Netley Mills water treatment site outage affects up to 9,000 properties

Thames Water notified Surrey County Council's Emergency Management and Resilience Team that ongoing issues had put its Netley Mills water treatment site out of service in August 2022, according to the council's record of past incidents in the county¹. Up to 9,000 properties were affected at a time when the Met Office was issuing Amber warnings for extreme heat in the UK¹.

The council's account sets out the welfare response. A welfare cell led by Surrey County Council's Adult Social Care team was established, and bottled water was delivered by the Surrey 4x4 Team to vulnerable customers who were being affected¹. Thames Water set up a bottled water station to help others affected while services were restored¹. The council's record does not give the cause of the outage, the dates within August 2022 on which it began or ended, or how long supplies were interrupted.

The same council record lists other water incidents in Surrey for comparison. In November 2024, Thames Water told the council that 665 properties were experiencing water supply interruption due to multiple burst mains in the Tatsfield area, which subsequently affected levels at the Betsoms Hill reservoir; a bottled water station was set up locally and a local school and child care facilities were supported¹. In May 2018, around 1,800 addresses in Merstham were affected by a water outage lasting over 24 hours, with teams from partner agencies distributing water to vulnerable people¹. In July 2015, a major incident was declared in Runnymede and Spelthorne when a water shortage occurred during a heatwave following a burst water pipe in Egham¹.

Source: Surrey County Council, Past incidents in Surrey¹

Why it matters for households

The Netley Mills outage shows how a treatment works failure can interrupt supplies to thousands of properties at once, and that the response included deliveries to vulnerable customers and a bottled water station for others¹. The council's record does not state which areas or postcodes were affected, so the streets covered have not been reported. Households can check whether a supply problem is known in their area using the guide on how to check if there is an outage in your area, and the supply interruption checklist sets out what to have ready. For households classed as vulnerable, the guide on how to get bottled water delivered if you are vulnerable explains how water companies handle deliveries, and bottled supplies, tankers and bowsers from your water company covers the other emergency supplies companies provide. The council's account records that a bottled water station was established¹; the guide on where bottled water stations are set up describes how these are run. The wider water hub covers treatment, storage and flushing the toilet during an outage.

What happens next

No reopening date for the site, compensation arrangements or follow-up report have been reported in the material available.