 under-sink RO system.

bilsbie•2h ago
Is there a chance it can get contaminated with bacteria? I worry about the water sitting in there.
Xss3•1h ago
A properly working RO system will prevent viruses and bacteria from passing. For the extra paranoid you can get systems with a UV sterilisation step.
Xss3•1h ago
Just to add, most municipalities chlorinate the water slightly, so its highly unlikely youll find anything alive in it.

My water is fairly heavily chlorinated where i live compared to my previous county.

Letting the glass of water sit in open for a few minutes after pouring helps with taste because the chlorine evaporates.

vel0city•46m ago
If you have a lot of chlorine taste just having a pitcher in the fridge will nearly eliminate the chlorine taste.
mousethatroared•1h ago
I've thought about this, but I don't think so. My last two paragraphs addresses what I think are RO's risks.

First there has to be bacteria in the municipal water. The city does a pretty good job there,

Second there has to be organic matter for the bacteria to grow. Again, cities are good with that.

But even if you have bacteria in your water, a good RO system's pores should be smaller than a virus (really smaller than a prion) or it won't be able to remove metallic ions.

But let's assume after two years these assumptions fail because the filters get old. Replace the filters and flush the system with bleach.

My fear with RO are bad filters. I once had a Zero pitcher and it tasted bad, acidic. A few weeks later there was a recall that the RO membrane was leaking ionomers.

Moral of the story- trust your senses. If municipal water tastes bad, it's bad. If bottled water tastes bad, it's bad. If RO water tastes bad, it's bad.

malfist•43m ago
From someone that keeps aquariums, municipal water that is stripped of it's chlorine by carbon has the ingredients to grow bacteria. They need three things, carbon, phosphate and nitrogen, all of which will be present to varying degrees. Particularly nitrates and phosphates. They're not harmful until concentrations are really high but certainly enough to grow bacteria.

Also consider what your holding tank and supply to the water, either through leaching, accumulation or simply time

StopDisinfo910•5h ago
I think the writer is sidestepping the main issue most of the people who want to filter their water are thinking about. Sure, your tap water is within the federal limits for contaminants. The issue is that these limits are significantly too high for PFAS out of convenience for the water supplying side.
cypherpunks01•5h ago
A surprising amount of Americans refuse to drink tap water entirely, in their own suburban homes with quality municipal water, or anywhere else they travel, holding the opinion that plastic bottled water is safer and better. Of course bottled water is regulated far less than tap water, and contains an ungodly amount of microplastics from manufacturing and storage.

Under-sink RO systems seem pretty great to me, anywhere you live. With a small holding tank, municipal water pressure is enough to drive small RO cartridges, requiring no electrical power to run, and giving more than sufficient flow rate for all drinking water. I think the biggest downside is a few hundred dollars in initial setup, and cartridges every year or two. This seems safer than relying on the changing opinions of experts as to what amount of harmful chemicals are safe to drink.

BugsJustFindMe•4h ago
> A surprising amount of Americans refuse to drink tap water entirely, in their own suburban homes with quality municipal water

It shouldn't be surprising that Americans might understand that their water might not actually be safe despite the municipal government saying it is. It took two whole years for administrators in Flint, Michigan to acknowledge their lead pipe crisis. Trust needs to be earned and maintained, and America is notoriously bad at maintaining critical public infrastructure.

n4r9•1h ago
> America is notoriously bad at maintaining critical public infrastructure.

How does that compare with food safety in commercial products? That's the question.

porphyra•4h ago
Even if safe, municipal water where I live (San Jose, California) contains a ton of chlorine and is super hard, making it unpleasant to drink. In contrast, bottled water consistently tastes fine.
adastra22•4h ago
San Jose water is absolute trash. There may not be (much) lead, but there are a host of other minerals and contaminants. It’s also a roll of the dice whether you’ll find Legionnaires' disease in your pipes.

I have a whole-house soft-water filter for general use, and for drinking/cooking get 5-gallon bottles filled with RO purified water from The Water Spring on Homestead in Santa Clara. The municipal source for RO water matters, and Santa Clara has the best utilities in the valley.

http://waterspring.com/

Stay safe out there.

Barrin92•4h ago
sorry if this is a stupid question because we don't have chlorinated water in Germany, but do people brew green tea or good coffee with tap water? Doesn't it taste god awful? One of the things which I remember from my holidays in Spain as a kid, which is one of the few countries which adds it here, is that the water tasted like pool water.
shigawire•4h ago
If you drink it all the time you are used to the taste. At least that's how it is for me
donnachangstein•4h ago
> but do people brew green tea or good coffee with tap water?

I use filtered tap water (under-sink type) which removes most of it.

A lot of the higher end coffee makers like Keurig have built-in filter cartridges in the water tank.

Most commercial coffee maker setups I've seen (hard-plumbed) in offices have a filter attached to the plumbing behind the appliance.

Water can be safe/potable and taste terrible, and vice versa.

justincormack•3h ago
Water is chlorinated in Germany [1]. There may be less as ozone may be used as primary disinfectant.

[1] https://www.lenntech.com/processes/disinfection/regulation-e...

lxgr•2h ago
At imperceptible levels.

Compared to that, in New York, I can definitely taste it and it took some getting used to. (Ironically, at this point my senses seem to have been rewired to associate the taste of chlorine with fresh, i.e. non-stale tap water.)

mousethatroared•2h ago
Its extremely unlikely that German water isn't chlorinated. Perhaps you are thinking about fluorinated?

Chlorine in water is actually fine and tasteless at the concentrations it reaches at the taps - it's basically extremely diluted stomach acid.

The problem is chloramines caused by chlorinated organics. These give water the swimming pool smell and are bad for you.

The solution is easy - reduce the organics in the water before chlorination, and oxygenate (aerate) the water before delivery. But systems can get overwhelmed by too much rain and runoff.

lxgr•2h ago
Chlorination of drinking water is indeed uncommon in Germany.

If it’s done, the level is often imperceptible, contrary to the US (I actually had to look this up – I’ve never tasted it in German drinking water in various cities myself).

mousethatroared•59m ago
How do they sterilize it?
an_aparallel•1h ago
My general experience in Australia when i talk about drinking RO water is that im looked at like a crazed madman who drinks "holy water"... So atleast hear i daresay its safe to say the average persons taste and smell must be piss poor
rincebrain•1h ago
You can get inured to just about anything with enough exposure, barring exceptional circumstances where you have difficulty learning to ignore things.

Visiting friends recently, they have well water which smells like sulfur from their tap. Visiting them for a few days, I do not get inured to it, but my friend cannot tell it's there.

tomatotomato37•35m ago
Yes, water quality matters a lot in coffee enthusiast land. They actually make little mineral packets that you add to a gallon of distilled water to get a "perfect" brewing water - I know since I actually use them for my espresso machine to fight scale buildup from my +10 grain tap water.

Note this excessiveness is really needed for espresso though; a regular Brita jug handles more tolerant methods of brewing perfectly well (and to be honest most people murder coffee enough that the water is the least of their concerns)

laex•32m ago
Do you have a brand name or amazon link for the mineral packets ?
tomatotomato37•28m ago
I use "Third Wave Water" but there are other brands out there
darth_avocado•4h ago
One side effect of RO is vitamin B12 deficiency. And there is some debate around whether that is true or not, but anecdotally, I had developed a severe B12 deficiency to the point that one day out of the blue, I couldn’t move one of my legs. I freaked out and went to the ER, and it turns out, 1 B12 shot later, I went back to normal within minutes. The doctor hypothesized that I had developed a severe B12 deficiency because of RO water and that I supplement my food with B12 supplements. The regular intake of meat/eggs wasn’t sufficient to compensate for the lack of B12 absorption.
cinntaile•4h ago
What's the mechanism here? Because it's not like there is B12 supplements in the water.
micromacrofoot•4h ago
reverse osmosis removes minerals like cobalt, which are used for b12 production

if you only drink ro water it can creep up on you, but takes some time

mometsi•4h ago
It's not used for b12 production in human metabolism. It is, after all, a vitamin. Is this about cobalt deficiency in dairy and meat animals?
s0rce•1h ago
How much Co is in your water compared to your food. EPA says just 2 ppb in tap water. This means if you drink about 40 fl.oz. per day you only get 2ug of Co from your water. Per the EPA you get about 2-20x more from your food. Pretty much in no cases is your water a source of nutrients.

refs:

https://www.epa.gov/sites/default/files/2016-09/documents/co...

https://www.cdc.gov/nutrition/php/data-research/fast-facts-w...

kadushka•4h ago
I drank only distilled water for 16 years. No supplements all that time, just regular food. No B12 deficiency or any other health issues.
unyttigfjelltol•4h ago
Similar risks regarding removal of sulfate from public water supply, or via filtration.[1] Who knew! Some of us were relying on actual nutrients from the water all along. Pristine water was, and is, a challenge for this cohort.

[1] https://biomedres.us/fulltexts/BJSTR.MS.ID.006372.php

mometsi•3h ago
In the linked article, rybett@aol.com uses the CORREL function in an openoffice spreadsheet to determine a weak correlation between autism diagnoses and sulfur content in tap water in a few regions of New Jersey.

His other publications include a self-published amazon book titled Autism, Enzymes and the Brimstone Demons. [1]

[1] https://www.amazon.com/Autism-Enzymes-Brimstone-Demons-Trill...

bbarnett•3h ago
Interesting.

I'm on a well, but with super hard water. So I have a water cooler, which I empty into a Brita pitcher, but just for drinking.

Just for the flavour.

I cook with my hard water though. Lots of stews and soups too, make bread, etc. So I suspect I get sufficiently mineralised as a result.

For context, I was boiling a large pot of water and got distracted by a call. Most of the water boiled away, well over a gallon. I was left with a solid white disk of calcium at the bottom. Also, when I broke it to get it out, it was super sharp, almost cut myself.

eesmith•2h ago
The only papers I could find in Google Scholar about this connection all come from India, and does not seem strongly connected. The study at https://journals.lww.com/jfmpc/fulltext/2025/04000/prevalenc... , for example, says:

> While some studies have hypothesized that the use of RO water could contribute to vitamin B12 deficiency, no significant differences were observed in this study.[20] Symptoms of deficiency were not significantly associated with serum vitamin deficiency status. Only VDD was significantly associated with fatigue as a symptom. This discrepancy raises questions about the current normative values for vitamin B12 and vitamin D3 in the Indian population and suggests the need for further research.

A whole lot of people drink RO water. If it were a simple correlation, I would expect to see cases and papers from all across the world.

I also know there's a long history of false claims along the lines "distilled water sucks the minerals from your body", also called "hungry water". I first heard in the 1980s as a supposed reason for not using distilled water in a radiator. Or even commentary of it in the Carnivorous Plant FAQ at https://www.sarracenia.com/faq/faq3385.html .

Because of that long history, and the lack of a good mechanism for how it should work, I need a much higher level of evidence for a direct, causal connection.

mousethatroared•2h ago
If water is giving you any nutrient in a significant manner, change your diet.
jandrewrogers•1h ago
Some essential micronutrients such as arsenic are primarily sourced from water. You don’t need much so most natural sources contain enough. There is actually a valid concern that obsessive over-purification of drinking water can lead to deficiencies of some trace minerals.
rsync•1h ago
Wow this has gone off the rails quickly.

To wit: Arsenic is not an essential micronutrient.

"Trace quantities of arsenic have been proposed to be an essential dietary element in rats, hamsters, goats, and chickens. Research has not been conducted to determine whether small amounts of arsenic may play a role in human metabolism." [1]

[1] https://en.wikipedia.org/wiki/Arsenic

jandrewrogers•53m ago
There is substantial evidence that arsenic is a required micronutrient in all mammalian biology. This is not even controversial, you can reliably induce deficiency syndromes in a broad spectrum of animal models, and the operative pathways exist in humans. The effect was first observed in animal husbandry in parts of the world with very low background arsenic levels.

It has the same toxicity and micronutrient profile as selenium, another extremely toxic but nonetheless essential micronutrient. Unfortunately, activists with an unrelated agenda have been spreading unscientific misinformation about arsenic to advance that agenda.

Same story as fluoride outrage actually. Being anti-science is fashionable and most people are ignorant about chemistry.

It is one thing that makes me glad I am no longer a practicing chemist.

rsync•10m ago
If what you are saying is true – and I am not being sarcastic - I encourage you to edit and update the Wikipedia page that I referenced.

The authority that I have appealed to (Wikipedia) is a reasonable one and no bias is implied in the absence of these, supposed, Corrections you have to make.

I’m open-minded …

mousethatroared•1h ago
Eat a serving of rice, preferably American, without rinsing it.

Enjoy your 10000% recommended daily intake of Arsenic.

jandrewrogers•39m ago
Background levels are much higher than current standards with no observable effects in many parts of the world. This is well-studied. There is a threshold but it is higher than people assume.

Plant-based arsenic often has poor bioavailability. Quite a few plants people eat are natural accumulators but it just passes through. Pesticides and geology are the primary bioavailable sources.

an_aparallel•1h ago
My RO system has a remineralisation cartridge. You def dont want to drink ph neutral water, it feels hard, and doesnt taste sweet.
hollerith•4h ago
In your second paragraph you seem to be describing carbon-block filtration. Particularly, the maintenance of an RO system consists of a lot more than just replacing cartridges every year or two.
margalabargala•4h ago
Could you elaborate? I have an undersink RO filter. Maintenance consists of changing filters every year or two.
tguvot•2h ago
you need sterilize entire system periodically. and completely empty/refill tank once in a while
margalabargala•2h ago
I totally believe that the system you have requires this, but plenty of others do not.

Here's the maintenance manual for the one I have. The sterilization and emptying/refilling are done as part of the filter replacement, and not otherwise:

https://www.whirlpoolwatersolutions.com/wp-content/manuals/W...

tguvot•2h ago
" Maintenance consists of changing filters every year or two." it's not same as "disconnecting lines and pouring bleach inside when i change filter" or using "Manufacturer recommends using the Model 7301203 Sanitizing Kit"
an_aparallel•1h ago
You need to change filters as recommended, change o-rings, and bleach the fittings. Algae will develop on those. Thats pretty much it.

I wouldnt run bleach through the filters. The filter medium saturates, and any further use will just recontaminate water

zahlman•3h ago
> ... bottled water ... contains an ungodly amount of microplastics from manufacturing and storage.

Is it worse than the other groceries we can't readily get without them being wrapped in plastic? Or storing leftovers in plastic bags at home?

s0rce•1h ago
My guess is yes, because they can more easily get into the liquid. Unless you are talking about other liquids like juices or canned foods, those I would expect are similar or vary depending on the type of plastic.
jandrewrogers•1h ago
The water in some parts of the US has natural chemistry that makes it unpleasant to drink even though it is safe. California urban areas are notorious for this, as an example. In principle you could remediate the water to make it taste good and remove any discoloration (also a thing in a few regions) with enough industrial processing but that would greatly increase the cost of already expensive tap water.

People who grew up in one of these areas are habituated into never drinking the tap water even if they move to a city with excellent tasting and very high quality tap water. I’ve lived in extreme examples of both.

You also see the opposite case, where someone who grew up with amazing tap water naively grabs a glass from the tap in north San Diego and has a “wtf is this” moment.

PlattypusRex•1h ago
San Diego's tap water tastes truly awful. The first time I ever traveled to another city (Denver), I was forced to drink the tap water and could not believe how good it tasted.
jandrewrogers•1h ago
San Diego has the worst tap water for drinking I have ever experienced in the US. When I lived there, pretty much everyone had a reverse osmosis system installed to make it drinkable.

Fortunately, I live in the Pacific Northwest currently, which generally has some of the best tasting water you’ll find anywhere. No one would dream of not drinking the tap water.

mousethatroared•1h ago
A surprising amount of Americans live in cities that cheaped out on the water infrastructure and found out their water had lead.

Like me.

Luckily, I am very unreasonably distrusting of government and never drank the stuff.

atoav•5h ago
I also don't filter my water, but I live in central Europe and our tap watrr adheres to stricter standards than bottled water, so there's that.
m3kw9•4h ago
Yep use it if it makes you feel better. I know water treatment people in my area have talked about the no need to use filters.
doug-moen•4h ago
The quality of your water varies with the district you live in. My municipal water provider puts chloramine in the water to kill bacteria. Occasionally we get high levels of chloramine, which is disgusting (smell and taste), but the water filter removes it. Occasionally they flush the pipes, which turns the water red, which is mentally disturbing, but the water filter removes the rust.

So while it's important to me that my municipal water is technically safe to drink, I still have a better experience with my drinking water when I use a filter. While it's amusing that this technical expert considers rust-red water to be "delicious", do they have family members, or friends that visit and consume beverages, and do these other people get to have an opinion?

9x39•2h ago
To be fair, he does say he isn't anti-filter, and I think his article was to calm the horses and hysteria out there. I filter water too, but it is things like testing maps (https://www.ewg.org/interactive-maps/pfas_contamination/map/) that really help eradicate the brainworms that I'm slowly poisoning myself from the tap.

I think the whole article was a pretty solid attempt at helping people like myself who tend to overreact when it comes to exposure figure out that the fear and the danger are often not the same.

BTW, unless you were just being sarcastic, the rusty water was him talking about the filtered water from a LifeStraw - something that's miraculous as far as I'm concerned, seeing as I've drank mucky water out hiking through them just fine. Well, probably, anyway.

calmbonsai•4h ago
Wirecutter was bad before the NYT acquisition and now it's lot any/all remaining credibility.

Much like CNBC, it's completely "turned the corner" for me and I take their editorial as a negative signal.

In other words, definitely filter your water.

bobxmax•2h ago
> Wirecutter was bad before the NYT acquisition

How so?

timerol•4h ago
> I hated my pitcher filter long before I knew I didn’t need it. It would clog up any time a bit of rusty water came through the pipes, which, in a 70-year-old building with cast-iron service lines, was often.

I'm a little confused that this is used as an argument against filtering water. I get that iron is not a particularly worrisome contaminant, but I still don't want the occasional "bit of rusty water" showing up in my glass

bradlys•4h ago
So, his suggestion isn't to buy a water filter system and filters that could last you 10+ years but instead to pay $300 for a test. Retarded. The NYTimes is such a joke and so is this guy. If you're living in newer construction in a place like NYC then you're likely going to be fine. I am in this group currently but I will be moving back to the bay soon and I will have to use my RO system.

If you live in the bay area, you know you have to filter your water because it tastes like metal. We hadn't even had an electric kettle for more than six months in our startup with less than 5 employees using it, the entire bottom of the kettle was covered in 1/4" thick plates of various minerals. Obviously, water differs per city but this was a common occurrence throughout the bay area. The water, of course, always tasted poorly. I'm not even getting into how the housing stock in the bay area is decrepit and full of homes and apartments that are nowhere near up to modern construction standards. You have copper pipes? That's cool but you probably still have lead solder in those pipes. Who knows what kind of supply pipes are coming off the street. Yeah, your local supply probably replaced the ones that run in the street but the ones on your property? Unlikely. Your fittings? Still could have up to 8% lead until 2014. The amount of homes I'd see that still have knob and tube wiring was astounding. You can bet your ass that place still has an abundance of lead all over it.

The poor tasting water in the bay area is reason enough to filter it - even if it wasn't for all these other issues like most homes not being up to modern standards. A lot of these water tests are done at the county's office. It does not reflect what your home will add to your water supply. So, yeah, getting at home test could be nice... for $300... or you could just install a nice RO system that will last many years and give you better water anyway.

dbcooper•4h ago
>Why you should trust me

Absolutely zero mention of qualifications. If you do not have a chemistry/chemical engineering degree, or something closely related then why would anyone want to bother with your verbose writing?

sitzkrieg•3h ago
ah yes, degrees. i only absorb information from qualified individuals with degrees.
brookst•3h ago
What qualifications do you look for, or do you just assume everyone who says they’re an expert is actually an expert?
bobxmax•2h ago
Wirecutters is a long-running very trusted publication. It's not a random rag.
mihaaly•2h ago
Knowing something well is not dependent on formal education. Helps quite some, but not being a must. And more importantly: not a guarantee!
recursivedoubts•4h ago
I'm a dude who doesn't care to run a chemical analysis of my municipal water every couple days. I filter my water.
mihaaly•2h ago
Have you tested your filtered water - in various conditions - or you just trust it based on the words of others?
recursivedoubts•2h ago
I just trust the carbon filters. Sorry.
mihaaly•1h ago
Who told you to? : )
rufus_foreman•1h ago
You just trust corporations.

I mean I trust corporations more than I trust the government, but 0.002 is more than 0.001.

You seem like a very trusting person.

s0rce•1h ago
If you don't test it how do you know what filters are needed to remove the contaminants. You may be filtering out things that aren't there and not filtering the actually hazardous things in your water. Although you probably guess things like PFAS and microplastics which appear to be ubiquitous now.
tonymet•3h ago
if you are someone who regularly cleans and replaces your water filter, it's probably not hurting.

For most people their water filters are probably contributing more mold and contaminants than removing.

internet_points•3h ago
How much PFAS does the average water filter add to your water?

(How much PFAS do you get from plastic-bottled water / soft drinks instead of the stuff coming out of metal pipes?)

torqueehmada•2h ago
Go find out and tell us. That would be really helpful information.
s0rce•1h ago
You can probably review the wetted materials but fluoropolymers are more expensive and not required in consumer water filters so I would assume not much PFAS. If its some activated carbon and IEX resins then its likely not making things worse.
knappe•2h ago
I go back and forth on the issue. I read our local municipal water reports but then things like this happen https://www.vaildaily.com/news/climax-mine-can-now-release-h...

Denver water couldn't force the mine to continue cleanup of the molybdenum (because they're bankrupt) and instead raised the tolerable levels of molybdenum in Denver water. The same thing happened in 2017, 2010 and I'm certain before that. And then we have things like this https://www.cpr.org/2025/06/04/free-private-well-testing-ote...

Colorado has some serious issues with mine runoff and water contamination.

https://www.pagosasun.com/stories/the-day-the-river-turned-o...

Arch-TK•2h ago
That's nice. In the UK, tap water tastes like chlorine. If you are unfortunate enough to have chloraminated water, just letting it sit is insufficient. You need a filter which can remove the chloramine. After this, the water is actually too hard to make good coffee with, so I either zerowater it or distill it and then mix it with the filtered water using a TDS meter to hit a rough reference point (EC meters are not accurate gauges of TDS, but that's fine, you just want a consistent TDS not a precise TDS).

So sure, if you live in a civilised country and your water doesn't taste like shit and doesn't make your coffee taste awful and you trust your government to not give you poison or have tested your water to ensure it won't hurt you, go right ahead, be my guest.

But I will continue filtering my water because I hate the taste of chlorine and want to make the best out of the expensive coffee I buy.

storus•2h ago
After covid I noticed that drinking tap water was making me noticeably worse but buying packaged mineral water didn't (this was done over a few months). I later bought reverse osmosis and never hit that problem since. However, this year I learned that I live in a high-PFAS area (up to 300ng/L) so I am wondering if I was hitting PFAS overload somehow. Most of my flowers died quickly after watering them with the same tap water as well (when I still tried to have some house flowers).
bilsbie•2h ago
Any concern about pharmaceuticals making it into tap water? Microplastics?
constantcrying•1h ago
Where I live there are area local water reports, so you can enter your street and see where your water is coming from and a report, with quite a lot of measurements and including legal limitations for these measurements.

Water filtration should be an informed decision, based on what water you are actually getting.

foresto•1h ago
> It is also certified for Particulate Class 1, which is a surrogate for microplastics.

Based on a web search, it looks like Particulate Class 1 means particles in the 0.5 to 1 micron range. Several carbon block filters are rated at 0.5 µm, so I guess they're meant to handle those microplastics, but it leaves me wondering:

Do any smaller microplastics exist? Are they likely to be present in municipal water supplies?

All the filter cartridges that I've seen, and almost all the housings and tubes that hold them and the water, are made at least partly of plastic. Given that water typically sits in these filtration systems for hours or days at a time when the tap is closed, could it be that microplastics are leaching into the water from them?

deepsun•1h ago
Well, the current US administration is all against the environmental protection, so I expect the article advice might change in the nearest hears.
kdlskall•1h ago
The whole topic seems to be infused with a lot of loss-of-control issues…

In the end, there’s just so many more vague risks affected by the society you live in.

Driving a bit slower will probably offset a great deal of those.

dbg31415•1h ago
Filtered water tastes better.
t0bia_s•1h ago
Our tap water has strong chlorine smell. Since we add a filter, chlorine smell is gone and water taste better. When I drink unfiltered water from my parents house, I immediately recognise it.