More than £100m is needed to improve water resources in the East of England if plans for 500,000 new homes are to be realised, an expert has warned.
Water shortages could slow down investment in housing
The area is expected to see half a million new homes built between now and 2021, according to the government's draft regional strategy.
This week a conference will look at water shortages in the East of England.
Leading consultant Chris Mead is due to tell the meeting that action is needed to ensure a continuing water supply.
He told BBC News that it was vital that investment was put into plans to enlarge Abberton Reservoir in Essex (a site of special scientific interest), in spite of opposition by conservation groups.
Mr Mead, senior technical director for international consultants WSP Development and Transportation, said more water from the River Trent needed to be brought down to East Anglia.
He is giving a talk "Water as a Scarce Resource: A Threat to Growth Targets in the East of England" to a Royal Town Planning Institute conference in Cambridge on Wednesday.
Mr Mead said he would be highlighting the fact that the East was the driest region in the UK, but had the fastest growing population.
He said that if the 508,000 new homes were to be built, huge investment in water resources was needed.
Mr Mead said the government and OFWAT needed to help the water companies fund the changes.
"It will be a significant cost. It is likely to cost hundreds of millions of pounds," he said.
Mr Mead said if the investment was not put in, then there would be a "slowdown on housing growth".
"But regional growth should not be constrained by water concerns," he said.
On Friday a report to the East of England Regional Assembly (EERA) on water resources is due to be released.