The EU bathing water classification explained

How is the rating determined?

During the bathing season, water authorities regularly measure two groups of bacteria that indicate faecal contamination: E. coli and intestinal enterococci. The classification is calculated over the measurements of the last four bathing seasons combined — so one bad summer does not immediately drag the rating down, and one good summer does not immediately restore it.

The result is one of four classes: excellent, good, sufficient or poor. Locations rated 'poor' typically get negative swimming advice or improvement measures. The Netherlands traditionally scores high in European comparisons: the vast majority of Dutch locations are rated 'excellent' or 'good'.

Classification versus current advisories

The EU classification reflects structural quality over several years, not today's conditions. A location rated 'excellent' can temporarily have a blue-green algae warning, and vice versa. Always look at both: the annual rating for long-term reliability, and the current measures for right now. This site shows them side by side on every spot page.

The rating is published annually by the European Environment Agency (EEA). Publication lags the bathing season by a few months, which is why the rating year is always shown next to the label.

How this site uses the classification

Besides showing the rating per spot, this site uses the classification as the basis for the 'Top rated' selection: official locations rated 'excellent' with the best facilities, per province. That way you can quickly find the proven cleanest spots in your region.

Frequently asked questions

What does 'excellent' on the blue sign mean?

That the bacteriological water quality over the last four bathing seasons was well within the strictest standard of the European Bathing Water Directive. It is the highest of the four classes: excellent, good, sufficient and poor.

Does 'excellent' mean it is safe to swim today?

Not necessarily. The classification covers several years; current issues such as blue-green algae are separate from it. Always check the current advisories on the signs or on zwemwater.nl — this site shows both side by side.

Why does the rating show an older year?

The European Environment Agency publishes the classification a few months after the bathing season ends. The most recent official rating can therefore cover an earlier season; the year next to the label makes that transparent.