Many owners ask us how to submeter the water usage on a ADU they own or are building. Submetering is not very complicated but there are a few steps we recommend taking to make sure everything is set up correctly.
The best time to set up the ADU for submetering is prior to plumbing, working with your plumber to ensure that there is a convenient location to locate the submeter so that it accurately tracks all the water (both hot and cold water) flowing to the separate unit. All of the water piping that ultimately feeds the ADU needs to flow through the submeter to get accurate readings. If your plumbing system isn't set up so that you can install a submeter before the hot water heater, then you will need to install 2 submeters, one for the hot water and one for cold water. It just means you will have to purchase and install two meters and take two sets of readings everytime you want to generate a bill.
Once the plumbing is installed, the submeter can be installed. The submeter should be installed in a location that is easily accessible for reading and maintenance. It should also be installed in a location that is protected from freezing temperatures. We often see the submeters installed just before the cold water splits to the water heater, which is typically in a water heater closet or garage.
Once the submeter is installed, readings from the meter will have to be taken at the same time as the main water bill period is closed. For ADUs and duplexes, this is most often done by manually reading the submeter. The tenant can take a photo of the water meter or American Submetering can provide an automated solution for a montly fee.
Once the submeter is installed and monthly readings are being collected, water bills can be generated manually by the owner/landlord or automatically by American Submetering with some additional equipment. It's important to ensure that the timing of the readings match with the water purveyor bills to generate accurate bills for tenants.
The most important part of submetering water is making sure to educate tenants about how the submetering system works and how the bills are generated. This ensures they understand how their water usage is being tracked and billed and can also help encourage them to conserve water.
We also recommend you check with your local state on any legal or lease requirements or addendums that may be required for charging tenants water.
Submetering an ADU allows owners to accurately track water usage and bill tenants based on actual usage. By following these steps, owners can ensure that their submetering system are set up correctly and functioning properly.
In some states, submeters need to be tested and registered with the state or a local water authority prior to installation. This ensures that the submeter is recognized as a valid measuring device and that the readings taken from it are accurate. The registration process may vary depending on the local water authority, so it's important to check with them for specific requirements.