People want to be on the water not near it.

Then check to see if the water meter keeps spinning.

The issue with watering your foundation is that you have to do it always, every year without a break in order to achieve the desired effect.

If the water bill is $100 a month, increase the price by 20% (or whatever you decide is fair) to compensate you for the time required to split and bill and to cover additional use when tenants squander the utility.

I own a duplex in Clermont, FL just outside of Orlando and initially wanted to split water meters between the two units, but the cost and amount of work were higher than expected.

The easiest solution is typically keeping water away from the wall. 

Tenants stopped paying electric and water.

I have never pulled a permit for a water heater swap, know no one that has ever pulled a permit for a water heater swap, ever seen or heard about one getting red tagged for no permit, and have never had a plumber recommend getting a permit.

Running water through it? 

Then wherever the water is getting discharged off of the roof, that what water is getting at least 4-5 foot away from the structure before it is left to drain with gravity away from the property.