Can a high water bill mean a leak affecting my foundation?

Reviewed by Preston, Oklahoma foundation repair consultant · Updated 2026-10-14

In short: A water bill that climbs with no change in household use usually means a leak somewhere, and a simple two-hour meter test shows whether water is moving when nothing is turned on. Most leaks are at fixtures, but a leak in a line under a slab can wet expansive clay and push part of the floor up, which is why it matters for foundations.

What does this sign look like?

Monthly use rises and stays high, or spikes, without new people, a pool, or a change in watering. EPA suggests comparing month-to-month use on the bill to spot spikes ². This is relevant to slab-on-grade, post-tensioned and crawl space houses.

How common are household leaks?

EPA estimates that household leaks waste nearly 1 trillion gallons of water a year nationwide, and that an average household's leaks can waste more than 9,300 gallons a year ¹. About 9 percent of homes have leaks that waste 50 gallons or more per day ¹. Leaks can add about 10 percent to a water bill ².

Common sources EPA lists ¹²:

• worn toilet flappers
• faucets dripping about once per second, which can waste more than 3,000 gallons a year
• showerheads and tub spout diverters
• irrigation systems damaged by frost or freeze; a leak about 1/32 inch wide can waste roughly 6,300 gallons per month
• hidden leaks under sinks, at water heaters, and at washing machine, dishwasher and ice maker supply lines

How do you check for a leak?

If the meter moves and no fixture or irrigation leak is found, the leak may be in a buried line or under the slab. See plumbing leak detection and repair.

Why does an under-slab leak matter for the foundation?

Expansive clay swells when it gains water. Broken water or sewer pipes add moisture that can worsen swelling damage to nearby structures ³. Foundation design guidance names leaking utility lines as a source of water that can wet the soil and cause foundation heave ⁴. Building officials in expansive-soil areas point out that a plumbing leak is one way water reaches the soil under a house and causes interior movement ⁶. On the floor, this can show as a hump near the leak. The mechanism is covered in leak-induced localized heave.

Engineering repair guidance calls for testing water supply and sanitary drain lines for leaks when lifting is part of a foundation repair, and for fixing any leaks found ⁵. Oklahoma insurance treatment of leaks is covered in plumbing leaks and insurance.

Related

• Leak-Induced Localized Heave
• Plumbing Leaks Under Slab
• Slow Drains or Sewer Backups
• Plumbing Leak Detection and Repair
• Plumbing Leaks and Insurance - Oklahoma