The prices should not go up a lot, because if they did, farming would become unprofitable.

E.g., tomato farming produces around $4000 worth of produce per acre and year[0], and requires 2.5 feet applied water. ($4000/acre)/(2.5 feet) = 0.5 cents/gallon. If the water got that expensive they'd need to stop growing tomatoes, since just the water would already cost more than the produce would be worth.

By contrast, residential water is 0.7 cents per gallon[1], so the prices involved are really tiny compared to what human users are already paying.

[0] https://www.nass.usda.gov/Quick_Stats/Ag_Overview/stateOverv...

[1] https://www.calwater.com/docs/rates/rates_tariffs/ela/202201...