Household water leaks in Hertfordshire: the four leaks we find most

Nearly every water leak call we take from Hertfordshire comes down to one of four problems: a buried supply pipe, a central heating circuit, an underfloor heating loop, or a bathroom leak showing on the ceiling below. The symptoms overlap, so people often chase the wrong one for weeks before anyone looks properly.

This page sets out the four, the signs that separate them and the quick checks you can do at home in Hertford, Welwyn Garden City, Hoddesdon or Ware before you ring anyone. Then it explains how each type is pinpointed without ripping the house apart, and which page on this site to go to next.

Which of the four do you have

Start with the meter and the boiler, because between them they tell you most of it. If the water meter turns with every tap off, water is leaving the mains side: supply pipe or a cold water pipe inside the house. If the boiler pressure keeps dropping and you keep topping it up, the heating circuit is losing water, which includes underfloor heating.

If the meter is still and the boiler holds pressure, but there is a damp patch on a ceiling or a wall, the leak is on something that only runs when it is used: a shower tray, a bath seal, a waste pipe or a toilet. These are bathroom leaks, and they leave the meter alone because the water is going down the drain route, just not inside the pipe.

• Meter turns, boiler fine: supply pipe or cold pipework
• Boiler pressure drops, meter still: central heating or underfloor heating
• Warm patch on the floor, pressure drops: underfloor heating loop
• Ceiling stain below a bathroom, meter still: bathroom or waste leak
• Wet pavement or drive, meter still: possibly the water company's pipe

1. The supply pipe under the garden

The supply pipe runs from the boundary stop tap, usually in the pavement, to the kitchen. In the older parts of Hertford, Ware and St Albans it is often still lead or galvanised iron, and in the chalk it corrodes until it splits. In Welwyn Garden City and Stevenage the pipe is more often plastic that was nicked during a drive or extension and has finally let go.

The water goes into the ground and you see nothing, which is why the first sign is normally a high bill or a letter from Affinity Water, who supply most of the county including Hertford, Ware, Hoddesdon and Welwyn Garden City. Thames Water take the sewerage, so a drain problem comes from them instead.

This leak is found with acoustic listening. With the pipe under pressure, a ground microphone follows the route and the noise peaks over the hole. The drive is opened at that one spot. If the route is unknown it is traced first, so there is no guessing at where to dig.

2. Central heating

A combi or system boiler that needs topping up every few days has a leak somewhere on the heating circuit. If no radiator valve is dripping and the boiler itself is dry, the leak is on a pipe you cannot see, most often under a ground floor. In the 1950s and 1960s houses across Stevenage, Hatfield and Welwyn Garden City the pipes were laid in the concrete screed, and they corrode from the outside.

The damage is slow. Heating water carries inhibitor and a little rust, and it works into the screed and up into the skirting over months. By the time a dark patch shows at the bottom of a wall the leak has usually been running a long season. Timber floors in the Victorian terraces around Hertford and Ware hide it just as well.

Charlie pressure tests the circuit to confirm it, then uses the thermal camera with the heating hot to see the pipe runs through the floor and the wider warm bloom where the water is spreading. For an exact point, the circuit is drained and filled with tracer gas, and the detector follows it to the break.

3. Underfloor heating

Underfloor heating is common in newer houses and extensions around Hertford, Hoddesdon and St Albans, and the leak is almost always in one loop. The boiler pressure drops, part of the floor is warmer or cooler than the rest, and sometimes tiles lift or laminate swells. Each loop is isolated at the manifold to find the one that will not hold pressure.

The pipe itself rarely fails. The problem is usually a nail or screw through it from a door threshold or a skirting fixing, or a kink or joint from the original installation. Because the pipe is in the screed under tiles, nobody wants to guess where to dig.

The thermal camera is the tool for this. With the loop warm, every pass of the pipe shows through the floor, and the leak appears as a blurred patch where the warm water has spread. Tracer gas confirms the exact point. One tile or one board comes up, not the floor.

4. Bathroom and ceiling leaks

A stain on the living room ceiling under the bathroom, a bubbling patch on the hall wall, or a damp smell on the landing is nearly always a bathroom leak. Because the water only runs when the shower, bath or basin is used, the meter and the boiler give no warning, and the stain comes and goes with use.

The common causes are a failed seal round the shower tray or bath, a cracked grout line that lets water behind the tiles, a loose waste connection under the bath, a shower valve leaking inside the wall, and a toilet pan connector weeping at the back. Any of them can take weeks to show through a plasterboard ceiling.

Charlie works through the fittings one at a time, running each for a set time and watching with a moisture meter and the thermal camera from below. That shows which fitting leaks and which pipe or seal carries the water. Only the panel or tile that needs to come off does.

What to do today, before anyone visits

Do the meter test: everything off, read the meter, wait an hour, read it again. Then do it again with the internal stop tap closed to split outside from inside. Note the boiler pressure in the morning and again at night. Photograph any damp patch with a coin next to it so you can see if it grows.

If the leak is heating, turn the boiler off rather than keep topping it up, because every top up is fresh water into the floor. If a ceiling is bulging, put a bucket under it and pierce it with a screwdriver to let the water out before the plasterboard comes down on its own.

Then ring. Charlie covers Hertfordshire from Haverhill, about 45 miles from Hertford, and can usually book you in within 24 to 48 hours. The visit runs on no find, no fee and you get a written report for your insurer. Recent jobs include Bengeo, Hertford Heath, Great Amwell, Hoddesdon, Codicote and Bernards Heath in St Albans.

Questions people ask