Flood risk across Merseyside
Merseyside is mostly urban, so surface water flooding during heavy downpours is the most widespread risk. The Mersey estuary and the low-lying Sefton and Wirral coasts also bring tidal flood risk, and smaller rivers such as the Alt and the Birket drain flat land that can be slow to clear.
Flood zones only show river and sea flooding, and they ignore flood defences. Surface water and reservoir risk aren’t part of the zones – check them on the Environment Agency’s long-term flood risk service, or get the full report, which covers every source.
Rivers that shape local flood risk
Main rivers are managed by the Environment Agency. Smaller watercourses and drainage are the responsibility of Knowsley Council and landowners.
River Mersey – The tidal estuary between Liverpool and the Wirral
River Alt – Knowsley, north Liverpool and Sefton
River Birket – North Wirral
Sankey Brook – St Helens
Ditton Brook – Knowsley and Halewood
Who manages flood risk here
Knowsley Council, Liverpool City Council, Sefton Council, St Helens Borough Council and Wirral Council are the Lead Local Flood Authorities, responsible for surface water, groundwater and ordinary watercourses. The Environment Agency manages main rivers and the sea, and issues flood warnings. The same councils also decide planning applications – and asks for a flood risk assessment in Flood Zones 2 and 3.
Getting a written answer for an address
The free check describes the area around your postcode. For a specific property, the full report checks your exact address against every flood dataset and gives you a dated PDF to share with your surveyor, conveyancer or insurer.
For planning decisions, your local council has the final say.
