High water bill? How to find a hidden leak
A water bill that jumps without a reason usually means a hidden water leak somewhere you cannot see. Two quick checks tell you whether you have a leak, and the signs point to where it is.
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How do I know if I have a hidden water leak?
To check for a hidden leak, turn off every faucet and water-using appliance, then look at your water meter. If the leak indicator is spinning or the reading changes over 15 to 30 minutes, water is leaking somewhere. Toilets are the most common culprit, followed by leaks in walls, under slabs and in the line from the meter to the house.
- Watch the water meter
- Dye-test every toilet
- Look for stains and sounds
- Leak detection finds the rest
Check 1: the water meter
Turn everything off
Faucets, showers, the dishwasher, washing machine, ice maker and irrigation.
Find the meter
Usually in a covered box near the street. Look for a small dial or triangle that spins with flow.
Watch it
If the indicator moves, or the reading changes over 15 to 30 minutes, water is leaking.
Narrow it down
Close the main shutoff at the house. If the meter still moves, the leak is in the line between the meter and the house.
Check 2: the toilets
A toilet that leaks into the bowl is silent and can waste a lot of water, and it is the most common cause of a high bill. Put a few drops of food coloring in each toilet tank and wait 10 to 15 minutes without flushing. Color in the bowl means the flapper is leaking. Our guide to a toilet that keeps running covers the fix.
Signs of a leak you cannot see
Look and listen for:
- Water stains or bubbling paint on walls and ceilings
- Warm spots on a floor over a slab
- The sound of running water when nothing is on
- Musty smell or mold in a cabinet or closet
- A wet or extra-green strip of lawn
- Low pressure that was not there before
Where hidden leaks are found
In Upstate homes, the usual places are supply lines inside walls and ceilings, pinhole leaks in older copper, failing polybutylene fittings, slab leaks under homes built on concrete, and the main water line between the meter and the house. Leaks in the main line often show up as a soggy spot in the yard, and we repair them by boring under driveways rather than tearing them up.
When the meter says there is a leak and you cannot find it, leak detection uses acoustic listening, thermal imaging and pressure testing to pinpoint it, so we open one small spot instead of searching.
Hidden water leak: common questions
How much water can a hidden leak waste?
A running toilet alone can waste hundreds of gallons a day. Even a slow drip adds up over a billing cycle.
Who fixes a leak at the meter?
Your water provider handles its side of the meter. Leaks between the meter and the house are the homeowner's.
Can a leak cause a high bill without visible water?
Yes. Toilets, leaks under slabs and main line leaks often show no water inside the house.
Will my water company adjust a high bill from a leak?
Some providers offer a one-time adjustment once the leak is repaired. Ask your provider and keep the repair invoice.
How do you find a leak without tearing up walls?
Acoustic listening, thermal imaging and pressure tests pinpoint the spot, so we open only what we need to.
Ready when you are
Tell us what's going on.
A Master Plumber will find the cause, explain it in plain terms, and put your options in writing before any work starts.
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