Private Water Supplies in Wales: information to support public heath Louise Ander and Gareth Farr

There are about 15,000 recorded private water supplies in Wales, supplying approximately 77,000 people (DWI, 2017).  Whilst many people, especially in rural areas, use private water supplies and not ‘mains’ water, they can pose risks to health and well-being if they are not properly managed and monitored. These risks can be from poor chemical or microbiological quality, as well as vulnerability to insufficiency of supply.

Water quality can be directly affected by factors which include: the local environment, the chemistry of the local rocks; any corrosion of lead-containing pipes or solder; how the water source is protected from surface sources of contamination; and, maintenance of treatment systems used in properties. The year round availability of water to users can be influenced by one or more of the following factors: water consumption; weather patterns, such as drought; local geology; and, implementation of properly designed infrastructure including localised water storage.  

In Wales about 90 % of the public water supply is from surface water (e.g. reservoirs) and as a result there is a paucity of groundwater information in Wales. This lack of groundwater information becomes apparent when we consider that the majority of private water supplies, unlike public supplies, abstract from groundwater (springs, wells and boreholes) and explains why geology is so important to both quality and quantity of these supplies.

An example of integrating existing stream sediment Pb data (left) with private water supply testing failures (right). Private Water supply data (Drinking Water Inspectorate), Stream sediment data reproduced with the permission of the British Geological Survey ©NERC. Ordnance Survey Maps © Crown Copyright and database rights 2018

A recent NERC innovation project (NE/N01751X/1), focused on knowledge exchange and data-sharing to better understand risks to private water supplies.  NERC innovation aims to foster partnerships between scientists and government bodies to address challenges and opportunities that can both benefit societal wellbeing and the environment.

During this two-year project, Louise and Gareth visited representatives of each of the 22 Local Authorities across Wales and spoke to the environmental health officers responsible for private water supplies, as part of the knowledge exchange activities.  Meetings with local authorities, as well as key national organisations such as Public Health Wales, involved the discussion of common issues and concerns and where useful existing BGS/NERC data was highlighted. This knowledge exchange was successful, ‘opening up’ these data for Local Authority officers, being integrated into the Water Health Partnership for Wales website and highlighted in the Environmental Public Health Service in Wales Annual Review.

Louise and Gareth will continue to work on private water supplies in Wales, by representing BGS on the ‘Water Health Partnership for Wales’ and liaising with Welsh Government, Public Health Wales Natural Resources Wales and Local Authority officers across Wales. We would like to say a huge thank you to all of these partners.  A future blog will update on the aspects of the project which have focused on gaining new knowledge through data sharing !

Each of the 22 local authorities in Wales visited during the project. Ordnance Survey Maps © Crown Copyright and database rights 2018. All photographs by Gareth Farr & Louise Ander (BGS).