Free Tool · Updated September 30, 2026

Leak Cost Calculator: What Is That Leak Costing You?

Illustration: DryLine Home

A steady leak rarely looks expensive. It's a drip, a toilet that keeps running after you flush, a water meter that won't sit still. This calculator turns it into gallons and dollars using your own water rates, so you can decide how fast it needs fixing.

How to use it

Pick a typical leak, enter what you collected in a container, or use two water-meter readings.
Use your own rates. The defaults are examples; your bill has the real numbers.
Sewer charges often apply to water that goes down a drain, so an indoor leak usually costs more than an outdoor one.
This covers the water bill only, not damage to the house.

1. How do you know how much is leaking?

A typical leak (EPA figures) I collected water in a container I have two water-meter readings

Type of leak

Each figure comes from EPA WaterSense, converted to gallons per day. Where the EPA says "more than" or "or more," we use the stated minimum. The running-toilet figure is from a 2009 EPA release. For the outdoor sprinkler leak, untick the sewer box below, since that water usually never reaches a drain.

2. How long has it been running?

Duration

Unit

3. Your water rates (from your bill)

Water rate ($)

Sewer rate ($)

Rates are per

The leaked water goes down a drain (sewer charge applies)

Example rates only. Published municipal rate sheets vary widely; two we checked came to roughly $16 and $33 per 1,000 gallons combined.

Water lost

0 gal/day

Cost per day

at your rates

Cost per month

30.4-day month

Cost per year

Cost for the time entered

How to measure your own leak

The presets are handy for a ballpark. Your own number is better, and there are a few ways to get it.

Collect it. If you can catch the water, time it. One cup in a minute is about 90 gallons a day, far more than most people expect from something that looks like a trickle.
Read the meter. The EPA suggests checking your meter before and after a two-hour stretch when no water is being used. If the meter changes at all, you probably have a leak. Enter both readings and the hours between them above. Our guide to finding a hidden leak goes through it step by step.
Test the toilet. Put a few drops of food coloring in the tank. If any color shows up in the bowl after 10 minutes without a flush, the toilet is leaking. Flush right afterward so it doesn't stain the tank. More in our dye test guide.
Look at a cold-month bill. The EPA says a family of four using more than 12,000 gallons in a colder month such as January or February could have serious leaks.

What the EPA says typical leaks waste

3,000+gallons a yearA faucet dripping once per second
500+gallons a yearA showerhead leaking 10 drips per minute
9,300+gallons a yearLost to leaks by the average household
50+gallons a dayWasted in the leakiest 9% of homes
200+gallons a dayA toilet that runs constantly (2009 EPA release)

Household leak waste, in the EPA’s own figures. Source: EPA WaterSense, Fix a Leak Week. “+” means the EPA says “more than” or “or more.”

Leak	EPA figure	Per day (our conversion)
Faucet dripping once per second	More than 3,000 gallons a year	About 8 gallons
Showerhead leaking 10 drips per minute	More than 500 gallons a year	About 1.4 gallons
Toilet running constantly	200 gallons or more per day (2009 EPA release)	200 gallons or more
Average household, all leaks	More than 9,300 gallons a year	About 25 gallons
Leakiest 9% of homes	50 gallons or more per day	50 gallons or more
Sprinkler line with a 1/32-inch hole	About 6,300 gallons per month	About 207 gallons

Source: EPA WaterSense, Fix a Leak Week, page last updated March 13, 2026. The running-toilet figure comes from a 2009 EPA WaterSense release; the current page says a worn flapper can silently leak thousands of gallons a year. Fix a Leak Week is the third week of March (March 16 to 22 in 2026). Per-day values are the EPA's yearly figures divided by 365, or its monthly figure divided by 30.44.

How the math works

Gallons per day. Presets use the EPA figures above, converted to gallons per day. A collected sample is amount × seconds-per-day ÷ seconds timed. Meter readings are the difference in gallons (cubic feet × 7.48) ÷ hours × 24.
Cost per gallon. Your water rate, plus your sewer rate if the box is ticked, divided by 1,000 gallons (or by 748 gallons if your bill is in CCF).
Cost over time. Gallons per day × cost per gallon, scaled to a 30.44-day month, a 365-day year, or the duration you entered.

Nothing you type is sent anywhere. The calculation runs in your browser.

What this number leaves out

The water bill is often the smaller cost. A slow leak inside a wall, under a floor or behind an appliance keeps soaking whatever is around it, and by the time the bill jumps, drywall, subfloor and insulation may already be wet. The first 48 hours checklist and our piece on how fast mold grows cover that side of it.

Insurance is the other gap. Many homeowners policies respond differently to sudden damage than to a long-running leak, so read yours before assuming a slow leak is covered. Our breakdown of what insurance typically covers is a good place to start. If you'd rather catch the next leak early, see our leak detector comparison.

FAQ

Common questions

How much water does a dripping faucet waste?

A faucet dripping once per second can waste more than 3,000 gallons a year, according to the EPA. That works out to roughly 8 gallons a day. A showerhead leaking at 10 drips per minute wastes more than 500 gallons a year.

How much does a running toilet cost?

A 2009 EPA WaterSense release said a toilet that runs constantly can waste 200 gallons or more per day, and the EPA's current page says a worn flapper can silently leak thousands of gallons a year. At 200 gallons a day and the example rates in the calculator ($6.00 water plus $8.00 sewer per 1,000 gallons), that is about $2.80 a day, or roughly $85 a month. Your own rates will change that number, so enter them from your bill.

How do I measure how much my leak is losing?

Hold a container under the leak for a timed minute and enter what you collected, or take two water-meter readings with everything off and enter the hours between them. The calculator converts either one into gallons per day.

Do I pay sewer charges on leaked water?

Often yes, if the water goes down a drain, because many utilities bill sewer based on how much water you use. Outdoor leaks such as a leaking hose bib or sprinkler line usually don't reach the sewer, so untick the sewer box for those. Check your bill or ask your utility.

Does this include the cost of water damage?

No. It covers the water bill only. A steady leak inside a wall or under a floor can cost far more in damage than in water, and homeowners policies often treat long-term leaks differently from sudden ones. See our guide on whether leak detection is covered by insurance.

How do I know if I have a leak at all?

The EPA suggests reading your water meter, waiting two hours with no water in use, and reading it again. If the meter changes at all, you probably have a leak. For a toilet, put a few drops of food coloring in the tank; if any color shows up in the bowl after 10 minutes without flushing, the toilet is leaking.

Leak Cost Calculator: What Is That Leak Costing You?

How to measure your own leak

What the EPA says typical leaks waste

How the math works

What this number leaves out

Common questions

How much water does a dripping faucet waste?

How much does a running toilet cost?

How do I measure how much my leak is losing?

Do I pay sewer charges on leaked water?

Does this include the cost of water damage?

How do I know if I have a leak at all?

More on finding and stopping leaks