Household Leak Cost Calculator

Estimate the water, sewerage and energy cost of a dripping tap, toilet leak, pipe leak or hot-water leak.

Enter Leak And Tariff Details

Leak ratelitres/hour Rate unit Days leakingdays Water unit rateGBP/m3 Sewerage rateGBP/m3 Is it hot water? Energy cost for hot waterGBP/litre Repair cost estimateGBP

Leak Cost Result

GBP 3.00

Estimated cost over the entered leak period.

Water wasted720 litres

Water and sewerage costGBP 2.88

Hot water energy costGBP 0.00

Repair paybackLonger than period

This estimate uses editable water and sewerage rates because UK bills vary by water company, meter status and tariff. A leak can also cause damage, mould risk, higher heating cost and insurance issues. If water is escaping into a wall, ceiling, floor, electrics or shared property, treat the repair as urgent rather than waiting for the cost comparison.

Why Small Leaks Still Matter

A leak that looks small can run all day and all night. One litre per hour is 24 litres per day, 720 litres in 30 days and about 8.8 cubic metres in a year. A leaking toilet can be much higher because water can pass silently into the pan. Metered homes pay for the water used, and many also pay sewerage based on water volume. A hot-water leak can add energy cost as well. The calculator separates those parts so the result can be compared with a repair estimate.

Formula Method

Litres per day = leak rate converted to litres per dayTotal litres = litres per day x days leakingCubic metres = total litres / 1000Water and sewerage cost = cubic metres x (water rate + sewerage rate)Hot water energy cost = total litres x energy cost per litre, if selectedPayback days = repair cost / daily leak cost

The water and sewerage rates should come from your own bill if possible. Standing charges are not included because they are usually paid whether or not the leak exists. If your sewerage is charged differently, set the sewerage rate to zero or enter the best equivalent rate from the bill. The hot-water field is deliberately editable because heating method, cylinder losses and temperature rise can vary. Use it only as a rough planning figure.

Leak Rate Clues

Leak Type	Possible Rate	How To Check
Slow dripping tap	Less than 1 litre per hour.	Collect in a jug for 10 minutes.
Fast dripping tap	Several litres per hour.	Scale a timed container reading.
Leaking toilet	Can be tens or hundreds of litres per day.	Use tissue test or dye test in cistern.
Overflow pipe	Depends on valve fault.	Check visible discharge outside.
Hidden pipe leak	Can be very high.	Check meter when all taps are off.
Hot water leak	Water plus heat loss.	Look for boiler or cylinder cycling.

Worked Leak Example

A toilet leak wastes 200 litres per day for 30 days. That is 6,000 litres, or 6 m3. If water costs GBP 1.80 per m3 and sewerage costs GBP 2.20 per m3, the direct bill cost is GBP 24. If the repair costs GBP 120, the water-bill payback is about 150 days at the same leak rate. That does not mean waiting is wise. A leak can worsen, waste treated water, create damp or become the homeowner’s responsibility under tenancy or insurance rules.

Meter And Bill Checks

If you have a meter, turn off taps, appliances and irrigation, then watch whether the meter still moves. Some meters have a small flow indicator. A rising night-time reading can point to a toilet, pipe or appliance leak. Compare the calculator result with your bill, but remember that a leak may not fill the whole billing period. If you rent, report leaks quickly and keep a dated note. If you own the property, check whether your water company offers leakage advice, allowances or repair guidance. Do not ignore water near electrics or structural areas.

Tenant, Landlord And Insurance Notes

Responsibility for a leak can depend on the tenancy agreement, the source of the leak and how quickly it was reported. Tenants should report leaks promptly, keep photos and avoid altering pipework without permission. Homeowners should check stop taps, isolation valves and insurance conditions before a small leak becomes a damage claim. If the leak comes from a neighbouring property or a shared pipe, write down dates, meter readings and conversations. The calculator shows water and energy cost, but the larger issue may be damp repair, escape of water damage or loss of use.

If a leak is hidden, keep before-and-after meter readings once it is repaired. They can help when discussing an unusually high bill with the water company. Keep plumber invoices too, because repair evidence may support a leakage allowance request. Add the repair date beside the meter reading.

FAQs

How do I estimate litres per hour?

Catch the leak in a measuring jug for a timed period, then scale up. For example, 250 ml in 15 minutes equals 1 litre per hour.

Does this include standing charges?

No. Standing charges are normally paid even without a leak. The calculator focuses on extra water, sewerage and hot-water energy cost.

Why include sewerage?

Many metered bills include sewerage linked to water volume. If your bill uses a different method, enter zero or adjust the rate.

Can a leaking toilet cost a lot?

Yes. A quiet toilet leak can waste far more than a visible drip. Check the pan, cistern and meter if usage rises unexpectedly.

Is hot water much more expensive?

It can be, because the leak wastes both water and heat. The energy field is editable because heating systems vary.

Should I wait if repair payback is long?

No. Payback is only a bill comparison. Leaks can cause damage, waste water and worsen quickly.

Sources

Ofwat. (n.d.). Your water bill. Ofwat. https://www.ofwat.gov.uk/households/your-water-bill/
Water UK. (n.d.). Leaks. Water UK. https://www.water.org.uk/advice-for-customers/leaks/
Consumer Council for Water. (n.d.). Water meter advice. CCW. https://www.ccw.org.uk/