My largest, which is a box-like galvanised tank, holds around 500 gallons. Added to the other butts and tanks dotted about, I reckon we have a rainwater reserve of about 900 gallons. I'm not quite sure why this is considered virtuous by environmentalists. Presumably if I didn't save it the water would soak into the ground and recharge the underlying aquifer, and then if I wanted to use it I'd have to pay for it, so I might not bother, and so reduce consumption. As it is, what I don't use gradually evaporates anyway.
The evangelists mislead us into believing that reducing water use is somehow automatically morally virtuous, as if water were a fossil fuel or a polluting agent. But, contrary to what they tell us, water is a renewable resource, and it is not as scarce as we are led to believe. Enough water falls in the UK, even in individual regions, to supply any conceivable domestic needs. We simply don't store enough of it. Watch any river after heavy rain; every minute millions of gallons of fresh water go tearing past on their way to the sea. That's where the real waste of water occurs, dwarfing the effect of bricks in our cisterns, bathing with a friend, avoiding flushing and all the other sticking plasters that are rolled out whenever we have a drought.
The government is encouraging people to buy water butts. A 200 litre butt costs about £35. If each of the 25 million households in the UK bought one, it would cost about £875 million. That's equivalent to one and a half million Oxfam well-digging kits. It is also equivalent to the cost of constructing, say, about eight new reservoirs (if you count a reservoir as £100 million, which is what they say one near here would cost).
There is also a drive to limit water consumption by metering. Meters are installed in new houses, and the first water companies have adopted an all-metering strategy. Even ten years ago it was estimated that it would cost around £4 billion to install meters in the country's 21 million unmetered homes. That's equivalent to another 44 new reservoirs. In addition, a metered system of water charging would cost £500 million a year more to administrate. That's five new reservoirs every year.
Water companies are also coming under relentless pressure to cut leakage (even though in many cases leaking water is probably returning to recharge aquifers). There is a diminishing return on investment in leakage reduction. Thames Water alone is spending £500 million on it in a five year period. That's equivalent to five new reservoirs serving London.
I can't begin to estimate the cost of installing state-of-the-art domestic water conservation measures - grey water recycling, etc. Nor the cost and waste of global resources of prematurely replacing existing domestic fittings, cisterns, etc. with lower-consumption equivalents.
You get my point. We are spending and planning to spend far, far more on reducing our use of water than we would need to spend simply providing more. As population and household numbers grow and global warming bites, the demand for water will increase. Metering and other usage reduction measures can slow the rate of demand growth, but sooner or later we'll need to build more reservoirs anyway. So why not spend the money on doing that now? Then there won't be this short-term need to turn water into a scarce resource, and to invest billions in infrastructure which doesn't stop a single pint of useful rainwater from falling into the sea.
Funny things anyway, reservoirs. We object like mad to new ones, but once they exist they become treasured features of the landscape, wildlife assets and valued leisure facilities. Just try telling people you are going to get rid of an established local reservoir, and wait for the uproar. And we're not short of agricultural land, which is being set aside or being turned to leisure uses anyway.
There do at least seem to be a few ifs about butts.