Emergency Leak Detection in Londonderry, NH

Signs of a hidden leak, and when to call it an emergency

Slow leaks hide for months. Fast leaks announce themselves. Knowing which one you have decides whether you call tonight or tomorrow morning.

Any leak that is near electrical fixtures, soaking insulation or running down walls belongs in the emergency column. Do not wait to see if it dries.

Water meter still running or a high water bill

A meter that keeps turning when every fixture is off is the clearest sign of a leak. Shut off all taps, the dishwasher and the washing machine, then check the meter dial or the small low-flow indicator for movement. If it moves, water is escaping somewhere downstream of the meter.

From there we split the system in two by closing the main valve inside the house. If the meter stops, the leak is inside the building. If it keeps moving, the leak is on the buried line between the meter and the house.

Many Londonderry homes are on private wells and have no water meter and no water bill. For those homes the warning signs are different: the well pump cycles on and off when nobody is using water, the pressure tank loses charge quickly, or the electric bill climbs. A pressure test on the house plumbing tells us whether the loss is inside the walls or before them.

Ceiling, wall and attic leaks

Water travels. A stain on a ceiling is rarely directly below the leak, because water runs along joists and pipes before it finds a place to drop. A moisture meter and a thermal camera show the damp path, and the starting point is usually uphill of the stain.

We check supply lines, drain lines and shower pans above the stain before suggesting a roof or window cause. A roof leak will usually leave water only after rain, while a plumbing leak shows up on dry days too. Attic leaks near a water heater or a heating pipe are common in winter, when a joint can weep as the pipe expands and contracts.

Once we mark the source, the repair opens an area the size of a dinner plate and not a whole ceiling. Our burst pipe repair page explains what happens when the pipe has actually split.

Basement, crawlspace and under-house leaks

Many New Hampshire homes sit over a basement or crawlspace, which makes the underside of the house the easiest place to inspect. Wet joists, rusty hangers, a damp sill or a dripping fitting under a bathroom are all visible with a flashlight and a ladder.

The harder case is groundwater that looks like a leak. A damp basement floor after heavy rain is not always a plumbing problem. We test the supply lines first and report honestly when the water is coming from outside the house, because that fix belongs to a waterproofing or drainage contractor and not a pipe repair.

Under-house drain leaks are the second suspect. A cracked drain below a toilet or tub drips only when that fixture is used, and a dye test confirms which fixture is the source.

Buried lines, the yard and the meter box

The line from the street or the well to the house runs underground, and a leak there can go unseen for months. Warning signs include a soft or unusually green patch of lawn, a wet spot in dry weather, and pressure that drops through the day.

We pinpoint buried leaks with ground microphones that hear the hiss of escaping water, then confirm with pressure isolation. A leak at the meter box is a separate case. Water pooling in the box or around the curb stop usually means a failed fitting, and we can often replace it without digging far.

If the buried line itself has failed, the repair or replacement is covered on our water service line repair page.

Slab leaks in a basement region

A slab leak is a leak in a pipe running through or beneath a concrete floor. Slab-on-grade houses are less common in New Hampshire than in warmer states, since most homes here are built over basements. That is good news, because most supply lines run in the open where they can be reached.

Slab leaks still happen in additions, garages, finished walkout levels and some newer homes built on a slab. Signs are a warm floor, the sound of running water and a wet carpet edge. We locate the line with acoustic and thermal tools, then offer a spot repair, a reroute or a repipe, depending on pipe age.

Irrigation and pool leaks

A sprinkler zone that runs weakly or floods one corner of the lawn usually has a cracked fitting or a broken head. We check the zone valves and pressure, trace the wet line and repair the damaged piece. Winterizing the system before the first hard freeze prevents most of this damage.

Pool and spa plumbing leaks are tested by isolating each line and holding pressure. We test the supply and return lines that run between the equipment and the water, and we refer shell and liner leaks to a pool specialist.

How we find the leak without tearing things open

1. Interview and meter checkWe ask what you have seen, then test the meter or the well system to confirm that water is actually being lost.
2. Pressure isolationWe shut off sections of the plumbing and watch the gauge to narrow the search to a single run of pipe.
3. Listening and imagingAcoustic microphones, a thermal camera and a moisture meter pinpoint the spot, and a drain camera checks waste lines.
4. Marking and optionsWe mark the leak, explain the repair choices and give you a clear price before work starts.

Commercial properties with multiple restrooms or a fire line need a longer survey, which our commercial plumbing team handles.

Leak detection across Londonderry and neighboring towns

We cover all of Londonderry, from North Londonderry and Wilson to the Woodmont Commons area. We also work in Windham, Derry and Litchfield, where private wells are common and a leaking supply line shows up first as a pump that will not shut off.

Once a leak is located, the repair follows the International Plumbing Code (IPC), including approved pipe materials and correct supports.