Check out our infographic to see our water resource situation at the end of May:
In May, we experienced below average rainfall in the Thames Catchment. At 23mm, it was 42% of the long-term average.
The graph below shows how rainfall differs from the long-term average for the Thames catchment:
Soils remained drier. Soil moisture deficit (SMD) was above average for the time of year across the Thames region by the end of May 2025.
Groundwater levels were mostly average across the Thames region at the end of May 2025. View our latest groundwater levels.
In May 2025, river flows in the River Thames and River Lee remained below average for the time of year. The Teddington Target Flow (TTF) remained at 800 Ml/d at the end of May.
At the end of May 2025:
You can learn more about the status of water resources in the Thames region and beyond from regular Environment Agency reports.
It’s easy to assume water will always be there when we need it. But increased demand and our changing climate mean it’s more important than ever that we work together to save water where we can.
There are lots of ways you can do this, from turning the taps off when you’re brushing your teeth to using rainwater for your plants. Saving water helps protect the environment, including rare chalk streams – particularly during hot and dry weather when rivers, streams and the wildlife they support can be vulnerable.
Learn what we’re doing to protect this precious resource and how you can save water at home with our top water-saving tips.
From morning showers to brushing our teeth at night, water plays an essential part in our day-to-day lives.
The clean water that comes out of our taps is taken from rivers and natural underground stores. The dirty water that leaves through our sewers is treated before we safely return it to the environment. This is all part of the water cycle – and rainfall is a vital part of it.
It may feel like it rains a lot in the UK, but did you know that our capital city gets less rain each year than Rome, Istanbul and even sunny Sydney?
River flows reflect groundwater levels and rainfall. Rain flows off the land and into the rivers, while groundwater can well up from below. Much of the water we supply comes from rivers in our region, including the Thames, Lee, Kennet, Wey and Tillingbourne.
When using these rivers, we need to make sure we balance environmental and necessary navigational needs with the needs of our water supply. We do this through agreements with the Environment Agency.
In London, the Teddington Target Flow is particularly important. This is the minimum River Thames flow over the Teddington weir required to balance these needs. Controls like this vary depending on the time of year and the amount of water stored in our reservoirs. They’re always agreed with the Environment Agency.
We store water, pumped from the River Thames and River Lee, in large reservoirs in Oxfordshire, West London and North London. In North London, we top up the reservoirs with groundwater pumped from the chalk aquifer.
The raw water in our reservoirs and rivers is clean enough to support a variety of wildlife, but not safe enough to drink. Before it reaches your taps, we pump the raw water to our world-class treatment sites for cleaning.
We carefully monitor water levels in our reservoirs and regularly inspect and maintain them to safeguard your supply.
Our reservoirs are home to a diverse range of wildlife, and many are open for the public to enjoy. Learn about visiting our reservoirs and nature reserves.