Hidden Leaks in Antrim — Signs and the Stopcock Test

What does a hidden leak look like before it looks like a flood?

Small and boring. That is the trap. The signs, in rough order of how often they appear:

• A damp patch on a wall, floor or ceiling that slowly grows — or dries and comes back.
• A ceiling stain with a brown tide-mark edge, usually under a bathroom.
• A musty smell in one room that airing never quite shifts.
• The hiss or tick of running water when every tap and appliance is off.
• Boiler pressure that keeps dropping between top-ups.
• If your home has a water meter — most in Northern Ireland do not — readings creeping up with no change in habits.

Any one of these in an older house near the town centre deserves extra respect: pipework of several ages meets under those floors, and the joints between eras are where quiet leaks like to start.

How does the stopcock test actually work?

This is the honest, no-kit version of leak detection, and it answers the only question that matters first: is the water escaping on your side?

1. Turn everything off. Every tap, the washing machine, the dishwasher, the heating. The house should be using no water at all.
2. Close the stopcock. Clockwise until it stops — the same valve from the burst pipe drill.
3. Watch and listen. If the damp patch stops growing or the hiss goes silent, the leak is on your own pipework, downstream of the stopcock. That is a plumber's job, and you have just saved them an hour of hunting.
4. Have a meter? Use it. With the stopcock open again and everything still off, read the meter, wait 30 to 60 minutes without using a drop, and read it once more. Any movement means a leak on your side. No meter — the usual case here — means the watch-and-listen result is your evidence.
5. Nothing changes with the stopcock shut? Then the water may be coming from somewhere else entirely: the supply pipe before the stopcock, a roof or gutter fault, or condensation. Say exactly that when you ring — it changes who should look at it.

Boiler pressure keeps sagging — is that a hidden leak?

Very often, yes. A sealed heating system is a closed loop; if the gauge keeps falling, water is leaving the loop somewhere. Sometimes that is a weeping radiator valve you can see. Just as often it is a pinhole in a pipe under the floor, quietly wetting the joists every time the heating runs — which is why these leaks show up in heating season and vanish in summer. The rule from the boiler drill applies double here: one top-up through the filling loop is maintenance, but topping up every week is watering a leak. Stop refilling and have the loop traced before the first ceiling stain appears.

When does a hidden leak stop being a watch-and-wait job?

Four signs move this from "monitor it" to "act now": water anywhere near sockets, fittings or the consumer unit; a ceiling that is sagging or bulging; a patch that is visibly spreading while you watch; or a floor that has gone warm and damp, which points at a hot pipe leaking below. The response is the burst pipe opening, not the leak-watching one — stopcock off, electricity off in the affected area if you can reach the board dry, and stand clear of any badly sagging ceiling. Then ring, whatever the hour. A leak that has reached the electrics or the structure has stopped being hidden and started being an emergency.