Find your problem, and what fixes it

Plenty of leaks show up as nothing you can point at — a bill that has climbed, a meter that turns with every tap shut, a boiler topped up more often than it used to be, a smell of damp with no stain. Those are still leaks, and they are the ones worth finding early, because the damage is happening somewhere you cannot see it.

The quickest thing you can do yourself costs nothing: turn every tap off, find the meter, and watch the dial for ten minutes. If it moves, water is going somewhere. That one reading tells an engineer more than a description of the damp patch does.