Blackpool North and South beaches, as well as those at Morecambe, St Anne's and Cleveleys in Lancashire, and Colwyn Bay and Llandudno in Clwyd, are among 19 beaches in the 'worst' category of the survey by the Tidy Britain Group.
Others marked out for unacceptable water quality and beach safety included Swansea, Deal, Rhyl, Southport, and Looe East.
After its two-year survey, the group gave marks out of 100 to 100 beaches. Those rated in the 80 to 100 range were classified as the best. Those over 60 as 'very good'; those over 60 but with poor water as 'good beach, shame about the water'; those between 40 and 60 but with guideline water quality as 'disappointing'; and those that scored under 60 for beach management and failed water quality tests as 'worst'.
Two-thirds of beaches were in the top two categories, but only one scored full marks for both water quality and beach management - Poole (Sandbanks) in Dorset. Five others reached the 'best' category. These were Benone in Co Londonderry; Cefn Sidan, Dyfed; Oddicombe, Devon; Sheerness, Kent; and Woolacombe, Devon.
Graham Ashworth, director general of the group, said some of the poorest beaches were let down by the quality of their water. This is partly a historic problem for the regional water company, North West Water, which is trying to correct years of under-investment that have resulted in standards below European guidelines.
'In some cases the local authority still makes tremendous efforts, and these fall into the 'good beach shame about the water' category of our report. But I do wonder whether the poor water quality in the North-west has an adverse effect on the amount of investment local authorities put into the beaches themselves,' Professor Ashworth said.
He was particularly concerned that 43 per cent of the beaches carried some trace of sewage-related litter. 'This again is partly a water company problem, but once sewage gets on to a beach it has to be cleaned up and that's a question of beach management.' Another area of concern was the lack of safety features and dearth of public information at some beaches.
The Tidy Britain Group, which co-ordinated the two-year study, said it was the most rigorous of its kind conducted in the UK. The survey found that 16 per cent of beaches had a complete lack of safety provision. Half did not use flags to indicate safe bathing; half had inadequate wheelchair access; and 40 per cent had inadequate toilet and washing facilities.
The group awards Blue Flags to beaches every year as part of an assessment of European resorts, but found that beaches that did not enter were avoiding scrutiny. 'Those that kept their heads down were not being assessed, while some that entered were getting stick for not measuring up,' Professor Ashworth said. The new survey will be done on an annual basis.
Jane Seddon, assistant director of tourism and services for Blackpool borough council, said the council spent pounds 200,000 a year on beach management. She said schemes planned by North West Water for the next two years should improve water quality.