Don’t Throw Your Money Down The Gutter

As a nation we are now paying for our domestic water. This brings us in line with most other countries but has still caused enormous uproar amongst many people. However, instead of arguing about the charge why not do something to minimise it? Your gutter is overflowing with money, so do something about it!

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Image from Shutterstock.

If you could capture just some of the rainwater that falls on your roof then you could see a saving on your water charges. How much? Well let’s take a look.

Take a regular 3-bedroom semi-detached house as an example. My roof footprint (the area that will catch rain) measures 5 m × 8 m = 40 sq. m. Any rain falling on this area will flow into the gutters and flow down the drainpipe. Well, not all of it, as in some cases light rain may evaporate off the roof before it has a chance to flow into the gutter, so let’s say that 80% of the annual rain does make it down the drainpipe.

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Met Éireann's map of annual rainfall for the period 1981-2010. From their site http://www.met.ie

My nearest station, Casement Aerodrome, averages about 750 mm of rainfall per annum. This is amongst the lowest in the country. Valentia, on the other hand, averages over double that, at 1550 mm.

One millimetre of rainfall equals 1 litre per sq. metre, so my roof gets about 750 × 40 = 30,000 litres of rainfall per annum. Taking 80% of that as collectable rain means I could be getting 24,000 litres of free water every year. Someone in Valentia could be getting about 50,000 litres. Another thing to keep in mind is that the annual rainfall increases by about 100-200 mm for every 100 m rise in altitude, highest in the west, so depending on how high up you live you could add a lot more to those numbers.

The annual allowance is 30,000 litres per adult and 21,000 litres per child. Priced at €2.44 per 1000 litres we can now see that I could be saving on any usage above those thresholds by simply sticking a barrel under my drainpipes and using this water for things like flushing toilets, watering the garden, etc.

Do the maths for your location and situation and see if it makes sense for you. The water charge is here to stay, so bitching about it won’t save you money, but thinking about it in a different way might!

Met Éireann’s Climate Statistics pages
http://www.met.ie/climate-ireland/30year-averages.asp
http://www.met.ie/climate-ireland/rainfall.asp

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2 thoughts on “Don’t Throw Your Money Down The Gutter

  1. In your article don’t throw your water away. You say that we are now paying for water , this statement is incorrect and misleading , we have been paying for water through taxation for many years and would I would like you to amend this . The article is good apartment from that and I would like to see the government bring in regulation for all knew builts and government buildings to use roof water for the likes of flushing toilets instead of using Treated water.

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