Call a Plumber Soon Avg. cost: $350
Unexplained Water Bill Spike: Causes, Fixes & When to Call a Plumber
A high water bill without obvious leaks is most commonly caused by a running toilet (200–400 gallons/day), an outdoor irrigation leak, or a slab leak. Check your water meter: if the leak indicator spins with all fixtures off, you have an active leak. Call a plumber for leak detection.
What Causes Unexplained Water Bill Spike?
- Running toilet (most common — up to 400 gallons/day)
- Dripping faucets across multiple fixtures
- Underground irrigation system leak
- Slab leak (pipe running under the concrete foundation)
- Failing water softener regenerating constantly
- Meter error (rare)
How to Fix High Water Bill: Step-by-Step
- 1Read your meter, turn off all water, wait 20 minutes, read again — any change confirms an active leak
- 2Check each toilet with dye tablets or food coloring in the tank
- 3Inspect all faucets and under-sink connections
- 4Check outdoor hose bibs and irrigation systems
- 5Look for water stains on ceilings, walls, or floors
When Should You Call a Plumber?
Call a plumber if you've checked all obvious fixtures and the meter still shows active flow. A plumber can use acoustic leak detection to find hidden leaks without unnecessary digging.
How Much Does High Water Bill Repair Cost?
Average Cost $350
Typical Range $150 – $3,000
Costs vary by location, severity, and whether emergency service is needed. Prices shown are national averages. Get a free quote from a local plumber →
Frequently Asked Questions About High Water Bill
- Turn off all water in the house. Find your water meter (at the curb or outside). Look for the leak indicator — a small triangle or dial. If it moves with everything off, you have an active leak. The meter shows flow even from a single running toilet.
- A slab leak is a pipe leak under your concrete foundation. Signs include: wet or warm spots on the floor, water sounds when no fixtures are running, a hot spot on the floor (hot water slab leak), or unexplained water bill increase. They require professional leak detection and repair.
- Many utilities offer a one-time leak adjustment credit when a confirmed hidden leak is repaired. Submit your plumber's invoice along with your before/after meter readings to request an adjustment.