Rainwater Harvesting – the next big environmental thing?

Many of us have a Water Butt to help water our flowers and vegetables throughout the dryer times of the year. They are convenient, save money and provide ‘soft’ water that is better for plants to absorb. Nothing new here – been doing it for years.

Now there is a more substantial solution, ideal for new build properties and can simply be retrofitted to existing properties. Harvested Rainwater can only be used for a few uses: Flushing the loo, washing your clothes could reduce consumption of potable (drinking) water that we pay for (and if you are on a meter – your sewerage charge is based on the amount of clean water that you consume).

An efficient washing machine consumes about 50 litres of water (there are models still being sold that use up to 200litres. A washer-dryer or condenser dryer uses cold water to help dry the clothes – typically about 35 litres. If all that water could be collected from your rainwater downpipes – that would be good.

A modern toilet cistern can use between 200 and 400 litres of water per day, it depends on how new the design is, and how many times it is used of course. Again, potable water is not essential for this purpose, rainwater would do fine.

Watering the garden whether a hosepipe ban is imposed or not is a nice luxury, and it could save your vegetable garden. Other uses for the hosepipe could include washing the car(s), windows and the like.

A larger tank is required, and preferably a hybrid system so that if the tank runs dry it could revert to mains water until the next cloud break occurs. Most systems incorporate a pump so that water pressure is as good as or stronger than mains water pressure.

Tanks can be located above ground or underground. The benefit of the underground is that the temperature remains quite stable, and water retains clarity better. An above-ground solution takes up some space and might suffer temperature changes and the potential for Algae or Bacteria to occur.

From a cost-saving viewpoint, my calculations indicate a breakeven time of 20 years or so, it depends on how much you can save on installation costs and the volume of water used in a household. There are other reasons to consider such an investment:

• The probability of drought is increasing due to climate change.
• Water companies use significant amounts of energy refining drinking water – this will become more expensive.
• Reducing water consumption by harvesting something provided for free is always attractive.
• Reducing your carbon footprint by storing in times of plenty improves matters for others.

I am certain that in future, just as Solar panels will be required on all new housing developments, fossil fuel connections will no longer be made, Rainwater Storage is simple to instal at the construction stage. The development curve has already been paid by early adopters, the components are now mainstream (forgive the pun) and most of the components that make up a pack are manufactured in the UK.

Few people are doing much more than a garden water butt, some have made videos on how to adapt things to work, there are now companies that do this and comply with all the legislation that needs to be observed.