By a licensed plumber · Plumbing Picks · Updated June 2026
Most homeowners find out about a water leak from the bill, not the puddle. By then it has been running for months. Here is what the leaks I get called for actually cost — with the national numbers behind them, and the five-minute checks that catch them before they cost you.
The headline numbers (national)
| What’s leaking | Water wasted | What it costs you a year* |
|---|---|---|
| A toilet that runs silently | ~200 gallons/day → ~73,000 gal/yr | ~$200–$700+ |
| The “average” household’s small leaks | ~9,300+ gal/yr (EPA) — about 300 loads of laundry | ~$30–$140 |
| A faucet dripping once per second | ~3,000+ gal/yr | ~$10–$45 |
* Cost range uses a combined water-and-sewer rate of roughly $0.003–$0.01 per gallon. Your local rate drives the number — see “How we calculated this” below. The U.S. average residential water bill is about $49/month, and a family of four averages ~$78; water costs rose ~7.1% year over year as of March 2025.
The numbers that make this add up
- American households waste nearly 1 trillion gallons of water a year to leaks — equal to the annual household water use of about 11 million homes. (EPA WaterSense)
- About 10% of homes have leaks that waste 90+ gallons a day. (EPA WaterSense)
- The average household’s leaks top 9,300 gallons a year. (EPA WaterSense)
- The single most common culprit I replace is a worn toilet flapper — a 5-minute, ~$10–$15 part that is quietly the most expensive thing in a lot of houses.
The plumber’s-eye part
- A “running” toilet usually isn’t loud. The expensive ones are the silent slow-bleeders — the flapper seals just enough that you never hear it.
- The leaks that actually flood houses aren’t the dramatic ones — they’re the supply line behind the toilet or under the sink that lets go while you’re at work.
- Summer is when this spikes: irrigation, more laundry, and guests turn small leaks that hid all winter into a July bill shock.
The 5-minute leak check (do this tonight)
- Read your water meter, don’t use any water for 1–2 hours, then read it again. Moved? You have a leak.
- Put a few drops of food coloring in the toilet tank. If color shows up in the bowl within ~10 minutes without flushing, the flapper is leaking.
- Check under sinks and behind the toilet for damp, mineral crust, or a musty smell.
- Look at the water heater’s base and the shutoff valves for green or white corrosion.
- Walk the basement or crawlspace ceiling for stains.
Try our free Water Leak Cost Calculator to put your own water rate and drip rate into the math, and our 2026 Plumbing Repair Cost Index and Plumbing Cost Estimator for what each fix actually runs.
How we calculated this (methodology)
Water-waste figures are EPA WaterSense published estimates. Cost ranges multiply gallons wasted by a combined water-and-sewer rate of $0.003–$0.01 per gallon: the EPA pegs water alone at roughly 3 cents per 10 gallons ($0.003/gal), and most U.S. households also pay a sewer charge calculated on water used, which commonly doubles to triples the effective per-gallon cost. We show a range because local rates vary widely by state and utility. Average-bill figures are from the Bank of America Institute (March 2025) and published utility data.
Sources
- EPA WaterSense — Fix a Leak Week (1 trillion gal/yr; 9,300 gal/household; 10% of homes 90+ gal/day; dripping faucet 3,000+ gal/yr)
- EPA WaterSense — Residential Toilets (toilet leaks up to 200 gal/day; flapper as top culprit)
- EPA WaterSense — Understanding Your Water Bill (~3¢ per 10 gallons; sewer charged on usage)
- Average bill and 7.1% year-over-year increase: Bank of America Institute, March 2025 (as reported by HomeGuide and LawnStarter).
Journalists: this data is free to cite with a link to this page. For methodology or a quote from a licensed plumber, use the contact page.
Home water-leak cost FAQ
How much water does a typical household leak waste per year?
About 9,300 gallons a year for the average household (EPA WaterSense). Nationwide, household leaks waste close to 1 trillion gallons a year, and roughly 10% of homes have leaks that waste 90+ gallons a day.
How much does a running toilet cost per year?
A toilet that runs silently wastes about 200 gallons a day — roughly 73,000 gallons a year (EPA WaterSense). At EPA’s ballpark rate of ~3¢ per 10 gallons, that’s on the order of $220 a year in water alone from a single toilet you may not even hear (sewer charges push it higher).
How much does a dripping faucet waste?
A faucet dripping about once per second wastes 3,000+ gallons a year (EPA WaterSense) — roughly $9–10 a year in water at typical rates, per drip.
Why is my water bill going up?
Two things stack: hidden leaks you’re paying for, and rising rates. The average U.S. residential water bill is about $49/month and climbed about 7.1% year over year as of March 2025 (Bank of America Institute). Fixing leaks is the part you control.
How do I check for a leak at home?
Do the 5-minute check: put a few drops of food coloring in the toilet tank and wait 10–15 minutes without flushing — color in the bowl means it’s leaking. Then read your water meter, avoid using water for an hour, and read it again; if it moved, water is escaping somewhere.