There is a particular sound a house makes at two in the morning when everything is off and something is still running. Most people hear it, decide it is the refrigerator, and go back to sleep. Sometimes it is the refrigerator. Sometimes it is a pinhole in a copper line under the kitchen, losing a gallon an hour into the ground, and it has been doing so since spring. The difference between those two outcomes is whether anyone checked. This page is about checking.
The seven signs
- 1
The water bill went up, and nothing else did
This is the most reliable sign because the meter has no imagination. It records what passed through it. If your habits are the same and the bill is not, water is leaving the system somewhere you cannot see. Compare this month to the same month last year, since summer irrigation muddies month-to-month comparisons.
- 2
You hear water when everything is off
A hiss, a faint rush, a trickle inside a wall or under the floor. Turn off every fixture and appliance, stand still, and listen. A quiet house should be quiet. If it is not, note where the sound is loudest. That is where the search begins.
- 3
A warm spot on the floor
Walk the house in socks. Tile that is warm in one place for no reason is being heated from below by a hot-water line that has failed. This is the classic Phoenix slab leak signature, and it is the one that does damage fastest. Read about slab leaks.
- 4
Stains, damp spots, or bubbling paint
Yellow, brown, or rust-colored marks on ceilings and walls. Paint or drywall that bubbles. Baseboards that swell. Water shows itself eventually, and when it does, the leak has usually been running for a while. Remember that water travels: the stain is where it arrived, not where it left.
- 5
A musty smell
Mold and mildew need moisture, and they announce themselves by nose before they show by eye. A closet, a hallway, or a bathroom that smells damp with no obvious cause has a source somewhere behind the surface.
- 6
Low water pressure, everywhere at once
One weak shower is a fixture problem. Weak pressure at every fixture points upstream, to the main line between the meter and the house, or to a large leak somewhere in the supply. Main line detail here.
- 7
A green patch in the yard, or a soft one
In a city that gets eight inches of rain a year, a patch of grass that is greener than its neighbors is being watered by something. A soft, spongy, or sunken area along the line's route says the same thing louder.
The meter has no imagination. It records what passed through it, and it does not care what you hope the answer is.
The four-minute test you can do tonight
This is the single most useful thing a homeowner can do, and it costs nothing.
- Turn off every faucet, the ice maker, the sprinklers, the pool autofill, and anything else that draws water. Make sure no toilet is running.
- Walk to the water meter, usually in a box near the street. Lift the lid. Note the reading, and look for a small dial, triangle, or star: the low-flow indicator.
- Watch it for two minutes. If it moves at all, water is flowing somewhere with everything off. That is a leak.
- For a slow leak, note the full reading, wait an hour or two without using water, and read it again. Any change is water lost.
If the indicator moves, close the main shutoff valve at the house and check again. Still moving? The leak is in the buried line between the meter and the house. Stopped? The leak is inside. Either way, you now know more than most people who call us, and the visit will be shorter for it.
What ignoring it costs
Structure
Water weakens framing, swells subfloor, and washes out the soil under a slab. Foundations settle unevenly. Doors stick. Cracks appear. This stage is expensive.
Mold
Given moisture and a few days, mold grows behind walls and under floors. It damages the house and, for many people, the lungs. Remediation is its own industry for a reason.
Electrical
Water reaching outlets, junction boxes, or panels is a shock and fire hazard. It is also the reason we tell you to flip breakers to wet areas before anything else.
Pests
Termites, roaches, and rodents follow moisture. A leak is an invitation with the door propped open.
The bill
A leak does not take weekends. Every month it runs is a month of water you paid for and never used.
Resale
Inspectors find what owners ignored. A documented leak history that was addressed promptly is a footnote. One that was not is a negotiation.
Habits that catch leaks early
- Read the water bill, not just the amount due. Compare usage to the same month last year.
- Run the meter test once a month. Four minutes, no tools.
- Walk the house barefoot occasionally. Feet find warm spots that eyes miss.
- Look under sinks and behind the water heater when you change the air filter. Corrosion and mineral crust precede failure.
- Fix the small stuff. A running toilet or dripping faucet is a leak too, and it is the cheap kind.
- Know where your main shutoff is, and make sure it still turns. The first minute of an emergency is not the time to learn.
Questions about signs of a leak
Can I have a leak with no visible signs?
Yes, and most slab and underground leaks start that way. The bill and the meter are the only witnesses for weeks or months. That is why the meter test matters.
My water bill is high but the meter does not move. What now?
Check the bill against the same month last year to rule out seasonal irrigation, then look for intermittent users: a pool autofill, a toilet that runs only sometimes, an irrigation zone with a stuck valve. If none of those explain it, call and we will pressure test the systems.
Is a warm spot on the floor always a leak?
Nearly always. A hot-water line under the slab, in-floor heating, or a duct can warm tile, but in-floor heating is rare in Phoenix and ducts run warm only when the furnace does. A warm spot with the heater off is a leak until proven otherwise.