Calculating Water Use
Usually you’ll find a single cistern feeding 2-4 urinals. You can get a ‘back of the envelope’ figure for water use and potential savings quite simply.
1. Measure the Cistern
Measure the cistern in centimetres. Try to account for the thickness of the construction material and that the water won’t go all the way to the top – it’s the internal dimensions we need. then multiply H x W x D so a cistern that’s 30cm high x 4ocm across x 19cm deep = 22,800. Divide that by 1,000 to get the value in litres – 22.8 litres. Let’s round that up to 23.
2. How Often Does It Flush?
There’s no shortcut to this one. You need to time the interval between flushes. Let’s say it’s 18 minutes. One day is 24hrs x 60mins = 1,440 minutes per day. So, 1,440 divided by 18 = 80 flushes per day.
80 flushes per day x 23 litres = 1,840 litres. Per year that’s a staggering 671,600 litres. Which is 671.6 tons. Or 671.6m3.
Check the water / sewerage charges for your area. Each provider has a slightly different rate but it’s generally around the £2 / m3 mark. Multiply that out and that’s £1,343.20 per year. Four urinals: £335.80 each.
3. What Can I Save?
Obviously we’d need to do a proper survey but our waterless urinal system is about £1 per urinal per week. So that’s a cash saving of £1,135.20 plus nearly 700 tons of one of Nature’s most precious resources.
Where’s the Catch?
There isn’t one. No capital cost, no plumbing changes – just a simple urinal cake full of friendly bacteria that are slowly released into the urinal drain plus the biological cleaning fluid that goes with it – bacteria are alive and so bleach or harsh cleaning chemicals will kill them and you’ll need to start again. Just spray on and leave.
What Else Do I Need to Know?
Just that the friendly bacteria in the urinal cakes and spray are brilliant at removing the source of odours; use them for all toilet cleaning and you’ll get rid of all the whiffs without the need for expensive, ozone-depleting aerosols.
