With the region in the grip of a severe drought, opponents of large-scale housing plans around Norwich have questioned whether there will be enough water for an enlarged future population.

Campaigners said the hosepipe ban announced by Anglian Water this week proved there was already barely enough water to supply existing households.

So they have asked how Norfolk's infrastructure can possibly cope with the 37,000 new homes outlined in the joint core strategy (JCS) developed by the Greater Norwich Development Partnership (GNDP) to be built by 2026.

Concerns have also been raised that the rising demand from new households could lead to over-abstraction from protected rivers like the Wensum, which currently has 128 licensed abstractions from its catchment, including nine for public water supply.

High abstraction can be a problem for the river's wildlife, especially in the lower reaches below Costessey from where most of the public water supply is taken.

Environment Agency officers reassured objectors that existing limits to protect rivers would not be lowered to accommodate new housing. And Anglian Water said it would continue to work with developers to ensure enough infrastructure and water-saving measures were in place to meet the company's obligation to provide essential services for any new housing.

Phil Emery is a member of the Hethersett Our Way campaign group, which is contesting plans submitted to South Norfolk Council for 1,196 homes in the village, south of Norwich.

'The situation is only going to get worse,' he said. 'I think this is going to be the first of many hosepipe bans.

'We are talking about 37,000 new houses in the JCS, and where is their water coming from? It will need to come from somewhere and the levels in the rivers are getting lower and lower. My preference would be that any water we do have should be used by farmers to irrigate their crops.'

John Clare of Anglian Water said: 'We recognise that population growth and climate change are the two biggest challenges we face, but we have been facing up to them for some years. Investing in infrastructure is part of the solution, but only a part. Demand management is just as important.

'We supply 1.2 billion litres of water a day, exactly the same amount as we did 20 years ago, even though the population across our area has grown by 20pc in that time.

'Effectively we have saved enough water in that time to supply 20pc of the population, and household efficiencies and water metering have played a really big part in that.

'In Norwich, we opened a new water treatment works in East Hills at Costessey last year to further strengthen the security of the city's water supplies.'

An EA spokesman said: 'The JCS includes a policy requiring water efficiency measures to be included within all new development. Anglian Water Services also provided assurances that sufficient water would be available, when required, for growth.

'If any new or variation to existing abstraction licences were to be applied for on the Wensum we would assess it as we do any other application. This means we would assess the effect on the environment and other abstractors to make sure that the extra abstraction would not cause a problem. Any new or further abstraction affecting the Special Area of Conservation of the river is however, unlikely to be successful.'

John Fuller, leader of South Norfolk Council and former chairman of the GNDP, said: 'Within the last two years, Anglian Water has spent millions of pounds securing the supply for the Norwich area in anticipation of these houses. That was all taken into account in our water cycle study, which can be viewed online at www.gndp.org.uk.

'All development must take into account conserving and recycling water, and also what to do if there is too much rain to avoid flooding.'

The EA objected to the Hethersett application because of concerns that the development's surface water management scheme was insufficient to avert flooding risks.

The applicant, Hethersett Land Ltd, responded to say that it was working with environmental officers to update its flood risk assessments, and that it had committed to work with AW to develop a site-wide rainwater recycling strategy to collect water within 'attenuation ponds', from where it could be re-used in the proposed school allotments and football club.