Rainwater harvesting is encouraged by the Code for Sustainable Homes and, since April 2010, Part G of the Building Regulations has also begun to address water efficiency. Both the Code and Part G apply universally regardless of whether homes are being built in watery Kendal with its 1500mm annual rainfall or arid Chelmsford with its mere 625mm. Is that logical?Whilst we may all agree that it makes sense to save water, is rainwater harvesting really the best way to do it?
Some thoughts:
• Chelmsford and the parts of the UK where much of the new development is taking pace are already ‘water-stressed’ and so rainwater harvesting should make sense. But the trouble is that there’s not enough rain falling throughout the year in these places to make harvesting viable.
• A report recently published by the Environment Agency (supported by the NHBC Foundation and the Energy Saving Trust) concludes that rainwater harvesting systems add to homes’ energy use and CO2 emissions.
• The carbon emitted during manufacture and installation, added to the ongoing energy used by the systems’ pumps, means that these systems consume more energy and emit more CO2 than the mains water supply. Clearly there is an opportunity for manufacturers to optimise their systems.
Is rainwater harvesting really the right way to tackle water efficiency? Should consumers want this technology if its benefits are questionable? Wouldn’t a roll-out of water metering (already standard for new homes) be a more effective solution?
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