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Comment by JohnJamesRambo | Hacker News Reader

A reminder that you can remove these and many other contaminants from your water with a simple undersink RO filter. They are quite inexpensive and start at about $160 on Amazon for a lifetime of clean drinking and cooking water.

https://www.canr.msu.edu/news/list-of-household-filters-appr...

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Shifting the costs to the consumer -- standard externality game.

Kinda like the companies that produce really gross chemicals and make the owner millions, only to become superfund sites that get cleaned up with taxpayer money many years later? :D

Out of curiosity, I looked up maintenance costs on RO filters. It looks like the filters that need replacing annually are $20-$30 for the set, and the membrane that needs to be replaced every 2-5 years is $30-$50.

I’ve found those guidelines to be pretty conservative. I think I’ve maybe changed the membrane once. A simple TDS (total dissolved solids) meter can be had on Amazon for <$20 that tells you if the water quality is changing over time and it is time for a change.

PFAS can be filtered by simple activated carbon filters. You don't need RO.

They can be absorbed through the skin so if you really want to avoid them you need a whole house filter.

I've heard this also removes many essential minerals that we get from water?

Yes, googling "reverse osmosis demineralized water" provides many options to add minerals back in.

The WHO stated that demineralized water is unsuitable for long term drinking due to the lack of minerals.

Not sure how significant this is or how many minerals you can get from diet instead of water.

Here's the WHO report for folks who are interested: https://www.who.int/water_sanitation_health/dwq/nutrientscha...

Drinking water typically does not provide significant quantities of any essential minerals. For example, the USGS threshold for "hard" water (heavily mineral-laden) is 120 ppm of combined calcium and magnesium carbonates. At that level, drinking the recommended two liters a day would only give you a few percentage points of your required daily intake of elemental calcium and magnesium.

How many gallons of water do you have to throw away to get 1 gallon of pure water with this system?

Looks like 4 to 1. Not great, but probably not a huge hit if you hook it up only for drinking water. I wonder how hard it would be to pump that waste water to your toilet tanks instead.

Some people just let it gravity drain to another container (inside or out) and then use it for outdoor watering.

The flow rate & pressure is typically very low for the drain water with these systems, so you'd need another setup to handle pumping it to your toilet, etc.

Sending it outside is probably the easiest way to immediately use it.

Unfortunately some areas only have need for outdoor watering a few months of the year, so other uses might need to be found.

you can also pick an ro system with a permeate pump (https://www.purewaterproducts.com/articles/how-permeate-pump...)

proper inlet pressure also improves efficiency.

Some companies have 1:1, gallon of clean to gallon of waste.

Here's one that's quite popular: https://www.theperfectwater.com/Home-Master-hydroperfection-...

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