Water Leak Cost Calculator
Quantifies the water wasted and money lost from household leaks like dripping faucets and running toilets. Ideal for convincing homeowners to prioritize repairs or benchmarking against utility bills.
About this calculator
The formula models a slow drip at a fixed flow rate and calculates accumulated waste over time. For a dripping faucet (≈0.5 gallons per minute assumed in the base formula): Total cost = (0.5 gal/min × 1,440 min/day × days leaking ÷ 1,000) × (waterRate + sewerRate). Dividing by 1,000 converts gallons to the standard billing unit of 1,000 gallons. The sewer rate is added because most utilities charge sewer fees based on metered water consumption, effectively doubling the cost of waste. Running toilets leak at much higher rates (up to 200 gal/hour) and the leak-type selector scales the flow rate accordingly. Even a modest drip can waste thousands of gallons and cost hundreds of dollars annually.
How to use
Assume a dripping faucet has been running for 30 days, your water rate is $5.00/1,000 gal, and your sewer rate is $4.00/1,000 gal. Cost = (0.5 × 1,440 × 30 ÷ 1,000) × (5.00 + 4.00) = (21,600 ÷ 1,000) × 9.00 = 21.6 × 9.00 = $194.40. That single dripping faucet wasted 21,600 gallons and cost nearly $200 in one month. Select your leak type, enter the number of days and your local rates to see your actual cost.
Frequently asked questions
How much water does a dripping faucet waste per month?
A faucet dripping once per second wastes about 2,700 gallons per month — roughly the amount an average person drinks in three years. At a drip rate of 0.5 gallons per minute (a steady drip), waste climbs to over 21,000 gallons per month. The EPA estimates that household leaks collectively waste nearly 1 trillion gallons of water annually in the United States. Even one dripping faucet can add $100–$200 to your water bill each month depending on local rates.
Why does my water bill include sewer charges for water I never put down the drain?
Most municipalities calculate sewer fees based on metered water intake under the assumption that nearly all incoming water eventually returns to the sewer system. This means every gallon you waste to a leak is billed twice — once as water supply and once as sewage. Some utilities offer irrigation meters or sewer-cap programs for outdoor water use that doesn't enter the drain. Checking with your utility about such programs can reduce the effective cost of outdoor leaks.
When is it worth fixing a small leak versus calling a plumber?
A dripping faucet can often be fixed with a $5 washer in under 30 minutes, making the repair cost-effective almost immediately. Running toilets typically require a flapper replacement ($10–$20) and can save hundreds of dollars per month. If a leak involves pipe corrosion, hidden wall damage, or pressure issues, a licensed plumber is warranted to prevent structural damage that far exceeds water bill savings. As a rule of thumb, any leak that has been running more than two weeks should be repaired regardless of apparent flow rate.