How much water does a leaky faucet or running toilet waste?
Short answer: gallons per day = drips per minute × 1,440 ÷ 11,350 (the USGS drips-per-gallon estimate). A faucet dripping once a second wastes about 7.6 gallons a day, or about 2,780 gallons a year. A running toilet can waste 200 gallons or more a day, per EPA. At an example price of $10 per 1,000 gallons, that toilet costs about $60 a month.
1. Your leak
Count the drips for one minute with a watch. One drip per second is 60 drips a minute.
$10 is an example, not a national average. Prices vary widely by city. Many utilities bill sewer by water use, so add both rates from your bill. If your bill uses CCF, 1 CCF is about 748 gallons.
2. What it wastes
- Per day
- 7.6 gal
- Per month
- $2.28
- Per year
- $27.79
$0.08 a day
228 gallons in 30 days
2,779 gallons in 365 days
How this is calculated
- Faucet gallons per day = drips per minute × 1,440 minutes × faucets ÷ 11,350 drips per gallon (USGS estimate).
- Gallons per month = gallons per day × 30. Per year = gallons per day × 365.
- Cost = gallons ÷ 1,000 × your water + sewer price.
- Drip size varies. USGS assumes a drip of about 0.33 ml. EPA's figure for one drip per second (more than 3,000 gallons a year) implies a slightly larger drip, so treat results as estimates.
- A dripping hot-water tap also costs energy to heat the water. See the shower cost calculator for that math.
Dripping faucet: gallons and cost by drip rate
| Drips per minute | Gallons per day | Gallons per year | Cost per year at $10/1,000 gal |
|---|---|---|---|
| 10 | 1.3 | 463 | $4.63 |
| 30 | 3.8 | 1,389 | $13.89 |
| 60 (one per second) | 7.6 | 2,779 | $27.79 |
| 120 | 15.2 | 5,557 | $55.57 |
These use the USGS estimate of about 11,350 drips per gallon. EPA says one drip per second can waste more than 3,000 gallons a year. The two figures differ because drip size varies.
Running toilet: why it costs so much more
A faucet loses water a drop at a time. A toilet that runs nonstop sends a steady stream down the overflow tube. EPA says that can waste 200 gallons or more every day.
| Leak | Gallons per month | Cost per month | Cost per year |
|---|---|---|---|
| Silent leak, 30 gal/day (example) | 900 | $9.00 | $109.50 |
| Running toilet, 200 gal/day (EPA) | 6,000 | $60.00 | $730.00 |
Costs use an example price of $10 per 1,000 gallons and 30-day months. Use your own rate in the calculator.
How to check for leaks
- Water meter test: EPA says to read your meter, use no water for two hours, then read it again. If the reading changed, you probably have a leak.
- Toilet dye test: put a few drops of food coloring in the tank. EPA says color in the bowl after 10 minutes means a leak. Flush right away so the dye does not stain the tank.
- Winter bill check: EPA says a family of four using more than 12,000 gallons a month in January or February probably has serious leaks.
Leaks add up. EPA says the average household's leaks can waste more than 9,300 gallons a year. It also says 9 percent of homes have leaks that waste 50 gallons or more a day.
Fix it
- How to fix a running toilet
- How to winterize an outdoor faucet
- Shower cost calculator (water heating cost)
Common questions
How many drips are in a gallon?
The USGS estimates about 11,350 drips per gallon. That assumes each drip is about one-third of a milliliter.
Does a dripping hot-water faucet cost more?
Yes. You pay for the water and for the energy to heat it. The shower cost calculator shows how to estimate the heating part.
Where do I find my water price?
Check your water bill for the price per 1,000 gallons or per CCF. If sewer is billed on water use, add both rates together.
Is a running toilet worse than a dripping faucet?
Usually, yes. A faucet dripping once a second wastes about 7.6 gallons a day. EPA says a running toilet can waste 200 gallons or more.