Ask HN: How to ensure your water is safe to drink?

you've hit upon a thorny problem. water testing services only test for obvious things like heavy metals, leaving organic contamination (i.e. drugs, industrial chemicals, etc) pretty much untouched. There are rather disturbing maps of American obesity levels that correlate well with river drainage basins. Reverse osmosis filtering is the answer, but you'll need to supplement to replace lost minerals like calcium, etc.

Be careful about going overboard with a whole house filter. Your municipal water has a residual disinfectant (chlorine or chloramine), and, if your utility is at all competent, they’ve adjusted the pH and other chemical parameters to prevent the water from being corrosive to copper, brass, and lead.

If you filter the water where it enters your house, you may change the chemistry, and you are quite likely to dechlorinate and possibly dechloraminate your water. So now water that stagnates in your pipes can start growing things, hot water in your water heater might be more likely to grow legionella, and your pipes and fittings might be more likely to leach metals.

You could consider an under-sink filter. They’re quite inexpensive and fairly easy to install. And you don’t use up their capacity for things like flushing the toilet.

Filters introduce additional risk because they themselves can become dirty (or even contaminated). Looking inside a well-used water filter can be a horrifying experience.

Personally, I filter all water because I’m an obsessive but I’ve come to realise that I’m probably increasing the likelihood of exposure to something not-good — because now I have complete responsibility for maintaining and cleaning my filtering, no big government machine keeping my water clean, just me and my human negligence.

There are never ending risks to everything we do, be mindful you don’t get caught up in trying to make everything perfectly safe — especially if you have children, the paranoia and worry is more transmissible than whatever is in your water.

I've moved neighbourhoods, counties, cities, states, countries and continents. I've learned that a public utility is to never be trusted nor a private utility. I start with using a tap filter, something like the Brita series. Then I add a shower filter. Those two are the first initial setups I have in regards to water at home. From there I'll take note under a specified time frame if there are any pros and cons. Context would change for you.

If you live in an older house or neighborhood, you should absolutely test your water for lead. Even if you house is new, there could be a gooseneck to the city main that is lead. Some cities even offer heavy metal testing for free.

Other than for taste or hardness, I never felt particularly like filtering water. I don't think I can outsmart the dozen PHDs that run our municipal water system and don't want the hassle or waste of dealing with filters.

Also, obsessively filtering water can come with it's own health concerns. You can filter out the treatments added to water that prevent toxic algae from growing. And natural impurities in our water are actually a very underrated and important source of minerals.

Before you decide to do any filter/treatment it is a good idea to get a lab test.

Testing water can get a little complicated and expensive. Ideally you’d test at the water source (where it enters your home) and at the point of use (where you pour it into your cup to drink it). This way you know the quality of the source water and the quality of the water after it flows through your pipes.

Testing this way can get expensive though. Also, ideally you’d test about once a year to see if there are changes.

Once you get the test results you’ll know what specifically you need to do to treat the water. You may not need anything.

I would suggest using Tapscore for the testing. I’ve used them in the past. https://mytapscore.com/

One final bit of advice, if you do want to get something like a reverse osmosis filter, go to a company that makes RO filters and send them your test results. I learned the hard way that there was too much radon in my water to work with the very expensive RO filter that I bought.

The EWG has a tap water database [0] that I used to get a rough estimate of my tap water quality. Since it was above their recommended levels in several chlorine-containing chemicals and a few radioactive elements, I decided to get an under-sink Aquasana water filter (I’d have gotten while home if I didn’t rent). The one I got is certified for pretty much every known harmful substance, at the highest certified level, as far as I am aware. I haven’t gone full mistrust and tested my water after the fact to ensure it works as advertised, but the water tastes noticeably different and I have personally noticed changes in my energy levels since adding the filter. There are too many unhealthy compounds that are not monitored for, or are under-monitored for, to justify skipping out on water filtration IMO.

[0]: https://www.ewg.org/tapwater/

Berkey filter with charcoal elements. Supposedly it can remove bacteria (but not viruses). All I know for sure is that it makes the water taste a lot better.

I've had the same filter elements in mine for years. Recently I needed a glass of water for my night stand and the filter was empty. It's slow to fill so I just filled the glass from the tap. I thought the chlorine would evaporate overnight. Well maybe it did, but one way or another the water still tasted gross the next morning. So the filters are still doing something. And that's after 5 years.

If you happen to live in the Upstate then you have little to worry about. It's some of the best in the nation. Not sure about the Midlands and coast.

What would you test for besides lead? Most contaminants have a very low threshold which is going to be expensive to detect.

It's probably a good idea to use an RO filter regardless. It's a very straightforward way to reduce toxins directly entering your body. Virtually everything is now contaminated with environmental toxins, and we're effectively being bombarded. You can't avoid them but you can take steps to minimize your exposure/reduce your risk

This is a good database of water quality: https://www.ewg.org/tapwater/

Maybe someone with more knowledge in this area can provide enlightment, but I always heard that eating plenty of fibre, such as wholemeal bread or greens like cabbages, broccoli, kale etc, could absorb toxins and carry them out of your body. In which case this could compensate to some extent if your tap water is contaminated. Of course, high fibre may also carry away the good stuff like vitamins too. Just wondered if increasing fibre intake is a realistic way of protecting yourself. Seems to me some of the tap water contamination a filter may not do much for. And... do you trust bottle water really? where has that come from? Here in the UK we don't even test for PFAS AFAIK, which is scary.

I smell it, look at it and taste it. If it passes these tests I drink it and wait to see it I react in any way. If I don't I declare it safe and tell the rest of the family. If it smells funny I go and have a look at the well to see if there's anything strange there, I one caught a whole family of frogs in it.

Yes, we have our own well, about 5.5 m deep and 1.20 wide, lined with concrete rings. It is dug through a non-permeable layer at the foot of a hill which makes the water level in it higher than ground level, making it nearly impossible for surface water to make its way into our supply. When the thaw comes the water gets a bit cloudy from silt (which is what lies between us and bedrock, a layer of a few metres here and there as memory of the last glaciation). I pumped it out once to do some repairs, put a layer of gravel on the bottom and put in a new back valve, for the rest it has worked fail-free in the more than 20 years that we live here. I did have the water analysed after the repairs, it was fine. So are we. So will you be, without any silly filtration systems unless your municipality really messes up their water supply.

Depends on the area.

- Whole house filter consisting of specific commodity 20" large ("big blue") filters

- (NaCl) ion exchange water softener sized for the hardness -> hot and cold water to most indoor piping except kitchen cold water (for watering plants) and outside

- 6 stage + UV 100 GPD RO filtration system using commodity parts. Add a permeate pump option to transfer pressure and reduce waste. There is no real cost difference in production flow rate between 5 GPD and 100 GPD except losses, minor membrane differences, and the restrictor valve. 200 GPD is tankless, so that's a minus.

A US So Cal manufacturer, AMI / wateranywhere.com can ship large orders by freight for 1/3 the price a plumber will charge for a crappy wholesale system. They make RO membranes and industrial-scale desalination systems, so b2b and b2c are side markets for them.

Clean out everything and run antimicrobials at least every 4 months.

It's work, but having nice showers and clean water down to <1 ppm is awesome.

PS: For apartment dwellers in large cities, find a reputable "water store" that has both a commercial AND retail business from the same equipment. Buy your own non-PFOS containers from the REI or some such. Sunray Waters in ATX is one example.

You can only test at a point in time. So you want to test periodically. Since it sounds like you are on municipal water, 12 months should be ok, 6 months if you're feeling paranoid. I'm on well water and test frequently.

Home testing kits are cheap. Sending it out to the lab is pricey but you get more detail and consistent results. For lead, home testing is fine. You should do at least one mail lab test to start with. Unless your house is ancient, almost certainly you won't find lead. Your water company should be using "clean" sources to ensure no lithium, magnesium and such.

I have an RO, only because I have a water softener, otherwise I wouldn't bother, and didn't anywhere else I lived. I trust the engineers and scientists at the water company more than some shady filter dropshippers.

If you -really- care, you could always distill your own water. It's pretty cheap and easy to do so.

Just get an under-sink reverse osmosis system in your kitchen, and have it piped to your ice maker if you have one. Better to have excellent filtration of the water you actually use rather than mediocre or expensive filtration of house water, much of which is going to go to bathing/cleaning etc.

Where I live I get my water from a well, actually - and the regional public health office provides sample bottles for testing. They ship them off to a larger city's health unit for testing, and it takes weeks, but services exist, and they may in your area too.

The only reason I would consider a whole house filter is if I wanted to run the whole house off well water. That's not really just a simple filter though, at that point you're processing the input such that it won't ruin appliances, etc.

At a minimum your local municipality should be running tests periodically and sending you the results in a newsletter of some sort.

If they are not running sufficiently thorough tests for your liking, you can get your own testing done and go from there.

i would not rely on any government testing, especially as they would not test the last part of piping anyways. it is not cheap (i pay 60 to 200 euros depending on lab and amount of tests) but i found two of my flats had non drinkable water with lead and bacteria levels multiples of the max allowance. i could never understand why there is no rule that every building has to have an official water test at least once like the energy ratings.

Buying a simple Brita filter is probably a good idea, right?

With regard to lead, I recently found out that most faucets manufactured before 2014 have lead in them. I found this out while replacing parts for a faucet in a house built before 2013.

https://www.mwra.com/04water/html/Lead_Faucets.htm

tl;dr: if you think your faucets are older than 2014, run the cold water for a bit before filling a glass for drinking.

I'm on a rain water tank so would also appreciate some advice there for DIY style where you don't have access to municipal water..