Flood risk in Egham: what to check before buying

Known flood-prone areas in Egham

In February 2014 the Thames peaked on 12-13 February and around 250 homes flooded in Egham, part of 368 across Runnymede; severe flood warnings were not lifted until 17 February. Roughly a thousand homes went under across Chertsey, Egham, Staines and Weybridge that winter. Egham Hythe, Thorpe and the Chertsey riverside are the documented exposure.

These are documented historical risk areas. Risk assessment for any specific address requires checking the relevant national flood map at the postcode level. The city-wide picture above is context, not the answer.

Environment Agency flood zones explained

The EA bands river and sea flood risk into four categories: Very Low, Low, Medium, High. Each band is based on annual chance of flooding. Planning policy uses a parallel set of Flood Zones 1, 2, 3a and 3b. For Egham buyers, the zones matter for two reasons: lender appetite (where insurance is constrained) and resale risk.

13,954 homes in Runnymede are in some rivers-and-sea at-risk band, 29.1% of the stock. The River Thames Scheme is the long-promised answer — a flood-relief channel from Egham Hythe to Chertsey and a second section through Spelthorne, intended to reduce risk to around 11,000 homes and lower flood levels by up to 0.9 metres. It is not built. By early 2026 roughly £104 million had gone on development work without construction starting, and the scheme still needed a Development Consent Order. Do not price an Egham riverside property on the assumption that the channel exists.

• Zone 1 / Very Low: <0.1% annual chance from rivers or sea. Standard insurance, no buyer concern.
• Zone 2 / Low: 0.1%–1% annual chance. Standard insurance for most homes; check surface water separately.
• Zone 3a: 1%+ annual chance from rivers. Flood Re eligibility important on pre-2009 stock.
• Zone 3b: functional floodplain. Specialist insurer placement, lender appetite varies.

Surface water flooding in Egham

Surface water accounts for 3.8% of homes in a High or Medium band and 5,147 in some at-risk band. It matters, but on this stretch of the Thames the river is the question a buyer needs answered first.

Surface water is the form of flood risk most often missed because it isn't shown on the headline river map. Sellers often disclose "not in a flood zone" truthfully on the river map while surface water risk is medium or high. Always check both layers on the EA map.

What flood risk means for your mortgage and insurance

Lenders rarely refuse outright on flood risk. They care whether buildings insurance is available at standard cost. The chain runs:

1. Conveyancer's environmental search flags flood risk to the solicitor
2. Solicitor reports to lender, asks buyer to confirm insurance can be obtained
3. Buyer obtains a quote, shares the policy with the lender
4. Lender confirms drawdown if insurance is in place at acceptable cost

For Flood Re-eligible homes (most pre-2009 housing stock), insurance is available at near-standard rates. Post-2009 builds in high-risk areas, or homes with prior claim history, sit in the specialist insurer market. Quotes vary widely and the lender wants to see the policy before drawdown.

How to check your specific address

City-wide context is useful for orientation, but the only flood risk that matters is the one for the address you're about to buy. Three steps before your offer:

1. 1Open the relevant national flood map. For England, use check-long-term-flood-risk.service.gov.uk and read the available river, surface water and reservoir layers.
2. 2Read the seller's TA6 form for any past flooding disclosed by the current owner.
3. 3Get a buildings insurance quote at quote stage, not after exchange. Your lender will need it.

Frequently asked questions