Dripping tap water loss calculator
How much water and money a dripping tap wastes per day, month and year.
Fill in the fields and the result will appear here automatically.
A single drop seems like nothing, and that is the trap: ten drops a minute is nearly three hundred litres a year, and a steady drip once a second carries off more than a cubic metre. The meter counts cubic metres rather than drops, which is why that row sits next to the money. The drop volume is entered separately: it depends on the tap and on whether the water is still dripping or already running.
How it works
Formula and logic
At an average D drips/min and entered drop volume v mL, daily loss L=D×1440×v/1000 litres. The displayed month is 30 days and year 365 days:30 L and 365 L. Annual cubic metres=365 L/1000; annual cost is that amount times the tariff per m³. D may be a fractional average rate; the calculator does not measure the drop.
Example
Ten drips a minute is 0.72 litres a day and nearly 263 litres a year. At 60 drips/min and 0.05 mL:4.32 L/day and 1576.8 L over 365 days.
Fields and units
- Drips per minute — drops/min
- Water price per m³ — $
- Drop volume, ml — mL
How to use
- — Count the drips over fifteen seconds and multiply by four — easier than timing a whole minute.
- — The retained 0.05 mL is an example. Measure your average drop volume; there is no universal value.
- — If the tap runs as a thin continuous stream, counting drips is pointless — that is already litres per hour.
- — Take the per-m³ tariff from your bill, including only applicable variable components.
Method and limitations
- Calculation method
- Formula and logic
- Data or methodology source
- USGS: no universal drip size; its 0.25 mL example differs from our 0.05 mL input
- Limitation
- The retained 0.05 mL is an example. Measure your average drop volume; there is no universal value.
FAQ
Is a drip a second really a lot?
At entered 0.05 mL, one drip per second is 60 per minute,4.32 L/day and 1576.8 L over 365 days. Larger measured drops increase loss proportionally. This is arithmetic for the selected drop, not a measurement of your tap.
Why is the drop volume an input rather than a constant?
A drip has no universal volume: USGS states this and uses 0.25 mL in its example. The editable 0.05 mL assumption is retained here. Changing 0.03 to 0.08 mL scales the answer by 8/3≈2.67; measurement beats a general “typical” value.
Does this include waste water charges?
Only if the entered tariff includes it. Add the applicable variable water and sewer rates without repeating fixed charges. Rate ratios and billing rules depend on your bill; doubling the cost is not universal.
When is it worth fixing?
The calculation gives water loss, not parts or repair prices. Compare actual costs and the fault; no claim that every washer is cheaper than a cubic metre follows. For a stream, measure volume over time instead of counting drips.