What is sustainable drainage?

When it rains, most of us don’t think twice about where the water goes.

It falls on roofs, runs down pipes, and disappears into drains.

But as rainfall becomes heavier and more unpredictable, those systems don’t always cope.

That’s where sustainable drainage comes in.

Sustainable drainage (often shortened to SuDS) is simply a different way of managing rainwater.

Instead of sending water straight into drains as quickly as possible, it focuses on managing rain where it falls.

That might mean:

In simple terms, it’s about giving rainwater time and space, rather than rushing it away.

You might already have seen sustainable drainage in action without realising it.

Some common examples include:

Water butts – collect rain from your roof so it can be reused
Rain gardens or planters – areas where water can soak into soil
Permeable paving – surfaces that let water pass through instead of running off
Swales or basins – shallow landscaped areas that temporarily hold water

Over time, our towns and cities have changed. We’ve replaced soil and green space with:

These surfaces push water away, so when it rains, water moves faster and reaches drains more quickly. That’s when problems can start.

Sustainable drainage helps take the pressure off by managing water earlier, before it overwhelms the system.

This happens when rain can’t drain away fast enough and starts to pool on streets, pavements, or gardens.

In some areas, rainwater and wastewater share the same pipes. When too much water enters at once, the system can overflow.

Sustainable drainage helps with both. By slowing rainwater down and reducing how much enters the drainage system at once, it:

Even small changes, spread across a neighbourhood, can make a noticeable difference.