Water Bill Up With Nothing Running? Leak Detection in Potomac, MD Starts at the Meter

Is it a leak or just high use? Start with the meter

A water bill that jumps can mean a leak, a seasonal change in use or a billing estimate. The way to tell is the water meter, because a meter reports what actually passed through, and it keeps reporting at night when you are not looking.

Pick a time when everyone is away or asleep. Close every faucet and make sure the dishwasher, washing machine, ice maker and irrigation system are idle. Then read the meter before bed and again in the morning, writing both numbers down.

• If the two readings match, nothing is leaking, and the bill has another explanation.
• If the reading moved with every fixture idle, water is leaking somewhere on your side of the meter.
• Many meters have a small low-flow indicator, a dial or triangle that turns with even a tiny flow. If it is moving when nothing is on, treat that as a leak.
• Read the meter, but never turn or adjust it. It belongs to the utility.

A meter that moves tells you a leak exists. It does not tell you where. The next questions are whose side of the line it is on and whether it is inside the house.

Inside the house: toilets, fixtures, then hidden lines

Most household leaks are simple ones. Check the likely culprits before paying for detection equipment, because a small repair is a better outcome than a long search.

1. Toilets: add a few drops of food coloring to the tank and wait 15 minutes without flushing. Color in the bowl means a leaking flapper.
2. Faucets and supply lines: look under sinks and behind toilets for drips, rust or a damp cabinet floor.
3. The water heater: check the base and the relief valve line for moisture or mineral crust.
4. Appliance hoses: inspect the washing machine and dishwasher connections.
5. Walls and ceilings: look for stains, bubbling paint or warm spots, especially under bathrooms.

If all of these check out and the meter still moves, the leak is probably in a concealed line, in a wall, a ceiling or under a floor. That is when detection equipment earns its keep.

Leaks that are not a plumber's job, and leaks with their own page

A pool or spa that loses water may have a leak in the shell or in its own plumbing, or it may only be evaporating. The usual bucket test is simple. Set a bucket on a pool step, fill it to the same height as the pool, and mark the water level inside the bucket and on the pool wall. After a day, compare: if the pool dropped more than the bucket, the pool is leaking and not just evaporating. Repeating the test with the pump off helps show whether the loss is in the shell or in the pump and return lines. Say on the call that the water loss is at a pool or spa, since not every plumber works on them.

A leak inspection can also be a plain assessment: the plumber checks fixtures, pressure and the water meter, then reports what was found and what to do next, even when no active leak turns up.

Not every wet spot is a plumbing leak. A stain on a ceiling can come from a roof, a window or a gutter. A damp basement wall can come from outside grading or groundwater. A roofer, window specialist or waterproofing contractor handles those, and a plumber's detection work will rule out the plumbing quickly so you can call the right trade.

Some leaks have their own pages. A smell of gas belongs with gas leak safety, and the first call is to the utility. A line that has already split is covered under a pipe that has split. Floor leaks in slab-on-grade rooms are discussed on the slab leak repair page.

Early warning signs, and what ignoring them costs you

Small leaks announce themselves long before they flood. Catching them early limits damage to the structure and to your budget.

• A water bill that climbs without a change in use.
• The sound of water running when everything is off.
• A musty smell, peeling paint or stained drywall near a bathroom or kitchen.
• Warm spots on a floor, or damp carpet that never quite dries.
• Pinhole sprays or green crust at copper joints. Repeated pinholes suggest the pipe itself is aging, so pinhole leaks and repiping is worth reading.

A slow leak left alone soaks framing and insulation, supports mold and can ruin finishes. If water has already spread, drying out the wet area is the next job after the source is fixed. For what detection and repair cost, the leak detection price ranges use wide ranges rather than quotes.

Finding a leak in a store, office or multi-tenant building

In a business, a leak often shows up first as a bill. WSSC offers a One-Time High Bill Adjustment for single-unit commercial properties. To qualify, the average daily use has to be at least three times the comparable figure from the previous season, and the cause has to be unidentified. WSSC says this adjustment does not require a plumber's invoice or a permit, but it does ask for two meter check readings taken at least ten days apart. WSSC Customer Service is at 301-206-4001.

Repairs to underground water lines are a separate matter. WSSC requires them to be done by a registered, licensed WSSC plumber, so a leak found between the meter and the building needs one. Large commercial meters and several tenants on one meter make the search harder than in a house, and the search runs better when it starts with a clear picture of who uses water and when.

• Ask the building manager for the meter location and the last two or three bills.
• Shut off every fixture and process that uses water, then watch whether the meter still turns.
• Tell the plumber about irrigation, cooling equipment, floor drains and any sprinkler connection.
• Note which tenant or unit sits on the meter, since a shared line widens the search.
• Keep the plumber's written finding for the property owner and for any bill adjustment request.

The page names single-unit commercial properties. A building with several tenants may need to ask WSSC how the adjustment applies.