How Much Does a Dripping Faucet Cost per Year?

A faucet that drips once per second wastes roughly 2,000 to 3,000 gallons of water a year, which costs about $10 to $45 at combined water and sewer rates of $5 to $15 per 1,000 gallons. EPA puts a one-drip-per-second leak at more than 3,000 gallons a year; the smaller drop size used by USGS works out to about 2,100. The exact bill depends on how fast the faucet drips, how big the drops are and what your utility charges per gallon — and if the drip is hot, you're also paying to heat water that goes straight down the drain. Here's how to work out your own number.

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How much water a dripping faucet wastes

A single drop is almost nothing. The problem is that a drip never stops: at one drop per second, a faucet leaks 86,400 times a day, every day, until someone fixes it. The table below turns common drip rates into gallons.

Why two columns? There is no scientific standard for the size of a faucet drip. USGS measured kitchen and bathroom sink faucets and found drips of roughly one-fifth to one-third of a milliliter, with bathtub drips nearer half a milliliter, and it uses ¼ mL, which equals about 15,140 drips per gallon. EPA's published figures — more than 3,000 gallons a year for one drip per second, and more than 500 for a showerhead dripping 10 times a minute — imply somewhat larger drops, about 0.36 mL by our arithmetic. Treat the range as your realistic window.

What it costs at different water rates

Cost is gallons multiplied by your rate. Because rates differ widely between utilities, the table uses three illustrative combined water-and-sewer prices per 1,000 gallons. Find your actual rate on a recent bill.

If your drops are on the larger side, scale up by roughly 44%. A one-per-second drip at EPA's 3,000 gallons a year costs about $15, $30 or $45 at the same three rates.

Two billing details matter. Some utilities charge in hundreds of cubic feet (CCF) rather than gallons; one CCF is about 748 gallons. And many utilities use tiered pricing, so a leak is billed at the highest tier you reach that month, not the average. If you need to convert your bill into a per-gallon rate, the water cost per gallon calculator does it in a few seconds.

Work out your own faucet

You can estimate your own cost in two steps. First, count drips for one minute and convert to gallons per year:

Second, multiply by your rate:

Counting works for a slow drip but gets unreliable when drops run together. For a faster or uneven leak, catch it instead. Hold a measuring cup under the faucet for 10 minutes and note the milliliters:

The catch method removes the drop-size guesswork entirely, which is why it's the better measurement when the number matters. The dripping faucet cost calculator handles the arithmetic and lets you enter your own rate.

Costs the water rate leaves out

Sewer charges. Many utilities bill sewer service in proportion to the water you use indoors, so a gallon that drips into the sink is billed once as water and again as sewer. If the rate you used above covers water only, add the sewer rate before you trust the result.

Water heating. A drip from the hot side also wastes the energy used to heat it. Raising a gallon of water by 60 °F takes about 500 Btu, or roughly 0.15 kWh. Over 3,000 gallons that comes to about 440 kWh a year with an electric resistance heater, or roughly $70 at an illustrative $0.16 per kWh. A gas heater or a smaller temperature rise lowers it. To run your own numbers, use the energy to heat water calculator.

Real-world examples

Four common situations, using USGS's ¼ mL drop and an illustrative $10 per 1,000 gallons:

Why faucets drip

A faucet stops water with a seal, and a drip means that seal no longer closes fully. In older compression faucets the culprit is usually a worn rubber washer or a pitted valve seat. In single-handle faucets it is more often a worn O-ring or cartridge. Ceramic-disk faucets can drip when mineral scale keeps the disks from meeting flush, which is common in hard-water areas. Higher supply pressure pushes more water through a marginal seal, so the same worn part can drip faster than it would in a low-pressure home.

The fix is typically a small replacement part rather than a new faucet, which is why a drip is one of the cheaper leaks to repair.

Is it worth fixing?

Often, but be realistic. A slow cold-water drip may cost only a few dollars a year, which won't dominate a repair decision. The case gets stronger when the drip is fast, when it's hot, when your rates are high, or when it keeps getting worse. Replacement parts are inexpensive next to several years of waste, so a do-it-yourself repair usually pays back within a year or two, while a plumber's visit stretches that out. A drip also doesn't improve with age, since the worn part keeps wearing.

If you suspect a leak but can't find a dripping faucet, test the whole house. Turn off every fixture and appliance, then check whether your water meter's low-flow indicator is still moving. EPA also notes that a family of four using more than 12,000 gallons a month in winter likely has a serious leak somewhere.

Bigger leaks to check first

A dripping faucet is usually not the biggest leak in the house. EPA says the average home's leaks can waste more than 9,300 gallons a year, several times what one faucet loses. USGS notes that a constantly leaking toilet loses about 22 gallons a day, or roughly 8,000 gallons a year. If you're hunting for waste, check the toilets first, then the faucets and showerheads. The running toilet cost calculator and the water leak cost calculator price those leaks the same way.

The bottom line

A faucet dripping once per second wastes about 2,000 to 3,000 gallons a year and costs roughly $10 to $45 in water and sewer charges, with a hot-water drip adding energy cost on top. A slower drip costs much less, a faster one much more. To pin down your own number, measure the drip, multiply by your rate, and compare it with the price of a replacement washer or cartridge. When you'd rather skip the arithmetic, the calculator below does it for you.