During Water Saving Week 2026 we asked a water expert – why the UK can’t just store winter rain for summer?
After one of the wettest starts to the year in many parts of the UK, households and businesses may be wondering: if it’s raining this much, why are we still being encouraged to save water? And why can’t we just save it to use when we need it?
According to water experts, the answer isn’t as simple as “just store it and use it later”. Oli Shelley, Director of Water Efficiency Services at national water retailer, Wave, explains why Britain’s rainy reputation doesn’t automatically protect us from summer shortages.
“People understandably are looking outside at the continuous rain and thinking, ‘Surely we’ve got plenty,’” says Shelley. “But rainfall and usable water aren’t the same thing. The UK doesn’t actually have a rainfall problem overall. What we have is a storage, treatment and distribution challenge. The rain doesn’t always fall where demand is highest, we don’t have unlimited capacity to capture and hold it, and it must still be treated and made safe to drink before reaching our taps.”
While western parts of the UK receive high levels of rainfall, the South East – where millions of people live – is much drier. Much of the drinking water in these areas doesn’t come from reservoirs at all, but from underground.
“In places like London and the South East, a large share of our water comes from groundwater,” explains Shelley. “That’s rainwater that has slowly filtered down through soil and rock and is stored beneath our feet. In this part of the country, the rock is mainly chalk, which acts like a natural sponge. It looks solid, but it’s full of tiny cracks and spaces that hold water.”
For those underground stores to refill properly, they need steady winter rainfall.
“When rain falls slowly over weeks and months, it has time to soak in and recharge those underground supplies,” says Shelley. “But when we get short, heavy downpours, much of that water runs straight into rivers and out to sea instead of soaking into the ground. That means a very wet week doesn’t automatically translate into secure summer supplies.”
Many of the UK’s major reservoirs were constructed in the mid-20th century, with very few large-scale projects added in recent decades.
“Building new reservoirs takes years of planning, significant investment and careful environmental assessment,” says Shelley. “It’s not something that can be done quickly in response to one dry summer.”
Experts say the issue is less about how much rain falls annually and more about how it falls. “We’re seeing wetter winters but also hotter, drier summers,” says Shelley. “When rain comes in short, intense bursts, more of it runs straight into rivers and out to sea before it can be stored.”
According to Shelly, small behavioural changes still make a difference, especially in water-stressed regions. “Simple steps like fixing leaks, taking shorter showers and using water-efficient appliances help protect supplies in peak summer demand. Water resilience isn’t just about infrastructure, although that’s it increasingly important, it’s about using what we have wisely.”
