For the whole of the East of England water supply is an increasing problem. Here in Cambridge we need to reduce the amount we take from our aquifers by about half in order to protect the chalk streams. This will be achieved with a combination of reducing leakage, reducing demand and increasing supply (by building large reservoirs). One way to reduce demand is to harvest rainwater for use where it does not have to be drinking quality, such as flushing toilets.
Eddington in North West Cambridge has a rainwater harvesting system for 3000 homes, the largest in the country. It is often cited as an exemplar for water saving, with every home having two supplies: one from rainwater (non-potable) for use in the garden, in the washing machine and flushing the loo alongside the one from the mains for everything else. As I recall, the pipework has different colours. The rainwater is stored in a rather beautiful lake and is fairly clean but not as clean as the water we get from the chalk aquifer; there is equipment for basic treatment on site. The problem is, the rainwater harvesting supply has never been commissioned due to concerns from the Drinking Water Inspectorate (DWI).
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjCL8a6qVYRz9H8b_1m-U8f0ZGj_kYEEYa2UBLM2QgLyrsBUbjVStqZy0unNYoOrXWOZ51CPWP1NgwBjPvfeD7OJc_gUpMrn4gkQOfT4vLAmYxvStVtXp2qI87iXv5g7OAsLxExFTgjaYXEMUtpLfUVv5LGyt8B2pOev9b4GgLJ2jNAicTAGIHPx863GDAB/w400-h210/eddington-lake.jpg) |
Brook Leys Lake at Eddington – stores rainwater for supply to homes, but not commissioned for use. |