Dripping overflow pipe repair across London

A dripping overflow pipe outside the property is one of the most reliably misdiagnosed faults in domestic plumbing. The overflow is a warning pipe, not a fault in itself, and its job is to tell you the cistern or tank it serves has overfilled. The cause is upstream, and on London property it is one of three things in roughly this order: a perished WC fill valve dribbling past its seat, a failed cold-water-storage-tank ballcock in the loft on a traditional gravity-fed system, or a failed pressure-relief drip pipe from a sealed-system combi or unvented cylinder where the safety valve has lifted and is not reseating.

Our visit always starts with an end-to-end trace of the pipe back to the cistern or tank it serves. For a WC overflow the fix is a Fluidmaster PRO, Torbeck quiet-fill, or Siamp Compact diaphragm fill valve fitted in place of the old unit. For a loft-tank overflow the fix is a Part 2 ball-valve or a modern equilibrium valve set to BS6700 cold-water-storage geometry. For a sealed-system pressure-relief drip, the cause is usually a failed expansion vessel or a passing safety valve and the repair scope is in the boiler service category. Every overflow visit closes with verification that the warning pipe has run dry and stayed dry.

How we deliver

No surprises, no upselling. The exact path every job follows.

1. 1
   Trace the overflow pipe to its source
   We identify which cistern, tank, or appliance the warning pipe serves by following the run back from the external outlet. First-floor level usually points to a bathroom WC, eaves level points to a loft tank, and a copper or stainless drip pipe near the boiler points to a sealed-system safety valve.
2. 2
   Confirm the failure mode at source
   Cistern lid lifted or loft tank inspected. Water level checked against the warning-pipe overflow datum. Fill valve operated to confirm whether the diaphragm is perished, the seat is pitted, or the float arm is sticking.
3. 3
   Isolation at the service valve
   Supply to the failed unit isolated at the in-line service valve, or at the BS1010 stop-tap where no isolator is fitted. We fit a new quarter-turn isolator as part of the visit where one is missing.
4. 4
   Failed valve removed
   Cistern drained, supply tail disconnected, and the failed fill valve or tank ball-valve lifted out cleanly. Back-nut washers and the wall around the seat checked for damage before any new unit is offered up.
5. 5
   New WRAS-approved unit fitted
   Modern Fluidmaster PRO, Torbeck quiet-fill, or Siamp Compact diaphragm valve installed on a WC cistern, or a Part 2 ball-valve or equilibrium valve set to BS6700 geometry on a loft tank. Type AG air-gap to BS6730 preserved as standard.
6. 6
   Calibrate the water level
   Service valve reopened, cistern or tank allowed to fill, and the float arm or screw adjusted so the water sits a clear 20mm below the warning-pipe overflow. This is the difference between a quiet system and a system that drips every time someone has a bath.
7. 7
   External overflow verified dry
   The external warning pipe is inspected after a full cycle to confirm it has stopped dripping and stays dry under live operation. We do not leave the visit until the external outlet is verifiably dry.