Holidaymakers could be putting their health at risk by swimming in pools at some of Europe's most popular resorts, a survey suggests.
The researchers looked at pools in Majorca and Corfu
Researchers from the Consumers Association tested 80 pools in Majorca and Corfu for Holiday Which? magazine.
Just two were given a clean bill of health. One in four was condemned as a health hazard.
Kim Winter of Holiday Which? magazine said: "This is posing a serious health hazard to holidaymakers."
The tests were carried out on pools in Alcudia and Puerto de Pollensa in Majorca and Sidari in Corfu.
Six pools were found to be heavily contaminated with faecal bacteria, possibly caused by
babies or toddlers fouling the pool.
This would have put swimmers at risk of developing of range of health problems, including diarrhoea, sickness, stomach cramps and fever
Chlorine levels were so high in seven pools that they risked bleaching bathing suits and causing irritation to the eyes and skin of swimmers.
Five pools contained no traces of disinfectant at all leaving bathers at risk of picking up infections from bacteria in the water.
A further 29 pools were found to be a potential risk to health.
Kim Winter, managing editor of Holiday Which?, said holidaymakers should be aware of the risks.
"No definite scientific research exists linking levels of contamination with risks of illness, but none of our experts would have swum in any of the worst-rated pools we tested.
"Our stomach-churning evidence of gross bacterial contamination shows the apparent incompetence of most hotels at maintaining effective levels of water disinfectant in their pools."
Mr Winter called for new EU rules and inspections to monitor water quality in swimming pools as currently happens for beaches.
The UK's Federation of Tour Operators welcomed the survey. A spokesman said its members would support EU-wide inspections of public swimming pools.
"FTO members expect high standards from hoteliers with whom they contract," he told BBC News Online.
"The FTO works closely with hoteliers and overseas governments around the world on this as well as a range of other holiday safety issues.
"The key requirement, however, is that of ensuring ongoing day to day compliance with swimming pool water quality standards and it would help if new EU required inspection regimes were rapidly introduced."