Marginal water prices mean the price for amount of water needed for a family to bathe and cook and clean costs much less than the amount of water for landscaping around an opulent home.
If people are still too poor, then giving them cash (by taking from richer people) is the solution, not pricing water so low that it gets wasted
Lack of sufficient water and excessive income/wealth gap are two separate problems with separate solutions.
I'm not totally sold on on the idea, but it is very possible to create a tiered pricing system that makes domestic water waste unsustainably expensive. The price required to deter consumption may be absurdly high, but demand elasticity will always exist at high enough prices.
Prices need to be increased (or, in some cases need to exist) for agricultural use.
First, the point was that municipal water usage wouldn’t need and change and could actually decrease in rates if agriculture and industrial paid the same market rate.
Second, if we are talking about lawn watering, that’s absolutely a middle class thing in the vast majority of California.