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Comment by Areading314 | Hacker News Reader

Great point. Especially given how wasteful we are with drinking water there is far more room for efficiency on the demand side than the supply side.

This source says we use 80-100 gallons (304-380L) per day (in the US) https://water.usgs.gov/edu/qa-home-percapita.html

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At $2000 per acre-foot, 100 gallons costs 61 cents.

That's right, $2000 per acre-foot is $0.0061 per gallon.

So even at that cost all you have to worry about is the consequences of using the energy, the cost is no problem.

Wonder if we'll ever run dual source systems...like salt water is just fine for pooing in.

It’s a thing for Hong Kong. Something like 80% of toilets are flushed with sea water.

Chlorination is easy: just electrolyse the water on its way in.

Not sure what impact this has on sewage treatment.

Very interesting concept that I never considered. Shower with salt water and then rinse with regular water. Pay one price for salt, one price for regular water.

The salt water would probably be too corrosive to pipe significant distances, which would make that difficult to get enough scale to make it feasible.

Most of the dual-use water systems I’ve read about were fresh water vs gray water.

Much piping these days (>75% for major distribution pipes, and increasingly common in residential use) is PVC, which doesn't corrode.

Salt and minerals get into fittings, destroy valves, and coat everything when the water evaporates. Probably not a great solution.

You would have to purge your system and shower head with vinegar every day just to keep things clean.

You are assuming that only metal pipes exist. Nowadays most pipes are made by either concrete for the big ones (canal like) or plastic connected with glue that is rated for hot or cold water.

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