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Leaks, pipes and water pressure

Your water meter is a leak detector you already own, and it will tell you in twenty minutes whether you have a leak at all.

The twenty-minute test that comes before everything else

If you suspect a hidden leak, do not start guessing at walls. Turn off every tap and water-using appliance, read the meter, wait, and read it again. If the reading has moved with nothing running, water is going somewhere. Most meters also have a small leak-indicator dial or star that turns on very low flows, which is more sensitive than the digits.

That test also localises the fault. Once you know there is a leak, close the stop tap at the meter and repeat: if the meter stops, the leak is on your side of the stop tap and it is yours; if the meter keeps moving with the stop tap closed, the leak is between the meter and the main, which is usually the water authority's responsibility rather than yours.

Low pressure is a different question, and the first thing to establish is whether it is everywhere or in one place. Everywhere and on both hot and cold points at the main, a pressure limiting valve, or the supply. One fixture only is an aerator, a filter or a partly closed isolation valve. Hot only is a hot-side blockage or the system itself — see hot water faults.

Pipes that bang when a tap or washing machine shuts off is water hammer: moving water stopped suddenly with nowhere for the shock to go. It is not cosmetic — sustained hammer loosens joints over time.

Know where your stop tap is before you need it. The single most useful thing in a burst pipe is being able to shut the water off in under a minute, in the dark, without looking for a tool.

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Sources

What this page explains is based on these official sources. If you check one and it does not match what you read here, send it to us and the article gets corrected.