The short answer: A suddenly high water bill is almost always a leak, and the top suspect is a silently running toilet, which can waste 200 gallons a day. Run the meter test: turn off every fixture, then watch your water meter for 15 minutes. If it moves, water is leaving somewhere, and the checklist below finds where.
Nobody memorizes their water bill until the month it doubles. When that happens, the money is going somewhere physical: through a flapper that does not seal, a drip that never stops, an irrigation zone that runs at 3 a.m., or, in the case this region knows too well, a pipe under the slab. Work this list in order; most people find their answer by step three.
Step 1: The meter test (10 minutes, settles everything)
- Turn off every faucet, appliance, and ice maker. Make sure nobody flushes.
- Find your meter (usually in a ground box near the street) and look at the low-flow indicator: a small triangle, star, or gear on the dial.
- Watch for one full minute. Any movement with everything off means a leak.
- Now close the main shutoff at the house and look again. Still moving? The leak is between the meter and the house: the buried service line. Stopped? The leak is inside.
That one split (outside vs inside) is half the diagnosis, and you just did it for free.
Step 2: Interrogate the toilets (the guilty party 8 times out of 10)
A flapper that seals imperfectly lets water trickle from tank to bowl around the clock: silent, invisible, and worth 100-200+ gallons a day, which at Lafayette-area rates can add serious money to a monthly bill. The test costs nothing: drop food coloring (or a dye tablet) into the tank, wait 20 minutes without flushing, and look in the bowl. Color in the bowl = failed flapper. Also listen at night for the phantom refill: a toilet that hisses or cycles briefly every so often is topping off what the flapper leaks. Flappers harden and warp with age (and our chlorinated water is not gentle with them); a few dollars in parts ends it. Run the dye test on every toilet; the guest bathroom offender is a classic. Travis shows the whole toilet-tank leak check in under a minute in this video.
Step 3: The visible-drip audit
- Faucets and showerheads: one drip per second is roughly 3,000 gallons a year.
- Water heater: check the pan and the relief valve line for discharge (our leaking guide covers what each spot means).
- Outdoor spigots and hoses: a hose left cracked open behind the shrubs is a bill-doubler.
- Irrigation: run each zone manually and look for geysers, then check the controller for a schedule someone set in 2023 and forgot. A broken zone valve can run water underground where you never see it.
- Water softener/filtration: a stuck regeneration cycle recirculates water endlessly.
Step 4: The slab leak question (the Louisiana chapter)
Nearly every home in Lafayette, Youngsville, and the surrounding towns sits on a concrete slab with water lines running through or under it. Our clay soils swell and shrink dramatically as moisture changes (drought summer, then a tropical deluge), and that movement works on pipes year after year until one gives. Signs the leak is under your slab:
- A warm patch on the floor (hot-line leaks announce themselves this way)
- The sound of running water with everything off
- Hairline cracks appearing in flooring or drywall, doors newly sticking
- Damp carpet edges or baseboards with no ceiling stain above
- Meter test says “inside” but no fixture confesses
- A water heater that runs constantly (hot-side slab leak drains it invisibly)
Slab leaks are exactly why professional leak detection equipment exists: acoustic listening, line tracing, and thermal imaging find the leak through the concrete, so repair means opening one square foot in the right place instead of trenching hopefully. If your checklist ends here, stop guessing and book the detection visit; the equipment pays for itself in concrete not broken.
When the bill is high but nothing is leaking
Before you accept defeat, rule out the boring answers: a rate increase (check the per-gallon line, not just the total), estimated-vs-actual meter readings catching up, house guests and their showers, a new appliance, or summer lawn watering. If usage (gallons, not dollars) genuinely jumped and the checklist found nothing, the meter itself can be tested, and a leak between meter and house can be surprisingly quiet; soggy ground or a green stripe in the lawn along the service line’s path is its only signature.
Frequently asked questions
How much water does a running toilet waste?
A bad flapper typically wastes 100-200 gallons a day; a stuck-open flapper can exceed a thousand. It is the single most expensive “small” plumbing problem in any house.
Will the water company adjust my bill for a leak?
Many Louisiana utilities offer a one-time leak adjustment with proof of repair. Keep your repair invoice; we itemize ours so it works for exactly this.
How do professionals find a leak without digging?
Acoustic microphones hear pressurized water escaping, tracer equipment maps the line, and thermal cameras see temperature differences through slab and drywall. We locate first, then open only where the leak actually is.
Is a slab leak covered by insurance?
Commonly the resulting damage and the access (breaking/repairing the slab) have coverage while the pipe repair itself does not; policies vary. Documentation from a licensed plumber is what the adjuster wants either way.
Bill jumped and the checklist points to a leak?
Hargrave’s finds leaks without wrecking your house to do it: meter-to-fixture diagnosis, electronic slab leak location, and firm quotes before repair, across Lafayette, Youngsville, and all of Acadiana. Book online or call 337-344-3920.
