Following the appearance of cyanobacteria blooms at the Romwiss beach at the Upper-Sûre lake, monitoring of bathing areas has increased.


A proliferation of cyanobacteria has been detected in Weiswampach lake. The presence of bacteria Microcystis sp. et Anabaena sp. has been confirmed by the LIST research centre. These could cause health issues among humans and animals, producing toxins. A concentration of 10 μg / l of microcystin was measured, exceeding the alert threshold of 4 μg / l.

Due to this discovery, all bathing and nautical activity in Weiswampach lake has been suspended with immediate effect.

The Water Management Administration, in consultation with the Health Directive, has recommended that the public:

- do not allow dogs or other pets to drink the lake water,

- and do not consume any fish caught within these waters.

Read more about blue algae here.


The bathing and other nautical activities ban, confirmed on 27 August 2019 for the "Rommwiss" beach, must be adhered to. With regard to the other official bathing beaches located at the Upper-Sûre lake, bathing is currently allowed.


With regards to the Remerschen bathing ponds, no trace of blue algae has been discovered and bathing is still allowed at this stage. Any potential ban will be reported to the public in the press.

The Water Management Administration will have up to date reports on the situation for all bathing areas on their website ( Leaflets on the topic of cyanobacteria are available for download.