Sellafield has previously used water from the River Ehen for cooling on the site, but ceased this operation in the 1990s. There is a weir on Ennerdale Water, and as at 2016 the valley continues to be an important source of drinking water for customers of United Utilities in West Cumbria. However, there are plans to supply these customers using a new pipeline from Thirlmere because the Environment Agency has confirmed that for environmental reasons it will rescind the abstraction licence for Ennerdale. This means United Utilities must stop using it as a source of water by 2025 at the latest, and therefore will need to find one or more alternative sources of water.