Basingstoke MP Maria Miller has slammed failures to tackle pollution of the River Loddon.
She is demanding more investment in sewage treatment works and has urged the Environment Agency to clean up the river.
Her call comes as borough councillors prepare to outline house building targets and amid fears that new developments could add to the contamination.
She said: “The pollution of the River Loddon needs to be addressed with urgency. It is not good enough just to say that the situation is not getting any worse – we need to push for an improvement in the river quality.
“Further investments is needed to reduce the level of contamination before the sewage treatment works at Chineham can receive more waste from any significant new housing developments.
“This needs to be seen as a priority and is a very real constraint on further house building.”
The 28-mile river runs under Festival Place before emerging at Eastrop Park and snaking past Old Basing, Chineham, Sherfield-on-Loddon and Stratfield Saye. It then flows into Berkshire and joins the River Thames.
According to a water quality report drawn up in 2009, phosphate pollution was six times higher than EU regulations allow due to treated sewage flowing into the water from the town.
And earlier this year, councillors cited pollution of the Loddon as a reason to push for lower housing numbers.
Despite the soaring phosphate levels, the Environment Agency has said no work to improve the water quality will take place for another four years.
The agency said: “As part of this first planning cycle, the Environment Agency is currently conducting a number of investigations in the Loddon catchment. In particular, we are collecting evidence of biological impacts caused by poor water quality. This evidence will help to identify and drive further improvement actions should they be needed .
“Improvements to sewage treatment works discharges are currently undertaken during water companies’ business cycles set out by OfWat, the next cycle being 2015 to 2020.”
