Quick Answer
A sudden spike in your water bill can come from increased household use, irrigation, a running toilet, an appliance or fixture leak, a hidden supply leak, or sometimes a billing or rate change. A careful meter test is a useful next step after confirming that all intentional water use is off.
Common Symptoms
- •Water bill jumped with no change in usage
- •Meter spinning when nothing is on
- •Sound of running water with nothing turned on
- •Warm spot on the floor
- •Lush or wet patch in the yard
Possible Causes
- •Running toilet (the most common silent waster)
- •Slab leak under the foundation
- •Pinhole leak in copper piping
- •Underground water service line leak
- •Failing supply line behind a wall
Safe Things You Can Check
Confirm all intentional and automatic water use is off before watching the meter, including irrigation, appliances, treatment equipment, and toilets.
Check toilets: add food coloring to each tank, wait about 15 minutes without flushing, and see whether color appears in the bowl.
If you know the location of a building-side shutoff and can operate it safely, compare meter behavior before and after closing it to help isolate whether unexplained flow is upstream or downstream of that valve.
Also compare the bill period with irrigation, guests, seasonal use, and any utility rate or billing changes before assuming a hidden leak.
WHEN TO CALL
If unexplained metered flow remains after the simple checks or you see active moisture without a clear source, we can isolate the plumbing and use appropriate leak-detection methods to narrow the likely source before recommending access or repair.