lxv : Pine for a ballcock
The sinister whisper of water secretly running in a pipe at midnight.
Visit the taps; put ear to the inside of the washing machine; listen at the boiler plumbing; stand in the cupboard below the bathroom to inspect the ceiling; pull down the loft ladder and creep full of arachno-dread around the header tanks; check for wet patches; listen; take a torch to the illegible water meter and watch the wheels still creeping, creeping, creeping round.
The downstairs toilet. An almost invisible and silent rill of water running into the bowl hours after the last flush. And it has one of those clever modern bolted together multi-flush siphoning thing cisterns which take actual skill to adjust, so I will have to Get Someone In. Thus I lay crossly in the dark, pining for a simple old ballcock.