How much water your own fixtures use
Measure your own rather than looking them up. A bucket and a timer gives a shower flow rate in under a minute, a washing machine states its cycle consumption on its rating plate or in its manual, and a toilet cistern has its capacity stamped inside it. Those three cover most of a household, and every one of them is your own number rather than an average of somebody else's.
Last reviewed 14 August 2026
The short answer
Four fixtures account for most of a household, and each has a way of being measured that costs nothing.
| Fixture | Method | What you get |
|---|---|---|
| Shower | Run into a bucket for 15 seconds, measure, multiply by four. | Litres per minute. Multiply by a typical shower length. |
| Bath | Note the volume when filling, or measure the depth and the bath's footprint. | Litres per bath. |
| Washing machine or dishwasher | The rating plate or the manual, for the programme you actually run. | Litres per cycle, from the manufacturer. |
| Toilet | Read the indelible line marked inside the cistern, which states its intended flush volume. | Litres per flush, from the cistern itself. Two figures on a dual flush. |
None of that needs equipment beyond a bucket, and all of it produces a number for your household rather than for a national average that may be nothing like yours. The toilet does not even need the bucket: it is required to tell you itself.
How this works in practice
The point of measuring fixtures is subtraction. A metered total is use plus loss, so anything you can attribute to use narrows what is left for a leak.
The toilet is the exception to the whole method, and in the reader's favour. Every flushing cistern in the UK is required to be marked internally with an indelible line showing its intended flush volume together with an indication of that volume, so it is the one fixture that states its own figure rather than needing to be measured or looked up. The same rules cap a single flush at 6 litres, and a dual flush's lesser flush at two-thirds of its larger one, which is 4 litres where the larger flush is at the cap.
Three separate instruments do that rather than one UK-wide rule, and they are not even the same kind of instrument. Regulations for England and Wales, separate regulations for Northern Ireland, and byelaws made by Scottish Water under Scottish water legislation. The wording is substantively the same in all three, but writing "the regulations" about Scotland would be wrong. And in every case it is a maximum on the fitting installed rather than a description of the housing stock: it applies from the date that cistern went in, nothing is retrofitted, and a pre-cap cistern may be replaced by one delivering a similar volume. So an older cistern delivering more is entirely lawful and the cap does not describe it. Read the line inside your own.
- Measure the fixtures above, once, and write the figures down.
- Count the events in a typical week: showers, baths, machine cycles, flushes. Count for a real week rather than estimating, because the estimate is always low.
- Multiply and add for a weekly total, then multiply by 52 and divide by 1,000 for cubic metres a year.
- Compare that against the volume on your bill. What is left is unexplained, and unexplained is where a leak lives.
Expect the two to disagree even with no leak at all, because nobody counts a week accurately and because taps, cleaning, cooking and the garden are all real use that this method misses. A gap of ten or twenty per cent is ordinary. A gap of half is not.
For a quicker version of the same comparison against a national average rather than your own fixtures, expected household use per person per day takes occupancy instead of measurements.
What changes the answer
Four things, and the first is the reason the total usually comes out low.
- Undercounting events. People underestimate flushes and shower length substantially, and the error is always in the same direction. Count a real week.
- The fixtures nobody measures. Taps for washing up, hand washing, cleaning, cooking, filling a kettle. Individually small, collectively not.
- Seasonal use. A garden in July is a large and entirely legitimate addition that a week counted in February will miss completely.
- Whether the shower is mixer or electric, and at what setting. Flow varies a long way between them and between settings, which is why measuring beats looking up.
All four make measured use look lower than real use, so the unexplained remainder looks larger than it is. That is the opposite direction from the biases on the national figure, and it is worth knowing before treating a gap as a leak.
Assumptions and sources
Water resources 2024 to 2025: analysis of the water industry's annual water resources performance
Environment Agency · primary source
- Household per capita consumption: 136.5 l/person/day
- Household per capita consumption, prior year: 137 l/person/day
- Household per capita consumption, dry-year adjusted: 140.3 l/person/day
- National leakage: 2617 Ml/day
- National leakage as share of water put into supply: 19 %
PR24 common performance commitments: per capita consumption (PCC), version 2.1
Ofwat · primary-standard source
- PCC formula: (measured household consumption + unmeasured household consumption) / total household population l/person/day
Litres in a cubic metre
Exact by definition
SI definition. The litre is defined as one cubic decimetre, so one cubic metre is exactly 1,000 litres.
Days used for an annual figure
Editorial convention
Annual figures on this site are a daily rate multiplied by 365. Leap years are not modelled, so a leap year is understated by one day, which is 0.27 per cent.
No fixture volumes are quoted on this page because none has been sourced. Figures for a bath, a shower or a washing machine circulate widely and are almost never published with a method, and this site does not repeat an uncited number just because it is familiar.
The methods described here need no citation, because each one is a measurement you take yourself rather than a claim about the world. A bucket and a timer measure a flow rate. A rating plate is a manufacturer specification for the machine in front of you.
If a sourced set of UK fixture volumes turns up, it belongs on this page as a comparison against your own measurements rather than as a replacement for them. Your own fixtures are what your own bill is made of.
What to do next
Three things, and the first takes ten minutes once.
- Measure the four fixtures above and write the figures down. They do not change, so it is a one-off.
- Count events for one real week rather than estimating, and accept that the count will still be low.
- Compare the total against your billed volume, and treat a remainder of more than a quarter as worth measuring at the meter rather than as proof of anything.
The meter settles what the arithmetic cannot. take two readings over a measured interval measures the whole property with nothing running, which no amount of fixture counting can do.
Common questions
- Why does this page not have a table of typical figures?
- Because none has been sourced. Figures for a bath, a shower or a washing machine are quoted widely and almost always without a method, and repeating an uncited round number is exactly what this site was built not to do. Your own fixtures are measurable in about ten minutes, and the result is yours rather than an average.
- How do I measure a shower?
- Run it into a bucket for 15 seconds at the setting you normally use, measure what came out in litres, and multiply by four for litres per minute. Multiply that by the length of a typical shower and you have the figure for your household rather than for a shower somebody else has.
- What about the washing machine?
- The rating plate or the manual states water consumption per cycle, usually in litres, and it is a manufacturer figure for that model rather than an average. It varies by programme, so use the one you actually run.
- And the toilet?
- Lift the lid and read it. Across the UK, every flushing cistern is required to carry an indelible line marked inside it showing the intended volume of flush, together with an indication of that volume. So the toilet is the one fixture where you neither have to measure nor take anybody's average: the cistern states what it was built to deliver. On a dual flush there are two figures.
- Is there not a legal maximum?
- There is, and it is 6 litres for a single flush. But it caps the device installed rather than describing what is in most homes, it only applies from the date the fitting went in, and nothing is retrofitted, so an older cistern delivering more is perfectly lawful. That is exactly why the marking matters more than the maximum: the line inside your cistern is your number, and the cap is only a ceiling on new ones.
- Is this worth doing?
- It is if a bill has surprised you. Adding up measured fixtures and comparing the total against a billed volume is the only way to see whether the gap is behaviour or a leak, and it is the difference between a suspicion and a number.