A new report from the European Environment Agency, or EEA, has highlighted the wildly varying quality of the continent's water resources, and said supplies "face an unprecedented set of challenges that threatens Europe's water security".

Although groundwater, which is the main source of drinking water, scores well in terms of quality, just one third of surface water is adjudged to be in good health, because of factors including overuse, climate change, habitat damage, and pollution, with EEA Executive Director Leena Yla-Mononen issuing a stark warning.

"We need to redouble our efforts to restore the health of our valued rivers, lakes, coastal waters, and other water bodies, and to make sure this vital resource is resilient and secure for generations to come," she said.

The study looked at 120,000 surface water bodies and 3.8 million square kilometers of groundwater across 19 member states of the European Union and Norway.

Air pollution, such as exhaust fumes, is a major pollutant, as are pesticides. The report identified agriculture as, by far, the biggest consumer of water in the EU, accounting for 59 percent, as opposed to 13 percent by households and services.

A water resilience initiative was proposed by European Commission President Ursula von der Leyen more than a year ago, but it never went ahead, following complaints from farmers about the additional work it would cause them.

"European agriculture needs to increase its use of more sustainable organic and agroecological practices, accompanied by incentives and a change in our food and dietary habits," the report noted.

But extreme weather conditions this summer prompted environment ministers from 21 of the EU's 27 member states to contact the commission in July, demanding "concrete action" over the issue of water security.

In light of recent devastating floods across much of Central Europe, the report noted that the impact of climate change was putting a strain on lakes, rivers, and coastal waters "like never before".

"Having a healthy aquatic ecosystem helps mitigate the impacts we're seeing of climate change," said Trine Christiansen, a co-author of the report and head of the EEA's freshwater and environment group. "The better the (water) situation we have, the more capable we are of handling these more extreme events."

She also mentioned another effect of climate change, the increasing occurrence of extreme drought conditions.

Malta and Cyprus were identified in the report as the most water-stressed EU member states, and Christiansen said "we are expecting (droughts) to get worse in the future … this is not a situation that Europe's water policy has prepared us well for".