How to Find a Hidden Water Leak When You Are on Well Water

On a private well there is no water bill to warn you about a hidden leak. Here is the pump test that finds one, and the three things it usually turns out to be.

On town water, a hidden leak eventually announces itself. The bill arrives, it is triple what it should be, and you start looking. Most of Virginia’s Eastern Shore does not get that warning. The water comes out of your own well, nobody meters it, and a split fitting under the floor can run for months without a single piece of paper telling you.

So the bill is not your alarm out here. The pump is.

The short version. If your well pump kicks on when nobody is using water, water is going somewhere. Shut the house off at the main, listen again, and you will know whether it is inside the house or out at the well.

The test that works on a well

This takes about twenty minutes and costs nothing.

• Turn off every fixture, and the icemaker and the washing machine with them. Tell the household not to touch a tap.
• Stand where you can hear the pump or the pressure tank. Wait. A system with no leak should sit silent for hours.
• If it kicks on, find the main shutoff where the line comes into the house and close it.
• Listen again for another fifteen minutes.

If the pump keeps cycling with the house isolated, the leak is between the well and that valve: the buried supply line, the pitless adapter, a bad check valve, or a pressure tank that has lost its air charge. If the pump goes quiet, the leak is inside, past the shutoff, and it is worth finding before it finds your subfloor.

On a town system, do the same thing with the meter. Note the reading with everything off, wait an hour, read it again. If it has moved, water is escaping somewhere between the meter and your fixtures.

What it usually turns out to be

In the houses we work on, hidden leaks land in a short list of places, and almost all of them are under the floor rather than in a wall.

• Under-home piping. Most Shore houses sit over a crawlspace instead of a basement, and that is where we find the majority of them. A pinhole in copper or a cracked fitting drips onto the ground, so there is no stain on a ceiling to tip you off.
• The line from the well to the house. Buried, usually plastic, and often decades old. A leak here runs into the yard and looks like nothing until you notice one patch of grass that stays green through a dry August.
• Hose bibs and outdoor spigots. A freeze split you never saw, leaking behind the siding every time the pressure comes up.
• The water heater. A tank seeping at the bottom seam looks like condensation for a week, then does not.
• A toilet that is running quietly. Not glamorous, and not cheap to ignore. A flapper that does not seat lets the tank refill over and over, which reads exactly like a leak on a pump.

The thing that is not a leak

Before anyone starts cutting, rule out the pump system itself. A pressure tank that has lost its air charge makes the pump switch on and off every couple of minutes, and homeowners read that as a leak every time. So does a failed check valve, and so does a pressure switch drifting out of adjustment.

The house shutoff test above is what separates the two. If the cycling stops when you isolate the house, you have a plumbing leak. If it keeps going, start at the well pump, tank, and switch instead. It is a cheaper problem to have, and it is worth ten minutes of checking before you go looking for a leak that is not there.

Why a crawlspace leak costs more than the pipe

A leak under a floor does not stay a plumbing problem for long. The water goes into the ground under the house, the humidity under the whole floor comes up with it, and the damage shows up as soft boards, sticking doors and a musty smell in a room that is nowhere near the actual leak. By the time the floor tells you, the repair has a subfloor and sometimes a mold bill attached to it.

That is the real argument for chasing down a pump that cycles. The pipe repair is the small number. What it turns into if you leave it is the big one.

Empty houses are where this gets expensive

The Shore has thousands of houses that sit empty for most of the year: summer places, family houses nobody has sold yet, rentals between seasons. A leak in an occupied house gets noticed in days. A leak in an empty one runs until somebody happens to stop by.

If you own one, shut the water off at the main when you leave, and ask whoever keeps an eye on the place to look under the house every few weeks rather than only at the thermostat. If you rent it out, a tenant who mentions the pump running at night is doing you a favor, so treat it as one.

What finding it actually involves

When you call us, the first job is not repair, it is location. We isolate the system and watch how it behaves under pressure, then narrow it down with listening equipment, which picks up the sound of water escaping through a floor or a slab. Thermal imaging finds a hot water line by the warm track it leaves, and the wet area around a cold one. For a leak on a drain rather than a supply line, a camera goes down the pipe and we locate the fault from the surface.

The point of all of it is to open one spot instead of several. That is also why we price it separately: locating a hidden leak typically runs $200 to $500, and the repair is quoted once we can see what failed, so you are never paying for exploratory demolition you did not agree to. The full price ranges are here, from an accessible supply repair at $250 to $650 up to a slab reroute at $1,500 to $4,000.

When it is not a slow leak any more

If water is running now, this is the wrong article. Shut the house off at the main, cut the power to any wet area, and read what to do when a pipe bursts while you wait. We take urgent calls seven days a week, 8:00am to 9:00pm, and the price is the same in the evening and at the weekend as it is on a Tuesday morning.

Questions We Get Asked About Finding a Hidden Leak

Get it found

If the pump is telling you something, we will find out what. See leak detection for how we locate it, water leak repair for what happens next, or request service and tell us what you are hearing.

Written by the team at Shoresteady Plumbing, Temperanceville, Virginia. Master plumbing licensed in Virginia and Maryland. Prices shown are typical ranges for the Eastern Shore, not a quote. Your written estimate is the only number that binds either of us.

More from the Shoresteady Plumbing blog

Home Maintenance

How Much Does a Plumbing Maintenance Plan Cost on Virginia’s Eastern Shore

Maintenance plans on the Shore run $150 to $350 a year. What the visit should include, what it prevents, and who genuinely does not nee...

Home Maintenance

Walk-In Shower or Keep the Tub: What the Plumbing Side Involves

Before you decide between a walk-in shower and a tub, it helps to know which parts of the job are plumbing, which are not, and where th...

Pipes and Leaks

What to Do When a Pipe Bursts Before the Plumber Arrives

Six things to do in the first five minutes, in order, all of them within reach of one person with no tools. What you do now decides how...

Reading about it is one thing, fixing it is another

Tell us what is going on and we will get you on the schedule. Written estimate before we start, and a 2-year workmanship guarantee on every job.