Carbon emissions have grabbed the headlines for many years when it comes to sustainability, but water is just as important, if not more. Human settlement can only take place where there is a water supply, after all. Fortunately, we are a well-watered isle. But in parts of the country – especially the Southeast, where rainfall
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Carbon emissions have grabbed the headlines for many years when it comes to sustainability, but water is just as important, if not more. Human settlement can only take place where there is a water supply, after all. Fortunately, we are a well-watered isle. But in parts of the country – especially the Southeast, where rainfall is lowest – there is pressure on water supply, which may in turn limit development.
Unfortunately, the Southeast has also experienced the largest population growth in recent times, and it’s expected to continue. Perhaps the obvious solution is to concentrate new house building in the Northwest and other areas where land is much cheaper, employment is needed and building costs are lower.
The other factor in this equation, which is completely outside of the control of developers, is the water supply companies. While population has grown, storage capacity and the distribution system in general has not kept pace. Public utilities have failed us. It’s convenient to blame climate change but, if you look at the hard numbers, almost no new storage capacity has been added to the network over the last 35 years. During that period, the UK population has risen by over 20% and, as has been widely noted, water companies have been in private ownership. Leakage in the supply system, initially reduced after privatisation, also continues to be a major issue, running at around 20% according to Ofwat.
How much water do we use?
Over the years, housing density has increased – so people have smaller gardens (if at all) and thus there has been a reduction in demand for outside water use. Perhaps more importantly, WC flush volumes have decreased. As 20-30% of domestic water use is for WC flushing, a reduction from the old 9L to newer dual 4-6L delivers a really significant saving – with existing WCs being gradually replaced and water efficient versions installed in all new builds. There is also the fact that appliances such as washing machines and dishwashers have also become more water-efficient, driven in part by a desire to save energy.
However, against that we have to recognise that there is increased demand for water in some areas of domestic consumption – we shower and bathe more regularly than we used to, for instance, and we wash our clothes and bedding more frequently. It’s often claimed that having a shower rather than a bath saves water, but I’m not convinced – for one thing it depends on how long you spend in the shower. Four minutes is optimal but rare.
Where is water used around the home?
This table shows an average water consumption, broken down into the different uses.
| Source | Percentage |
|---|---|
| Shower | 25% |
| Toilet | 22% |
| Cold taps | 22% |
| Hot taps | 11% |
| Washing machine | 9% |
| Bath | 8% |
| dishwasher | 1% |
| Garden | 1% |
| Car | 1% |
Is household water demand falling?
Demand per capita has fallen slightly from the oft-quoted 150 litres per person per day (lpd) to just below 140 lpd. A 5-10% decline over 30 years is normally accepted as a fair summary of what has taken place.
It’s hard to pin this down, but much of the saving can be attributed to the adoption of efficient WCs. The other important factor is the widespread introduction of water metering. This means that your bill is directly linked to your water use, and you are more likely to be careful if you know it’s costing you money.
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