In my province, many municipalities get their drinking water from both surface reservoirs (lakes) and subsurface aquifers (deep wells).
In spring and autumn, surface reservoirs are full of relatively clean water. In summer and winter, the reservoirs are half-full of dirty water, so municipalities pump water up from aquifers.
Municipal water wells have depths greater than the head of water on some hydroelectric dams.
Centripetal water pumps can be made to run backwards, with only minor modifications to turn it into a centripetal turbine.
Pumps are low-maintenance, with long service lives. The City of Toronto has century-old pumps still in active use.
My province has fewer restrictions on diversion of surface water than Alberta, Colorado, or California.
When surface water reservoirs are full, municipalities in my province could pipe excess treated water down wells into aquifers. The pumps would be turned into turbines, and the electric motors would run backwards and generate electricity. The municipality could then sell the electricity to the grid for a small profit.
Wells are expensive, turbines are expensive, but the municipality already paid for them. It wouldn't make sense to dig a well just for power generation purposes. But if you've already got the well, and you've already got the hardware, it's an opportunity to create revenue.