There is a picture in the Times that sums it up: a flooded field with a sign at then entrance announcing that it is shortly to be the site of an exclusive development of 4 and 5 bedroom executive homes. I'm not in the property business, but I reckon that they will rather more difficult to shift than the builder was expecting. Of course, this does not help the poor people who bought newly-built properties on flood plains from developers who relied on the fact that floods don't happen that often, honest.
The government has a policy of building a great deal of housing, and the events of the last few days will have reduced the amount of potential building land, as the danger and likelihood of flooding is reappraised, even where no floods have not yet occurred. For some this will be the salvation of the character of their communities, as the only bulldozers that they will now see will likely be those shoring up flood defences. Others, protected by chance lie of the land may see much more building. In all cases, there will be much more pressure on available brownfield sites. In the short term, the government is taking a pasting for a lacklustre response to the crisis. The longer-term effects on policy are likely to be more significant.