That’s pretty smart of them. If I ever built a new house I’d consider adding a gray water tank where laundry and maybe shower water could be diverted. The tank would be connected to a pressure pump and could be used for washing cars and watering the lawn.
I’ve got no problem with this. As an occasional backpacker, I’ve filtered plenty of water with no ill effects. If I can be confident with a $25 Sawyer Mini filter, I’m sure a municipal wastewater treatment plant will do far better.
Plus, that pesky 4th grade science class about the water cycle comes in to play. Water is a zero sum game. It gets treated, ingested, expelled, returned, treated, ingested...
>> a gray water tank where laundry and maybe shower water could be diverted <<
I believe that approach is illegal in certain places, because some municipal systems really and truly need your “used” water to keep everything flowing properly thru their sewers.
(A related issue in the California Bay Area has been that some of the sewers have backed up with disastrous results, due to there not being enough water to flush the lines. The main cause of the problem here seems to be that there are too many low-flush toilets. Hooray for environmenalism!)