The water is safe to swim in - for now. That "for now" is the key phrase in the Institute of Public Health's latest report on Macedonia's three lakes. The beaches of Lake Ohrid, Prespa and Dojran pass the test, and tourists can swim. But below the surface lurk sewage, septic pits and pesticides that nobody has dealt with for decades.

The biggest problem is exactly where we want it least - on Lake Ohrid, our only entry on UNESCO's World Heritage list. The report points to hotels, restaurants and private houses along the shore that dump wastewater into septic pits instead of the sewer collector system. In Radožda the situation is at its worst: some septic pits are emptied directly into the lake or sit so close to the shore that their contents seep into the water.

Lake Prespa fares better - at six monitoring points the risk of pollution is low. But there too, some facilities still use primitive septic systems, and the treatment plant near one children's holiday resort is not working. At Lake Dojran the main threat comes from agriculture: pesticides and chemical fertilisers from the surrounding fields seep into the groundwater, and from there into the lake.

The Institute's recommendations are familiar to the point of boredom: complete the sewer collector system, stop direct discharge, keep continuous monitoring. The problem is that these same recommendations have been repeated for decades - and stay on paper. How many reports have to be written before someone finally digs one sewer collector all the way?

"Safe for now" is a phrase with an expiry date. The lakes bear the consequences of infrastructure that was never finished and oversight that only kicks in during the summer season, when there are tourists and when somebody asks. If the UNESCO status falls, it won't fall because of one bad day - but because of decades of postponed solutions. And by then the phrase won't be "safe for now," but "too late."