How much does a leaky faucet cost?

Measure instead of guessing

Collect the drip volume for a timed interval, or count drops for a minute and repeat. A slow leak can vary with pressure and temperature, so take more than one sample.

Use the rates on your bill

Multiply daily gallons by the number of days in the billing period, then apply the water rate and any sewer charge that is based on volume. A hot-water leak can also carry an energy cost.

Repair the cause, not only the symptom

A worn washer or cartridge is common, but the correct part depends on the faucet. Shut off the local supply before disassembly, protect the drain, and call a plumber for a seized valve, concealed leak, or water near electrical equipment.

Useful signal: if the faucet is dry but the water meter moves with every fixture off, use the whole-home meter test instead of assuming the faucet is responsible.