Hundreds of new homes have been given the go-ahead in the past few years, despite official warnings they will be at risk of flooding, figures suggest.
More than 1,200 residential properties have been granted planning permission in the last five years against the advice of the Environment Agency over flood risk, the figures from the organisation show.
The agency's advice is taken by local planning authorities for the overwhelming majority of houses, but the number of homes being built despite flood concerns may be higher than the figures show.
There are hundreds of applications a year where the Environment Agency lodges an initial objection, but is not informed of the planning decision.
The number of homes where EA was informed and its advice was overruled was 124 in 2011/2012, jumping up to 508 in 2012/2013 before falling to 230 in 2013/2014 and plateauing at 183 for the past two years.
Homes at risk of flooding which have been constructed or converted into residential properties since January 2012 do not count towards securing partnership funding for flood protection schemes under current government rules.
Details of initial objections to planning schemes also suggest some developers are not fully taking flood risk into account when drawing up plans, with the agency raising concerns in the past year over hundreds of new homes due to a risk to life or property.
Martin Tett, environment spokesman at the Local Government Association, said: "Local authorities throw out planning applications which are reckless and irresponsible.
"Councils are generally opposed to building property on floodplains and over 98% of the 77,125 new homes in 2014/ 15 had planning outcomes in line with Environment Agency advice.
"Where building does take place on a floodplain, the local authority would need to be reassured that adequate defences were in place so that the risk of flooding would be minimised and that measures would be in place to prevent or minimise water from entering homes."