Something like a 1000 gallons of fresh water a day....  

If that low efficiency machine is in an apartment where they do alot of laundry and you are paying for water it makes a difference. 20 gallons more a load at least.

Any pool plastering company should be happy to send out for an estimate. 17,000 gallon pool with attached hot tub gave me quotes from $5500-$8500. 

With young tenants, hardly home, their regular garbage fits into a bag the size of a lunch, and when thrown into a 30 gallon pail, get blown over by a slight breeze rolling around the sidewalk and street.

Average 13 inches of rain per yearElevation change 12,600 down to 70 feet above sea level.56 people per square mile.Arizona 146 gallons per day average per person.  

In 15 years I have seen MANY investors getting caught, unable to sell their properties at break-even point when they needed.Not sure if you watch the News but half of the Midwest has been going thru some extreme weather lately, including estimated 7 trillion gallons of rain and tennis-ball-sized hail.

@Wai Wah ChanI work for a local water department as a meter reader, I would say @Dan Heuschele is pretty accurate with $100-$150  a unit (this of course depends on water rates and if you're billed in gallons or cubic feet).

Cost are not much more than oil , I have 1 house all electric baseboard , tenant complained about bill of $ 400.00 , I walked to the neighbor next door ( a friend of mine same type house) got his electric bill , it was $ 225.00 AND he went thru 110 gallons of oil at $ 440.00 , The tenant didnt complain again .

You can either put it under your name but charge it on top of the rent to each tenant,only keep one water meter connected (instead of multiple ones on same property) and pay it your self and charge higher rent in lieu of that and last, i saw once someone that have some kind of water meter clock connected on the line and can see how many gallons they spent per month, but then you would have to calculate each month the price per gallons consumed,etc.

I request for the to check again and they said they would comply. 2nd plumber comes. this guys says oh yeah you have a popped water expansion tanks on both sides of your units, the PRV valves are old and need to be fixed, and also her toilet seal is weak and could also let gallons seep through randomly.