Facts and figures

Water companies have recently submitted their draft 2019 Water Resources Management Plans. The data presented here is based on analysis of the final 2014 plans, and will be updated as more information from the new plans becomes available.

We have extracted information from the water resources management plans (WRMPs) published by water companies in 2015 in order to provide a national picture. We hope the resulting summary maps of the present situation and projections to 2040 will give a new perspective.

The images are available for you to download and use, as long as BGS is suitably acknowledged: see our terms of use. We have also produced some summary facts and figures in Table 1.

Groundwater volumes in public supply

The volumes of groundwater used for public supply in the countries that make up the UK are given in the table below. Ml/d = millions of litres per day. Ml/a = millions of litres per annum (year).

Country Volume per day (Ml/d) Volume per year (Ml/a) Source of data
England 6064 2 213 360 Water resource management plans, 2015
Scotland 235 85 775 Ó Dochartaigh et al., 2015
Wales 40 14 600 Water resource management plans, 2015
(Dŵr Cymru Welsh Water)
Northern Ireland 3.7 1357 Calculated from information in Northern Ireland Water, 2013

We have calculated the volume of groundwater in public supply in England by summing all groundwater source deployable output (DO) values for each water company in England, using data from the 2015 water resource management plans (WRMPs).

Groundwater used to provide about 10 per cent of public water supply in Northern Ireland (NIEA, 2009), but those sources have mostly been decommissioned. In 2013, Northern Ireland Water reported that just 0.6 per cent of the more than 620 million litres of water supplied daily came from groundwater sources (Northern Ireland Water, 2013).

Images for download

These figures are described elsewhere within these pages. You are welcome to use these figures as long as the BGS is suitably credited: see our re-use policy.

Groundwater as a percentage of deployable output, 2015
Groundwater deployable output, Ml/d 2015
New groundwater resources schemes planned by 2040

Sustainability reductions by 2040
Climate change impacts by 2040
Combined sustainability reductions and climate change impacts by 2040

Terms of use: Open Government Licence

You may freely use and re-use these images under the terms of the Open Government Licence (OGL), subject to the following conditions:

  1. The acknowledgement: "Contains British Geological Survey materials ©NERC [year]" must accompany the materials
  2. Where the materials have been adapted, the BGS logo must be removed from the figures and it must be clearly stated that the figures have been adapted.


This is a very brief glossary, which we hope will help readers understand these pages. Extensive glossaries are provided by water companies as part of their WRMPs, e.g. South East Water glossary.

Deployable output (DO)

Deployable output (DO) is a measure that water companies have to calculate for each of their water sources. The DO for a source is the amount of water the source can supply, under worst historic drought conditions, and bearing in mind constraints such as: abstraction licence, pumping plant, water quality, losses due to treatment. The DO is in effect the amount of water that a source can provide given natural and legislative/regulatory constraints, measured after the treatment stage.

Groundwater as a percentage of deployable output

We have calculated the "groundwater as a percentage of DO" for each water company by comparing the sum of all groundwater source DOs to the sum of all of the company's source DOs, using data from the 2015 WRMPs.

Water resource management plan (WRMP)

Water companies review their water resource management plan (WRMP) every five years. During this process they look ahead and identify pressures on the future public water supply, for example, the size of population and how much water we are likely to need. They then estimate the size of the impact that these various pressures will have and consider what action they need to take to ensure security of supply for the next 25 years. The options appraisal process involves identifying possible options and then choosing the most viable given the various (e.g. economic, political) constraints.


Please contact Matthew Ascott for further information.