Water meter

Position and reading[edit]

Meters are installed either in an external chamber near the boundary, alongside or close to the external stopcock, or internally on the supply pipe where it enters the building. Modern meters commonly carry a fine-resolution indicator, a small dial or star wheel, that turns visibly at flow rates far below those the main register resolves. That indicator is what makes the meter useful for finding small continuous losses.

The standing test[edit]

The basic test is to close every outlet in the property, note the meter reading or watch the fine indicator, and wait. Continued registration with nothing drawing water means water is leaving the system somewhere.

Closing the internal stopcock and repeating the observation then divides the problem. If registration stops, the loss is inside the property; if it continues, the loss is on the buried supply pipe between the meter and the building. This single step decides whether the subsequent investigation is an internal plumbing survey or an underground one, and it costs nothing.

Two things commonly confound it: automatic fills such as a cistern, a water softener regenerating, or an irrigation controller, which draw water without anyone using an outlet; and a passing internal stopcock, which lets water past when it is supposedly closed and makes an internal leak look like an external one. ADI Leak Detection's published water mains work begins from this test.^[2]

Meters and leak allowances[edit]

Because a metered customer pays for water lost through a leak, an unexplained rise in a metered bill is frequently the first indication that a leak exists at all. Many water undertakers operate discretionary leak allowance schemes that adjust charges once a leak has been found and repaired, and separately offer a first free or subsidised repair on a supply pipe. Both are company policy rather than statutory entitlement, and their terms vary between undertakers.^[1]