IT’S official: local beaches from Milford-on-Sea to Purbeck have some of the best quality bathing water in the country.

Around 500 beaches and inland swimming spots in England and Wales have been rated by the Environment Agency after undergoing testing last year.

So on the next hot, sunny day, anyone who fancies a dip can go online to see pictures, maps and details before deciding where to go.

The new profiles at environment-agency.gov.uk show that all of Bournemouth, Poole, Christchurch and Purbeck’s beaches, plus Milford and Barton in Hampshire achieved the highest possible rating.

A record number of beaches and inland bathing waters reached the top EU standard last year – eight out of 10, compared to just three in 10 in 1990.

The huge improvement has come about following about £8 billion of investment to upgrade sewage systems and reduce pollution.

But Ed Mitchell from the Environment Agency said: “We are not complacent. The agency is working hard to tackle all sources of pollution, alongside beach users, local authorities, farmers and water companies.”

Along the urban section of the coast, the agency highlights a number of emergency or storm overflows that discharge into the sea.

The overflows prevent homes from being flooded with sewage after heavy rain or a breakdown at the local sewage pumping station, but can lead to a drop in bathing water quality.

The agency also warns that the effects of the wind and tide outside Christchurch Harbour can mean bathing water on nearby beaches reflects the quality of the rivers Stour and Avon, which take run-off from farmland.

Poole, Wareham and Lytchett Minster sewage treatment works were all upgraded by April 2003, along with the six storm overflows draining into the harbour.

The Holton Heath works will be receiving ultra-violet disinfection in 2013. Purbeck’s beaches have few issues, although the sea off Lulworth Cove and Kimmeridge Bay can occasionally suffer drops in bathing quality – especially after heavy rain.

According to the Environment Agency these rare instances are caused by runoff from nearby agricultural areas.

Fancy heading to one of Dorset’s award-winning beaches this weekend? Find out where they are, the closest parking and the best spots for swimming at dorsetbeaches.co.uk