Corporate Responsibility

Security of supply.

Last reviewed:
Water is essential for everything we do, so it’s vital we’re able to balance supply and demand. We're responsible for ensuring we have sufficient water to meet our customers' demands, and we measure this through the security of supply index (SoSI) with our regulator, Ofwat.

How SoSI works.

The weather determines how much water is available for our customers, but it’s becoming increasingly unpredictable. During periods of hot and prolonged dry weather, the amount of water available to us can decrease, affecting our ability to meet our customers’ future needs.

SoSI is used to assess the extent to which we’re able to guarantee our planned levels of service. We compare the amount of water available during a dry year with typical customer demand, network leakage and customer side leakage to assess if we have enough water. SoSI also lets us assess water resources, leakage and demand management issues, and track changes in the service we’re offering our customers.

If we achieve lower scores on the SoSI index, restrictions on water use may be needed more often. The acceptable frequency of water restrictions depends on the agreed levels of service we plan for but we’re continuing to work hard to avoid more restrictions than our customers view as acceptable.

How are we doing?

With the pressures of population growth and climate change, it’s becoming more difficult to balance supply and demand for water each year.

Our leakage performance during 2017/18 had an impact on our SoSI performance and we finished the year 2 points down on 2016/17’s performance of 99. This reduction in score is caused by the projected shortfall between supply and demand in London, but many of our other areas, stretching from Guildford to Banbury and Cirencester, are still in surplus.

Our look forward.

Every five years we produce a Water Resources Management Plan (WRMP) setting out how we’ll maintain a sustainable balance between water supplies and demand over the next 25 years, as a minimum. It’s critically important for us to plan for the long term, because the decisions and investments we make now will determine the level of service that we can provide to our customers into the future. In February 2018 we published our draft plan, called the draft Water Resources Management Plan 2019, which sets out how we plan to provide a secure and sustainable supply of water for our customers over the next 80 years, from 2020 to 2100.

We ran a public consultation from 9 February to 29 April 2018 to get feedback on our draft plan. We published a report on 3 October 2018 setting out the comments we received and explaining how we’ve taken these into account, as well as new information, in revising our draft plan. We are holding a further consultation on the changes made to our draft plan for eight weeks, from 3 October to 28 November 2018. The report on the consultation and the revised draft plan has been sent to the Secretary of State for the Environment, Food and Rural Affairs (Defra), to everyone who participated in the consultation and published on our website here.