Indebted Greeks and nervous Olympians could draw relief from the latest report, which finds the waters of Greece, so crucial to much-needed tourist revenues, among the most pristine in Europe and confirms London's Serpentine is clean enough to swim in.
Overall, 92.1 percent of bathing waters in the European Union meet minimum water quality standards, but some nations, including the EU's home Belgium, have work to do.
Along with Bulgaria, Latvia, Luxembourg and the Netherlands, Belgium had relatively few sites, especially inland, conforming to the standards of the Bathing Water Directive.
Some five percent of Belgian sites were non-complying or poor and 9.1 percent banned or closed, while in the Netherlands 10.1 percent were non-complying or poor and 0.3 percent banned or closed.
Luxembourg did not have any non-compliant sites, but 45 percent of its bathing waters were banned or closed.
At the other end of the scale, with more than 90 percent of sites meeting the most stringent standards, were Cyprus, Croatia and Malta, as well as Greece.
"A clear majority of Europeans are concerned about water quality issues," Environment Commissioner Janez Potocnik said.
"We must therefore continue our work to ensure our waters are appropriate for all legitimate uses - from bathing to drinking - and that the overall aquatic ecosystem is in good health."
The Commission, the EU's executive arm, and member states have been working for years to combat problems caused by industrial waste-water and sewage.
A decline in east European manufacturing industry during recession contributed to the improving trend.
Since 1990, the number of coastal bathing waters not complying fell from 9.2 percent to 1.5 percent in 2011.
Over the same period, the number of inland bathing areas not complying decreased from 11.9 percent to 2.4 percent.
Apart from the headline figure of 92.1 percent of all sites now meeting at least minimum standards, the report found 77.1 percent were of excellent quality in 2011 - that is, complying with the toughest standards, an improvement of 3.5 percentage points on the previous year's data.
The share of non-compliant bathing waters, at 1.8 percent, also rose very slightly year-on-year - showing a 0.1 percentage point increase from 2010.
Initial EU legislation was adopted in 1975 and revised when the bloc adopted a new bathing water law in 2006, with a more pro-active approach, to bring the public into the debate.
Each year, EU body the European Environment Agency and the Commission publish a report based on laboratory analysis of bacteria, which can indicate the presence of pollution, chiefly from sewage or livestock waste.
More than 22,000 sites are classified as compliant with mandatory values, compliant with the toughest guidelines or not compliant.
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