Kitchen Leak Under the Sink, Units or Floor?

A kitchen packs a lot of water into a small space. The sink has hot and cold feeds, a trap and a waste. The washing machine and dishwasher have their own supply valves, inlet hoses and drain hoses pushed onto spigots under the sink. A boiler is often on the wall or in a cupboard. Under the floor, heating pipes feed the radiators and, in extensions, cross the room in the screed. All of it is behind plinths, inside cupboards or under the floor. A leak shows only when water reaches the front of the units, lifts the floor or appears in the room next door.

The signs are usually small at first. A plinth that has swollen or gone dark at the bottom. A cupboard base that feels soft under the sink. Laminate or vinyl lifting at the edge of the units. A warm patch on the floor in front of the cooker or the sink with the heating on. A musty smell when the dishwasher door is opened. A boiler that needs topping up. In kitchen extensions on a solid floor, a heating pipe laid in the screed can leak for a long time with nothing to see but a rising bill and a warm floor.

Appliance connections and wastes are tested first because they fail most often. The plinths come off and each valve, hose and spigot is checked while the appliance fills and drains. A moisture meter maps the base of the units. The thermal camera then scans the floor and the walls behind the units for heating pipes and the warmth of escaping hot water. Where a pipe is quiet, we drain it and introduce hydrogen tracer gas, sampling through a plinth gap or a small opening in a worktop. This is a detection method, not gas-safety work. If you smell gas, leave the property and call the gas emergency number.

Once the leak is pinpointed, we mark it, photograph it and record the readings in your written report. A failed hose, valve or waste can often be replaced on the same visit. A pipe under the floor is reached through one small opening at the mark, by hand, and repaired in copper or barrier pipe. Units are only removed when the opening falls directly beneath them, and we say so before starting. Where the leak has damaged units or the floor, trace and access cover on most buildings policies pays for locating it and making good the opening. Escape of water cover deals with the damage.