Cyprus, Malta and Luxembourg offer Europe’s best swimming water, a report by the European Union’s environment watchdog says.

The Copenhagen-based European Environment Agency (EEA) and European Commission analysed water quality in more than 21,000 beach, river and lake sites across Europe during 2014, including non-EU members Switzerland and Albania.

The tests showed that “all bathing waters achieved excellent status in Cyprus, Malta, and Luxembourg”, the annual report said.

Cyprus, where the tourism industry is a mainstay, has for several years topped the survey. All its 112 coastal swimming sites yet again scored 100 per cent.

The water quality was excellent in at least 90 per cent of sites surveyed in Greece, Croatia and Germany, the study added.

The report said 95 per cent of bathing waters in the 30 countries surveyed met minimum EU water quality standards – a slight increase compared with 2013, while 83.3 per cent were excellent, also a slight increase on the previous year.

Meanwhile, just under 2 per cent of bathing waters – a total of 409 – were found to have poor water quality.

Countries with the highest rates of bathing waters failing to meet EU standards were Estonia (5.6 per cent), Ireland (5.1 per cent), the Netherlands (4.9 per cent), and Sweden (3.6 per cent).

The samples are tested for two types of bacteria, Escherichia coli and intestinal enterococci. Escherichia coli – or E coli – can cause diarrhoea and other intestinal illnesses.

Peter Kristensen, project manager with the EEA, said the two kinds of bacteria were “good indicators” of contamination due to human waste.

Main sources for poor water quality include pollution from sewage or waste from livestock or farmland. Heavy rains or floods can result in more pollution being washed into rivers, lakes and seas, and cause sewerage systems to overflow, the report said.