Installing a sub-meter is a convenient way to save money if you have a large property. In most homes with water and sewer, the sewer rate is charged based on the amount of water consumed; this includes charges for water that does not even go down the drain, notably water from the garden hose. Owners of homes with large properties or pools can benefit from installing a sub-meter. A sub-meter will account for the water used by the garden hose so you will not incur sewer charges for that water.
Go to the local building department and obtain a plumbing permit for a sub-meter installation. You will be required to pay a permit fee that varies widely by municipalities. Expect charges to be around £65 to £130.
Call your local water department and ask for the location to pick up a sub-meter. Take your permit to the water department and pay for a sub-meter.
Contact a licensed plumber and have them install the sub-meter. Only a licensed plumber can install the sub-meter or it will not pass inspection.
Contact the local water department and ask for an inspection for your sub-meter installation. Once inspection passes, the water department will modify your account so it takes into account the sub-meter installation.
Contact your local building department and have them inspect your sub-meter installation. In some counties the inspection from the water company is good enough, but most will require both inspection from the building department and the water company.
The installation process can cost around £650. Make sure you consume enough garden hose water to make the sub-meter installation worthwhile.
Do not attempt to install the sub-meter yourself or you will be forced to remove it and have it reinstalled again by a plumber.