
Why Is My Boiler Leaking Water From Underneath
A boiler leaking water from underneath is almost always caused by one of four problems: the pressure relief valve releasing excess system pressure, a faulty or loose filling loop, a failed expansion vessel, or a pinhole leak in the heat exchanger or internal pipework. Most causes are not safe to fix yourself and need a Gas Safe registered engineer. Switch the boiler off, isolate the water supply if you can reach the isolation valves, and book a callout before any visible damage spreads to the wall, floor or electrics.

