Plumber Cannot Find the Leak? What a Leak Survey Adds

Plumbers work on what is in front of them. They check the visible pipework, the fittings under the bath, the joints behind the toilet and the connections to the boiler, and they fix what they find. That covers a great many leaks. The ones that remain are hidden by design. A pipe buried in a screed, a heating run in a ceiling, a supply pipe under a hall floor, a joint inside a wall chase. No amount of looking reveals those, and a plumber who says they cannot find it is being straight with you.

A leak detection survey works from the other direction. Instead of looking for water, it measures where water is going and listens for it. A thermal imaging camera shows the warmth of a hot or heating pipe through plaster and floor finishes, and the cold shape of a wet area. A Sewerin Aquaphon ground microphone hears water escaping under concrete and tiles. Nitrogen pressure tests show which circuit is losing and roughly how fast. Hydrogen tracer gas in a drained pipe finds the hole in a plastic pipe that makes no sound. A borescope looks into voids through a small hole.

The most useful thing you can bring to the survey is a list of what has already been checked. If the plumber has pressure tested the heating, replaced a bath seal or looked under the kitchen units, say so, and bring any photographs. It stops the same ground being covered twice and narrows the search before the kit comes out of the van. Tell us too when the leak is worse: after baths, when the heating runs, or all the time. Those patterns point at a system before a single reading is taken.

Opening a floor or a wall on a guess is where cost escalates. Every wrong opening has to be made good as well as the right one. A survey replaces guesses with a marked point. A fixed price is agreed before we start, and most home surveys take between two and four hours. If a leak cannot be located non-invasively, we say so and explain what we would do next rather than keep opening things up. Tracer gas is a detection method only and is not gas-safety work. If you smell gas, leave the property and call the gas emergency number.