Drip Leak Water Waste Calculator
Find out how much water a dripping faucet wastes per year and what it costs you. Use this whenever you spot a slow leak to make the case for a quick repair.
Last updated: September 2026
Formula below · 2 sources (epa.gov, Wikipedia) · Updated Sep 2026
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About this calculator
A dripping tap wastes far more water than it appears to. The annual cost formula is: Annual Cost = dripsPerMinute × dropSize × 525,600 × waterCost ÷ 1,000,000. Here, 525,600 is the number of minutes in a year (365 × 24 × 60) and drop size is in millilitres (the USGS drip calculator assumes 0.25 mL per drip, the Small setting). Drips per minute × mL per drip × 525,600 gives mL per year; dividing by 1,000,000 converts mL to cubic metres, and multiplying by your water cost in $/m³ gives the annual cost. A slow drip of 10 drips/min at 0.25 mL wastes about 1,314 litres (1.3 m³, about 347 U.S. gallons) per year.
How to use
Say your faucet drips 30 times per minute, each drop is about 0.5 mL (Medium), and your water costs $1.50/m³. Annual waste = 30 × 0.5 × 525,600 = 7,884,000 mL = 7.884 m³ (7,884 litres). Annual cost = 30 × 0.5 × 525,600 × 1.50 ÷ 1,000,000 = $11.83. The direct cost seems small, but that one leak wastes nearly 8,000 litres of treated drinking water a year. If sewer is billed on metered water too, enter your combined water + sewer rate to see the full cost.
Frequently asked questions
How much water does a dripping faucet waste per year?
A faucet dripping at just 10 drips per minute — barely noticeable — wastes approximately 1,314 litres (about 350 gallons) per year at the USGS assumption of 0.25 mL per drop. At 60 drips per minute (one per second), waste climbs to about 7,900 litres (2,100 gallons) a year; the EPA's often-quoted figure for a one-drip-per-second leak is about 3,000 gallons a year, which corresponds to slightly larger drops. Across an average home with multiple fixtures, unrepaired leaks can account for 5–10% of total household water consumption, according to water utility estimates.
How do I measure how many drips per minute my faucet is leaking?
Place a measuring cup under the drip for exactly one minute and count the drops, or measure the collected volume. Alternatively, time how long it takes to fill a known volume — for example, if 100 mL collects in 2 minutes, you can back-calculate drip rate using your drop size. A typical drip is roughly 0.25 mL (the USGS assumption), so 100 mL in 2 minutes is 50 mL/min, or about 200 drops/min — which would indicate more of a trickle than a drip.
Is it worth fixing a slowly dripping faucet to save money?
The direct water-cost savings from a single slow drip are often under $5 per year, so purely financial ROI can be modest. However, the environmental argument is stronger — hundreds of litres of treated, pressurised drinking water are wasted for no benefit. Additionally, persistent drips can erode washers, damage sink basins, and eventually worsen into more costly leaks. A simple washer replacement typically costs under $5 in parts and prevents compounding damage.