If you own a multifamily investment property which you are renting out to 2 or more tenants, you’ll probably be disappointed to find out that there’s only one water meter (provided by the city) to the entire building located underground under the sidewalk. Following are some scenarios on how water pipes reach each unit and how to possibly measure each unit’s water usage.
Separate cold water pipes
Even though there’s only one water meter under the sidewalk, it’s possible that the downstream water pipe after the meter branches into multiple pipes, one for each unit, thereby creating multiple cold water networks If this is the case, then you’re in luck and you can install a water meter, e.g. Badger Model 25 or Neptune T-10 at each branching water pipe.
Shared cold water pipes, separate hot water pipes
If the cold water pipes from the city’s water meter go to all units in a shared manner, then it would be very difficult to measure water usage by unit. However, if each unit has its own hot water pipes that are not shared with other units, which would be the case if each unit has its own hot water heater, then you can measure hot water usage by installing a water meter at the cold water inlet to or the hot water outlet from the water heater.
Billing each unit for water
Usually there will be one water bill for a multifamily property. Since there are multiple tenants, you’d need to fairly split the bill among them based on each unit’s water usage.
Based on headcount
If both hot and cold water are shared among all units, then one common method is to bill each unit proportionally based on headcount (number of occupants). If one unit has twice as many people living in it as another, then that unit would pay twice as much for water. Of course, headcount can change over time so this would need to be updated whenever there is a change.
Based on hot water usage
If cold water is shared but hot water is separate, then you can split the water bill proportionally based on hot water usage. This would be more accurate that going based on headcount.
Following are some popular water meters for residential use.
Badger Model 25
This meter has plastic threads and costs about $100.
Buy online – RC Worst
Buy online – QC Supply
This meter has metal threads and costs about $100.
Smart Water Meters
The water meters above are manual read meters. To measure water usage remotely and see usage over time, you can buy a smart water meter. One of the best ones is Flume 2.
Flume 2 Smart Home Water Monitor
This smart water meter does not require plumbing as it is just attached or strapped around a compatible water meter. It costs $200.
The Flume water monitor just straps onto an inline water meter. It reads the magnetic field generated by your water meter, which the company says can detect any water usage all the way down to one one-hundredth of a gallon — i.e. a slowly dripping faucet.