Warrington-based United Utilities will prioritise improvements to the northwest's sewer systems as part of plans to upgrade the company's existing infrastructure.

This proposal, which will be submitted to regulator Ofwat, follows a survey of 500 regional businesses, reports the North West Business Insider.

Between 2010 and 2015, the company wants to invest £4 billion. Of this, £2.4 billion would be for waste services, with £1.6 billion for water services.

Clive Elphick, managing director of assets at United Utilities, told Insider that 500 businesses were consulted on the investment.

"Businesses told us they were more likely to pay for an upgraded waste water service," he explained.

Last month, United Utilities' chairman Sir Richard Evans said trading was in line with the group's expectations after delivering "good" profit growth and operational improvements.

The company is now on course to return £1.5 billion to shareholders.