More than half the swimming pools and spas tested in a nationwide survey have been criticised for poor water quality.

The investigation, for consumer magazine Which? was carried out randomly by members of the Institute of Sport and Recreational Management.

They took 61 water samples, and described less than half as good.

The rest were either described as "adequate", while still falling outside accepted parameters, or worse.

Nine of them, they said, "posed a health risk" - while three of these were described as "potentially serious".

These were the pool at Dorking Sports Centre in Surrey, and spa baths at Fitness First in Shrewsbury, and Tudor Grange in Solihull.

Sweat, faeces and urine

Common contamination was from sweat, urine, faeces and mucus - and residues of creams and shampoos.

There were also low levels of bacteria called Pseudonomas aeruginosa, which can cause ear and skin infections.

The water sample from Fitness First had a high count of bacteria - 30 times the maximum recommended level.

The other two samples deemed to represent a high risk involved poorly applied disinfectants.

Conditions in spa pools were worse than in swimming pools - standards were inadequate in seven out of 21 spa pools, compared with just two out of 40 pools visited.

At the moment there is no specific legislation covering water quality in pools or spas.

Which? is now backing calls from the institute for the introduction of mandatory regulations on water quality to be introduced.

Ralph Riley, an institute member, and chairman of the Pool Water Treatment Advisory Group, said: "We need regulation if we are ever to ensure standards of pool water quality in the same way that we have for drinking water and coastal waters.