If you ever drive through the part of the Imperial Valley which is just artichokes, you'll viscerally get the point I'm about to make: you shouldn't be deciding whether square miles of artichokes are a more productive use of water than someone's lawn. No one is starving without artichokes, lawns make people happy.
We solve this kind of problem with markets, or in California's case, we flagrantly ignore the solution and start fucking with people's supply.
How about making the price graduated. Each household has a low price up to a certain point (a reasonable amount for indoor use of the household) and after that it's market price.
Some households have more residents than others. I don't particularly want intrusive government monitoring of who lives where just for the sake of water allocations. No thanks.
I don’t know that any such tiered pricing needs to be down to the liter.
I think it would be perfectly reasonable to assume that agricultural water from individual farms dwarfs that of individual residences, so you just need to find the cutoff at which residential allowance stops applying.
Get an estimate of the maximum people/bedroom in the area, then judge each house based on that. I think the city already knows how many bedrooms each house has.
Don't be ridiculous. No one is seriously proposing completely cutting people off from water. Flow restrictors still allow customers enough water for personal consumption and hygiene.
We solve this kind of problem with markets, or in California's case, we flagrantly ignore the solution and start fucking with people's supply.