The map, which shows the level of flood risk houses in different areas should expect, is one of many factors insurers take into account when insurers price cover.
Government-backed scheme Flood Re will help some homeowners in high-risk areas to access affordable insurance. Insurers will be able to pass on the flood risk element of the policy to the programme, and premiums will be capped based on each property’s council tax band.
However, the scheme does not cover homes built after January 1, 2009 or commercial properties, or properties which are let.
The impact of the flooding on insurers has been great. Direct Line has said it expects to pay out up to £140m to claimaints after the flooding at the end of the year, £35m more than their annual prediction for weather-related claims.
Flood map expert Jill Boulton, a director at Yorkshire-based JBA Risk Management, said she expected the Environment Agency’s maps to grow following the extensive flooding over Christmas.
“I’m anticipating that more properties will be included, because of global warming and the conditions that we’re seeing.
“It’s difficult to know what to prepare for. What happens when you get levels that are expected to happen every one in 100 or one in 200 years? What level of defence do you go for?
“I’m guessing that they’re going to review a lot of their data. What if what happened in Cumbria was to happen in the south east?
She said that while flood mapping was till now based on historical data, in future it is likely to include more provision for climate change and less predictable occurrences. This would have the effect of extending the at-risk areas.
She said Flood Re would help some homeowners, but insurance might become unaffordable for those in new-build houses, or commercial properties – which includes buy-to-let and blocks of flats.
Some homeowners had previously criticised the maps for placing houses in high-risk areas and making their premiums too high, leaving them with large bills after flood damage.
A spokesman for the Association of British Insurers said the rules about newer houses were intended to discourage developers to build in high-risk areas.
A spokesman for the Environment Agency said: “Flood insurance cover is critically important in reducing the impact of flooding on people. We review our flood data constantly and re-examine it after flooding incidents.”