In short: a faucet dripping about once per second (60 drips a minute) wastes roughly 5.7 gallons a day — about 174 gallons a month, or 2,083 gallons a year. At a typical rate of $6.00 per 1,000 gallons that's only pennies a day, but it adds up to around $12.50 a year for the water alone — and roughly double that once a matching sewer charge is included. Enter your own drip rate and rates above for your figure.
This is a planning estimate from a steady drip rate and the rates you enter. Your bill is the true measure of what a leak costs — use it to confirm the fix worked.
How the estimate is calculated
Individual drops of water are small and fairly consistent in size, so counting them over a minute is enough to estimate a flow rate. This calculator uses the commonly cited estimate that it takes about 15,140 drips to make one U.S. gallon:
gallons/day = drips/min × 1,440 ÷ 15,140
1,440 is the number of minutes in a day. Monthly and yearly totals scale that daily figure by 30.44 days and 365 days. The dollar cost multiplies the gallons by your water rate (and sewer rate, if you add one):
cost = gallons × ($/gallon water + $/gallon sewer)
Worked example. A faucet dripping 60 times a minute wastes 60 × 1,440 ÷ 15,140 ≈ 5.71 gallons a day — about 173.7 gallons a month, or 2,083 gallons a year. At $6.00 per 1,000 gallons ($0.006/gallon), that's 5.71 × 0.006 ≈ $0.034 a day, or about $12.50 a year. Turn on the sewer charge at the same rate and the yearly total roughly doubles to about $25.
Drip rate to cost, at a glance
Gallons scale directly with drip rate. Dollar figures below use a reference rate of $6.00 per 1,000 gallons for water only — enter your own rate above for an exact number, since utility rates commonly range from about $2 to $15 per 1,000 gallons.
| Drips / min | Gal / day | Gal / month | Gal / year | Cost / year |
|---|---|---|---|---|
| 15 (slow) | 1.43 | 43.4 | 521 | $3.12 |
| 30 | 2.85 | 86.9 | 1,042 | $6.25 |
| 60 (~1/sec) | 5.71 | 173.7 | 2,083 | $12.50 |
| 90 | 8.56 | 260.6 | 3,124 | $18.75 |
| 120 (fast) | 11.41 | 347.4 | 4,166 | $25.00 |
Why the numbers add up faster than you'd think
A single drip looks trivial, but a leak runs continuously — 1,440 minutes a day, every day, whether anyone notices it or not. That relentless uptime is what separates a drip from an occasional splash: even a slow leak logs more running time in a week than a dishwasher logs in a year.
The rate also tends to move in one direction. A worn washer or O-ring degrades further with use, so a slow drip today is often a faster one in a few months. Checking a leak's rate periodically — or fixing it outright — keeps the estimate from becoming an underestimate.
If the fixture drips hot water, there's also an energy cost on top of the water and sewer charges, since the water heater keeps reheating the tank to replace what's lost. That's not included above; for a hot-water leak, treat the water-cost figure here as the floor, not the full picture.
Fixing it is usually cheap and fast
Most faucet drips come from a worn washer, O-ring, or valve cartridge — parts that typically cost a few dollars and take under half an hour to replace with the water shut off at the supply valve under the sink. Compression faucets (the kind with separate hot and cold handles) usually just need a new washer; single-handle cartridge faucets need a matching replacement cartridge for the model.
If you're not sure where the leak is coming from, or the faucet keeps dripping after a part swap, the valve seat itself may be worn or mineral-scaled — more likely in hard-water areas — and may need resurfacing or a plumber's visit. Either way, compare the repair cost against what you found above: for most drips, the payback is measured in months, not years.
Curious what other leaks around the house are costing you? See the running toilet cost calculator and the general-purpose water leak cost calculator.
Frequently asked questions
How much water does a dripping faucet actually waste?
A faucet dripping about once per second (60 drips a minute) wastes roughly 5.7 gallons a day, about 174 gallons a month, or around 2,083 gallons a year. Faster drips waste proportionally more — enter your own drip rate above for a figure specific to your leak.
How many drips are in a gallon of water?
This calculator uses the commonly cited USGS estimate of about 15,140 drips per U.S. gallon. Actual drop size varies with faucet and washer wear, so this is a planning estimate rather than an exact measurement.
Does a dripping faucet raise my sewer bill too?
Often yes. Many utilities bill sewer service as a charge per gallon of metered water, on the assumption that most of what comes in goes back out through the drain. Turn on Add sewer charge above and enter your sewer rate to include it in the total.
What if it's a steady trickle instead of separate drips?
Switch to the Time a measurement method: catch the water in a measuring cup for 10–30 seconds, then enter the volume collected and the time. That gives a direct flow rate without relying on the drips-per-gallon estimate, and works for anything from a slow drip to a thin stream.
Is it worth fixing a dripping faucet?
Almost always. A drip is usually a worn washer, O-ring, or valve seat — a low-cost part and a few minutes with a wrench in most cases — against a bill that keeps compounding every day the leak runs. Fix-the-leak costs are typically recovered within one to two billing cycles.
Why does my estimate differ from my actual water bill increase?
This tool isolates one leak using a steady drip rate and your entered rate. Your bill reflects total metered use, tiered rate blocks, other leaks, and any change in the drip rate over time (drips often speed up as washers wear further), so treat this as a planning estimate and use your bill to confirm the fix worked.
Sources & references
- U.S. Geological Survey (USGS). Water Science School — drip calculator / how many drips make a gallon.
- U.S. Environmental Protection Agency (EPA). WaterSense — Fix a Leak Week facts.
- American Water Works Association (AWWA). Residential rate structure guidance.
Sarah Bennett, MS
Water Quality & Sustainability Specialist · Portland, Oregon
Environmental scientist (MS, Water Resources) with 9+ years in residential water quality, treatment, and usage efficiency, and 150+ completed assessments. Sarah writes and reviews the treatment, usage, and cost calculators on watercalculator.us. Read full bio
MS Environmental Science, Water Resources (2018) · BS Environmental Engineering (2016)