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Why is my water bill so high all of a sudden?

Short answer

Compare the gallons used, not the dollars: if usage is up, the most common causes are a running toilet, an irrigation leak or schedule change, a dripping fixture or a hidden leak, and your meter's leak indicator will show which. If usage is flat but the bill is up, it's a rate increase, a sewer or stormwater charge, or an estimated reading.

Updated · Editorial team; not yet technically reviewed

Water meter and supply pipe on an outside wall

Start with the bill itself

If Gallons (or CCF) are up
Water is really being used. Run the meter test below.
If Gallons are about the same, dollars are up
A rate change, new fees, or a different billing period length. Your utility's rate page will show it.
If The bill says "estimated"
The meter wasn't read; the next actual read may correct it. Read your own meter and call the utility.
If Usage is up in summer only
Irrigation and pool top-ups. Check controller schedules and look for wet zones.

Find where the water went

  1. Meter test

    With all water off, watch the meter's leak indicator for 15 minutes. Movement means a leak. Full steps are in signs of a hidden leak.

  2. Toilets first

    Dye test every tank. A flapper leak is the single most common cause of an unexplained high bill.

  3. Outside

    Hose bibs, irrigation zones, pool autofill and the backflow device on the irrigation line.

  4. Appliances

    Water softeners stuck in regeneration and leaking water heater relief valves both waste water quietly.

Typical culprits

  • Running toilet

    Most common

    Tell: Dye test or refill sounds.

    Fix: Flapper or fill valve.

    Toilet Repair →

  • Irrigation leak or schedule

    Most common

    Tell: Meter moves when the irrigation valve is open; soggy zone.

    Fix: Repair the zone; reset the controller.

  • Leaking service line

    Possible

    Tell: Meter moves with the house shutoff closed.

    Fix: Line repair or replacement.

    Water Line Repair →

  • Slab or in-wall leak

    Possible

    Tell: Meter moves with all fixtures off; toilets pass.

    Fix: Leak detection.

    Leak Detection →

Asking the utility for an adjustment

Many utilities offer a one-time leak adjustment once you show the leak was repaired, typically with a plumber's invoice or receipts for parts. Policies differ, so ask before paying a disputed bill, and keep photos of the leak and the meter readings before and after the repair.

Why not to ignore it

The same leak that raises the bill can be damaging the house. A slab or in-wall leak wets framing and flooring for weeks before it shows, and a leaking service line can undermine a walkway or driveway. Finding the cause is usually cheaper than another month of the bill.

When to call a plumber

  • The meter shows a leak you can't find.
  • The leak is on the street side of your shutoff, in the service line.
  • You need a written repair record for a utility adjustment.

More questions

How much water does a leaking toilet waste?

A slow flapper leak can waste dozens of gallons a day; a fill valve running into the overflow can waste hundreds.

Can a water meter be wrong?

It's possible but uncommon, and meters that fail usually under-read. Rule out leaks first, then ask the utility to test the meter.

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