"DIY" Water Audit Business Premises



Ref No: OWR 9720 December 1998

DIY Water Audit Business PremisesOur job at Dwr Cymru Welsh Water is to make sure you have all the water you want, when you want it, whatever the weather, whatever the time of day or year.


We were able to maintain water supplies during the 1995 drought without any restrictions, there was no need for a hosepipe ban. We intend to do the same in future years, whatever the weather. After all this is our job and it's what you pay us to do.


At the same time, we know you would want us to make sure that we don't take anymore water from the environment than we need to. We are firmly committed to water conservation and promoting water efficiency. We continue to make good, sustainable progress on leakage reduction and at the same time provide our customers with advice and, where possible, practical assistance to use water wisely.


Our DIY Business Premises Water Audit leaflet illustrates how you can use water more wisely.


If you are interested in promoting water efficiency measures within your business it starts with raising staff awareness.



Average water use

Does your premises have higher than average water use?


The average use per person in a typical office (or office type factory unit) is 50 litres
per person per day.


  • What is the per person per day use for your office?
  • Is it higher than normal?
  • You can work it out from your latest water bill
Water used per quarter (M3) x 1000
Number of employees x
number of days in quarter
? litres per person per day



Where it all goes

Typical pattern of office water use




Toilets and washrooms

plugOver half of the water we supply to you is flushed down the toilet or urinal.


Flushing the toilet
An older toilet cistern can use up to 13 litres per flush, whilst more modern cisterns use between 7 and 9 litres per flush. There are new low flush models available that only use 6 litres per flush.


If you have the bigger cisterns try placing a device in the cistern to reduce the volume used per flush.


Urinal flushing
Approximately 20% of the water supplied to offices is used in the flushing of urinals.


All new urinals must be fitted with a control device to ensure that the cistern only flushes after it is used, but the majority of urinals flush day and night - a significant waste of water.


There are many flushing control methods, some of which only operate when the urinals are used e.g. infra red sensors, water pressure sensors, temperature sensors; some that operate on room entry e.g. magnetic door switches, infra red door beams and the simplest which operate on a basic time controller. Whatever control system is installed it must suit your requirements.


A power shower (one with a pump to increase pressure) can use virtually the same amount of water as a bath - 80 litres of water.


An ordinary shower uses 35 litres of water and a low volume shower head can save a further 5 litres of water.


Running taps
A running tap can use up to 9 litres of water a minute.

Consider installing spray taps or self closing "push operation" taps or merely encourage staff to put the plug in the hand



The canteen

washing machineDishwashers and washing machines
A washing machine uses up to 80 litres of water per cycle whether its full or not, and a dishwasher between 22 and 35 litres per cycle.


Always use a full load or select the economy setting. When replacing consider choosing an ECO "water efficient" model.

Running taps
A running tap can use up to 9 litres of water a minute.


Use a bowl of water or put the plug in the sink when washing up or preparing vegetables.



Ground maintenance

A water sprinkler uses between 300 - 650 litres of water an hour, more than the average household uses in one day.


Too much watering encourages shallow root growth.

Use a hose with a trigger control, fit a rain water butt, mulch plants.



Washing cars / vans

A hosepipe (15mm) without a nozzle can use up to 1000 litres per hour.

Use a hose with a trigger control. If using an automatic car wash, try and choose one that recycles the water.




About three quarters of leakage happens on Dwr Cymru's pipes, and about a quarter on pipes owned by businesses and households.


Leaking supply pipes - check drives, paths and grass areas for unusual wet patches - you may have a leak on your supply pipe (the pipe that joins your premises to our water main). An easy test, if you have a water meter, is to turn off all the taps and water using appliances (including urinals) and check that the meter does not move. Alternatively, read the meter at the end of the working day, after everyone has left the building, and again in the morning before anyone starts work. If there is a difference in the readings there may be a leaking pipe - remember to switch off any automatic flushing urinals.


If you spot a leak call us on our Freephone leakline on 0800 281432 - we will be able to help you.


If you have any problem with your meter contact us on 0800 0520140.


Dripping taps - A dripping tap can waste up to 30 litres of water each day. Replace washers on both inside and outside taps as soon as you spot the first drip.


Overflows - check all overflows to ensure they are not running unnecessarily.


Stop cock location - make sure you know where the stop cock is, so that you can turn the water supply to your premises off quickly in the event of an emergency.


Frost protection - make sure that all pipework and water tanks, both inside and outside of the building are adequately lagged. Leakage levels increase significantly following freezing weather.


If you would like advice on frost protection please ring our Freephone lagline 0800 281 432 for our advice leaflet "Don't crack up Wrap up".