Two terraced houses on one supply pipe
The property
A Victorian terrace near the middle of town that shares one supply with next door, splitting under the back yards to two stop taps.
The problem
Anglian Water's letter reported constant use. Neither household could find a drip indoors, even after checking every tap and cistern.
How we found it
Shutting both stop taps at once left the dial moving, which pointed at the shared length. The ground microphone tracked it under the yard, and tracer gas rose at one flagstone.
The outcome
That flagstone was lifted at the mark. The report showed both households where the leak lay, and the shared repair was quoted separately for them to agree.