Leak Detection
Pinpoint a hidden leak using acoustic listening, thermal imaging and pressure tests.
Homeowner guide
Finding a Hidden Water Leak at Home in Commerce City, CO
Most house leaks leave clues. Start with the meter, then check toilets, the water heater, sinks and appliance hoses. If the meter still moves with everything off, the leak is somewhere you cannot see.
By the Mile High Express Plumbing team · published
Start with the water meter
Turn off every tap and appliance, including the ice maker and the sprinkler controller. Find the water meter, which is usually in a box near the street or the property line, or in a basement. Look for a small triangle, star or dial that spins when water is moving. Many meters have one.
If the dial moves while everything is off, water is escaping somewhere. Note the reading, avoid water for two hours and check again. A new number means a leak. For one on the utility side, the district's meter-pit line is 303-288-2646.
Check toilets with food coloring
Silent toilet leaks are the most common of all. Put several drops of food coloring in the tank, do not flush, and wait roughly fifteen minutes. Color appearing in the bowl means the flapper no longer seals.
A hissing tank or a bowl that tops itself up points to the same cause. A new flapper or fill valve is an inexpensive repair that can save a lot of water over a month.
Look at the water heater and appliances
Look under and around the water heater for moisture, rust or drips from the relief pipe. Check the washing machine, dishwasher and refrigerator hoses, since a worn hose can leak slowly behind the appliance.
Run a dry paper towel along supply lines and valves under each sink. Fabric that stays damp or a stained cabinet floor means a slow drip. A brittle braided hose is worth replacing even if it has not failed yet.
Usual leak locations and a fast test for each
Go down the list in order; each test takes only minutes.
| Location | Telltale sign | Fast test |
|---|---|---|
| Toilet tank | Hissing, or a bowl that tops itself up | Food coloring in the tank for fifteen minutes |
| Water heater | Damp base, rust streaks or a wet floor | Inspect around and beneath the tank |
| Cabinets under sinks | Warped boards or a musty cabinet | Slide a dry paper towel along each pipe and stop valve |
| Washer, dishwasher or fridge line | Wetness behind the appliance | Examine every hose and fitting |
| Meter | Dial moves while everything is off | Note the number, wait two hours, read it again |
Signs of a hidden leak in a wall or floor
Signs of a leak inside a wall or floor include peeling paint, bubbling drywall, a musty odor, warm floor patches and an unexplained rise in your bill. Hearing running water in a silent house is another.
Check ceilings below bathrooms and the walls around the water heater. A stain that grows after a shower points to a drain or shower leak. A stain that grows with no one using water points to a supply line.
Leaks outside and underground
A wet patch of lawn, a squishy spot during a dry week or a puddle that never dries can mean the buried supply line has failed. A sudden pressure drop, or a meter that keeps turning after you close the main, also puts the leak between the meter and the house.
Shut the main valve inside the house and keep an eye on the meter. If the dial stops, the leak is indoors; if it keeps moving, the leak is outdoors. A water line repair crew can locate and fix a buried pipe.
When to call for leak detection
If you have done the meter test and checked the obvious spots and the leak is still hidden, call for leak detection. Technicians use acoustic listening, thermal imaging and pressure testing to pinpoint a leak without opening large areas of wall or floor.
If the leak is under the slab, slab leak detection is the next step. Even a small leak does harm each day, and mold can begin within 24 to 48 hours once materials are wet.
What a hidden leak sounds like
Turn off the radio and the television and walk the house slowly. A hiss near a wall, a faint trickle behind a cabinet or a periodic click from a toilet tank can point to the source. Put your ear against a wall near pipes to listen.
Keep in mind that sound travels along pipes. A noise in one room may come from a pipe on the other side of the house. A technician uses a listening device to tell the difference.
Photograph and track
Take dated photos of any stain, bubble or crack and write down the meter reading each time you test. A growing stain after a rain points to the roof or a window, not a pipe. A stain that grows with the water on and shrinks with it off points to the plumbing.
This record helps a technician narrow the search, and it helps with an insurance claim later. Share the log with the technician so the search starts from your notes instead of from scratch. If you rent, email the same photos and readings to the landlord, which leaves a dated record of when you reported the problem.
Leaks that only show under pressure
Some leaks appear only when pressure is high, such as at night when demand falls. A small pinhole can seep for hours and stay dry by morning. Check the meter in the evening and again in the morning without using water.
Pressure that is higher than normal strains fittings and appliance hoses. A gauge on a hose spigot shows whether the pressure is within a safe range.
Common questions
Leak detection questions
The meter test is the best check. If the meter moves with every fixture off, a leak exists.
Yes. A running toilet or a slow underground leak can add up without a visible puddle.
Sometimes. Put your ear near pipes and appliances in a quiet house. A technician uses special equipment for hard-to-hear leaks.
Warm floor spots, running-water sounds, damp carpet or a bill that jumps are all possible signs.
Services that help
Slab Leak Detection & Repair
Find and repair a failing pipe under a concrete floor, garage slab or basement floor.
Water Line Repair & Replacement
Fix or replace the buried supply pipe running from the meter to your home.
Keep reading
Why your water bill is high
A bill that jumps usually has a findable cause. Check the meter first, then the toilets.
Running toilet fix
A running toilet wastes a lot of water. Most are fixed by a flapper, a chain or a fill valve in minutes.
Turn off the main water valve
Knowing where your main valve is and whether it works can save thousands of dollars in a flood.
Leak you cannot find?
Phone in and describe what you are seeing. We will line up a local contractor.