Low Flood Risk
Zone 1 in England
Flood Zone 1 is the lowest of the Environment Agency's flood zones for England. It covers land with less than a 1 in 1,000 (0.1%) annual chance of river or sea flooding. Zones cover rivers and the sea only, not surface water from heavy rainfall. Wales, Scotland and Northern Ireland map flood risk under their own schemes.
What This Means
River and sea flooding is very unlikely at this address. You should not need flood barriers, raised electrics or other resilience work for that source. A significant share of flood damage still happens in low-risk areas, mostly from rainfall overwhelming drains. Building here is barely constrained, and most householder applications need no flood risk assessment. Larger sites need one, as do plans that make the site more sensitive to flooding. This does not normally affect mortgage approval, buildings insurance or resale.
Practical Advice
- Check this address on the Environment Agency's long-term flood risk service for its surface water rating.
- Ask the seller on the TA6 property information form whether the street has ever flooded from rainfall.
- Ask your surveyor where rainwater drains on the plot, particularly if the ground falls towards the house.
- Ask your conveyancer's environmental search whether the site sits in a critical drainage area.
Key Points
- A site of 1 hectare or more needs a flood risk assessment even in Zone 1; an ordinary house plot is nowhere near that.
- Converting an outbuilding here into a dwelling can require a flood risk assessment where the plot is also at surface water risk; a rear extension on the same plot would not.
Additional Information
The Environment Agency rebuilt the Flood Map for Planning in March 2025 on NaFRA2 modelling. Some addresses changed zone as a result. The rebuilt map carries defended and undefended extents and climate-change allowances, which the old map did not. The link below covers England only.