Quick answer
A water bill that jumps with no change in use usually means a leak. Turn off every tap and water appliance, read the meter, wait two hours without using water, and read it again. If the number moved, water is leaking. Check toilets first with a few drops of food coloring in the tank, then faucets, the water heater relief line, irrigation and outdoor spigots. A leak you cannot find is a job for a plumber with leak detection equipment; HomeWyse puts leak detection at about $241–$292 per leak. Call (888) 217-6781 to reach a plumbing company taking calls in your ZIP.
Follow the short menu, then your 5-digit ZIP. The line goes quiet for a few seconds while it connects; stay on. If it does not connect, call once more: companies taking calls change minute to minute.
Written & reviewed by Marcus ReedIICRC WRT
Reviewed November 4, 2026· Next review May 2027
A water bill that jumps without a change in how the house uses water is one of the earliest signs of a leak, often before any stain or damp spot shows. EPA WaterSense estimates household leaks can waste nearly 10,000 gallons a year in an average home, and about 10% of homes have leaks that waste 90 gallons or more a day. The good news is that the meter can tell you in two hours whether a leak exists, and most leaks are in a short list of places.
Step 1: Rule Out the Bill Itself
Compare gallons or units used, not the dollar amount, against the same month last year. A rate increase, a new sewer fee, an estimated reading followed by a catch-up reading, or summer watering can each explain a higher bill with no leak at all.
Step 2: The Meter Test
- 1Turn off every faucet, the washer, the dishwasher, the ice maker and any irrigation.
- 2Find the meter, usually in a box near the street, in the basement or where the main line enters.
- 3Note the reading, or watch the small triangle or dial that turns with low flow.
- 4Use no water for two hours, then read it again.
If the reading moved, water is escaping. To narrow it down, close the main shutoff at the house and watch again. If the meter still moves with the house valve closed, the leak is in the service line between the meter and the house. See main water line leak.
Talk to a plumber about this
One call reaches a plumbing company taking calls in your ZIP.
Step 3: The Usual Suspects, in Order
| Where | How to check |
|---|---|
| Toilets | A few drops of food coloring in the tank; color in the bowl after 15 minutes without flushing means a flapper leak. See toilet keeps running |
| Faucets and shower heads | Drips after the tap is off; see faucet dripping when off |
| Water heater | Water from the relief valve pipe or around the base |
| Irrigation | Soggy patches, a zone that will not shut off |
| Outdoor spigots | Drips or a wet wall inside below the spigot |
| Under the slab | Warm spots on the floor, sound of running water; see slab leak |
When It Is a Job for a Plumber
If the meter moves but every fixture checks out, the leak is hidden: in a wall, under the slab or underground. A plumber with leak detection equipment uses pressure tests, acoustic listening and thermal imaging to find it without opening walls at random. HomeWyse puts leak detection at about $241–$292 per leak, before the repair. See leak detection.
Ask your water utility, too: many offer a leak adjustment on the bill once the leak is repaired, and they will want the plumber's invoice.
The Call
Call when the meter test shows a leak you cannot find, when the meter moves with the house valve closed, or when you see warm spots or dampness in a floor or wall. (888) 217-6781 connects you to a plumbing company taking calls in your ZIP. Follow the short menu, enter your 5-digit ZIP and stay on while it connects; if it does not connect, call once more, because the companies taking calls change minute to minute.
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Frequently Asked Questions
Why is my water bill so high all of a sudden?
A running toilet is the most common cause, then a dripping faucet, an irrigation leak, a water heater relief valve or a leak in the service line. A rate change or an estimated reading can also do it, so compare gallons used, not dollars.
How do I check my water meter for a leak?
Turn off all water use, note the reading or the small leak indicator, and check again after two hours. Any movement means water is leaving the pipes.
Can a running toilet raise my water bill?
YesEPA WaterSense notes a leaking toilet can waste a large amount of water a day, and because the water goes down the drain silently it is easy to miss for months.
How much does leak detection cost?
HomeWyse puts professional leak detection at about $241–$292 per leak, before the repair itself.
Sources
Methodology: How we source and verify data · Report an error
Disclaimer: HearthDry is an independent educational resource. This article is for informational purposes only and does not constitute professional, legal, or insurance advice. Consult licensed professionals before making decisions about your property or insurance claims.
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