Short answer
A hidden leak shows up as a higher water bill, a meter that moves when all water is off, stains or bubbling paint, warm spots on a slab floor, musty smells or the sound of running water. The meter test is the fastest way to confirm one.
The meter test
- Turn off every faucet, appliance and irrigation
- Find the meter in the box near the street
- Watch the small leak indicator (triangle or dial) for 5–10 minutes
- If it moves, water is flowing somewhere
Rule out the toilet
Put a few drops of food coloring in the tank and wait 15 minutes without flushing. Color in the bowl means a flapper leak, the most common 'hidden' leak.
How plumbers find it
- Isolating sections with valves
- Acoustic listening devices
- Thermal imaging for hot-water lines
- Moisture meters on walls and floors
Room-by-room leak check
- Kitchen: look under the sink for damp cabinet floors; check behind the fridge ice-maker line and dishwasher
- Bathrooms: dye-test toilets, check around tub spouts and shower valves for soft drywall
- Laundry: inspect washer hoses for bulges; replace rubber hoses with braided ones
- Water heater: look for moisture in the pan and rust at fittings
- Crawl space: look for wet soil, dripping pipes or mold on joists
- Yard: walk the line from meter to house for soggy spots
What a leak costs if you wait
A small drip may only add a few dollars a month to a water bill, but water inside a wall or under a floor damages framing, subfloor and drywall and invites mold. Finding and fixing a leak early is almost always cheaper than repairing what it damages. If your water bill is high and you can't find the source, professional leak detection pinpoints it without guesswork.
When to call a plumber
If the steps above don't solve it, or anything involves sewage, gas, electricity near water or a leak you can't stop, call a licensed plumber. Related help: leak detection in Gastonia, pipe repair in Gastonia, water line repair in Gastonia.
Where this comes up most in Gaston County: Willow Creek, York-Chester, Loray Mill Village, Downtown Gastonia, Forest Heights, Highland, Belmont, NC, Mount Holly, NC. See all Gastonia and Gaston County service areas.
Frequently asked questions
Can a hidden leak damage my foundation?
A long-running leak under a slab or near footings can saturate soil and cause damage. Find and fix it early.
Editorial note: this guide gives general safety and maintenance information for homeowners. It doesn't replace an on-site diagnosis by a licensed plumber. Codes and permit rules can change; check with your local inspections office.