- The lead times for water resources projects are quite long (they can be about 25 years) so estimates of the future demand for water must be made for at least this time ahead.
- Prediction of the future demand for water starts by looking at how demand has varied in the past. It involves breaking down the total demand into domestic, industrial and agricultural components, and identifying the economic, social, population and climate change factors which are likely to affect them in the future. Past predictions have not been accurate, especially in the long term.
- Most domestic consumers have little direct incentive to economise on water use, as only 24% of homes in England and Wales have water meters (2003). The water supply to industry is metered, so in that sector there is a financial inducement to economise on water use. 22% (2002/3) of the water put into the distribution system in England and Wales is lost by leakage, but it is very expensive, time consuming and disruptive to remedy.
- The UK as a whole has more water than it needs, but much of it is in the wrong place. Scotland, Northern Ireland and Wales have sufficient water resources, although part of the water in Wales is diverted for use in England. England has areas of both water surplus and water shortage. Groundwater is a large proportion of the public water supply in the southern and eastern parts of England. It forms only a small proportion in other parts of England and in Wales, Scotland and Northern Ireland, as the rocks in these areas are mainly older sedimentary, igneous or metamorphic rocks, and so are not good aquifers.
- The EA outlined a strategy in 2001 for water resources up to 2025. This involves resource development, demand management and environmental improvement. Resource development would concentrate on increasing winter storage, by enlarging existing reservoirs, increased conjunctive use, a possible new reservoir in the Thames catchment, inter-regional transfers, utilisation of rising groundwater in London and Birmingham and greater re-use of sewage effluent.
- The area of the UK likely to have the greatest problems with water supply in the future is the south and east of England.