UK water: how it works
Four nations, four regulatory systems, three ownership models and a rainfall gradient that puts the water in the north west and the people in the south east.
Water in the UK is devolved, which means there is no single UK water system. There are four, with different regulators, different ownership and different charging arrangements — and comparing them is one of the more informative natural experiments available in the sector.
| Row | England | Scotland | Wales | Northern Ireland |
|---|---|---|---|---|
| Ownership | Private regional monopolies | Publicly owned corporation | Company limited by guarantee, no shareholders | Government-owned company |
| Economic regulator | Ofwat | WICS | Ofwat | Utility Regulator |
| Quality regulator | DWI | DWQR | DWI | DWI NI |
| Environment regulator | Environment Agency | SEPA | Natural Resources Wales | NIEA |
| Household charging | Separate water bill | Collected with council tax | Separate water bill | No separate household charge |
| Number of companies | 16 water and/or sewerage companies | One | Two | One |
The rainfall problem
Scotland receives roughly twice the rainfall of England. Wales receives nearly as much. The population is concentrated in the south and east, which is the driest part.
Annual totals for different countries are not comparable as a measure of water availability. A large arid country and a small wet one can have similar national average rainfall while having entirely different renewable water resources per person. Gauge networks also differ in density, and mountain precipitation is systematically under-measured.
View the data behind this chart
| Subject | Value (mm) | Notes |
|---|---|---|
| Wales | 1,446 | — |
| Scotland | 1,391 | — |
| Northern Ireland | 1,106 | — |
| United Kingdom | 1,061 | — |
| England | 798 | — |
Parts of Essex and Cambridgeshire receive under 600 mm a year — comparable with parts of Spain, and less than Jerusalem. Combine that with the highest population density in the UK and you get the central fact of English water resources: the water is in the wrong place relative to the people.
Where UK water comes from
- England: roughly a third groundwater, mostly chalk and sandstone, with the remainder from reservoirs and river abstraction. The south east is groundwater-dominated
- Scotland: overwhelmingly upland surface water and reservoirs, generally soft and often coloured by peat
- Wales: upland reservoirs and rivers, with significant transfer to England through the Elan Valley and Lake Vyrnwy aqueducts
- Northern Ireland: Lough Neagh and upland reservoirs
Why hardness varies so much
UK water hardness maps almost exactly onto geology. The chalk and limestone of southern and eastern England produce very hard water; the granite, sandstone and peat of Scotland, Wales, Cornwall and the Pennines produce soft water. This has nothing to do with the water company and cannot be changed by them.
Sources
- Met Office — HadUK-Grid gridded climate observations. Open — attribution required · Open Government Licence v3.0
- Water Services Regulation Authority — Water company performance and price review data. Open — attribution required · Open Government Licence v3.0
- Drinking Water Inspectorate — Drinking water quality in England and Wales. Open — attribution required · Open Government Licence v3.0
- British Geological Survey — Groundwater levels, aquifer mapping and baseline chemistry. Open — attribution required · Open Government Licence v3.0