I am also a Three Valleys customer, and in the past I worked in the water industry on the government side.

If you look at detailed local rainfall data for last winter, you will observe that the Chilterns was not as starved of rainfall as most other SE areas - 75% rather than the 50% in parts of Surrey/Sussex/Kent. It is demonstrably true that less water gets into aquifers during the growing season, though rainfall will certainly add a short-term boost to watercourses that are mainly spring-fed, and to surface water sources (a third of TVW's supply). There is currently no flow in the Misbourne river at all. The last time there was no flow in the Misbourne, we had a three-year hosepipe ban (approx 1988-1991).

I am prepared to believe you that TVW does not really need a hosepipe ban at the moment. A hosepipe ban only reduces water consumption by 2%, which makes little difference ("every little helps", lied some government spokesman, embarrassed by the low number). What hosepipe bans can usefully do is preserve water pressure, which can be seriously compromised when everyone in the road is sprinklering their lawn in the evening of a hot summer's day, and we don't need that yet. Serious water savings come from a drought order. The Enviroment Agency is encouraging Thames Water, TVW, and others, to apply for drought orders. They are resisting: a drought order will reduce consumption by major commercial customers, who are metered, and therefore hit the companies where it hurts, in the bank account.

In Britain, water supply shortages are a result of inadequate water supply infrastructure, obviously we have plenty of water if we have the infrastructure to store and harvest it, as even a "drought" in Britain is much wetter than many places. A water company has several choices how to increase water supply: water transfer schemes (the fabled water grid), improved leakage control, construct new storage reservoirs, develop new resources, and (for coastal companies) desalination. All of these are costly, but often the cheapest is leakage control, and long distance water transfer the most expensive. Water companies agree an asset management plan with OFWAT, the price regulator, which then funds the companies asset plans by setting water charges at a level to cover the costs. In short, if a company plans to spend money on leakage control, and OFWAT agrees to it, we the customers have to pay for it. So the much derided "economic leakage plan" is actually a careful balance between customers' bills and security of supply. I believe OFWAT has in the past erred on the side of low bills, but it has recently been persuaded to allow more expenditure on leakage control in the SE.

For comparison, average levels of leakage are Spain 40%, UK 29%, France 27%, Germany 9%, Netherlands 5%. But this 29% conceals wide variations - levels of leakage have been reduced in areas with supply shortages, so that they are now typically 17% in the drier parts, but higher in London where it costs a lot to dig the road up. There isn't much point doing much leakage control in soggy, sparsely populated, parts of the country, so in some wet areas leakage is around 50%. So we will never have German levels of water leakage, because it just isn't worth it in the soggy parts of Britain.

So we could have more leakage control, but you the customer would have to pay for it. Probably the Environment Agency wants drought orders to soften us up, so we won't complain when the water companies put up their prices to pay for more leakage control, and cause chaos on the roads implementing it.

Thames Water recently applied for planning permission to build a desalination plant in E London; this may indeed be an economic method of covering supply peaks, Thames Water justified it in relation to saving the chaos of digging up roads. I can't imagine they would run it most of the time. It was refused planning permission by Kuddly Krimson Ken. Modern methods of reverse osmosis desalination use much less energy than the old flash boiling method, but still a lot more than normal water supply.

New houses means additional expenditure on water supply infrastructure. No problem with this, the shortage is in infrastructure, not water, it just costs money to improve the infrastructure. (Same issue as in arid southern Spain with all their new villas and strawberry farms.) In theory that will be paid for by the new occupants of those houses, though in practice it doesn't really work like that, and existing customers will probably end up bearing some of it.