It’s perfectly clear North Cardiff reservoir waters are quality!

Bathing water quality in Wales has improved significantly over the past two decades, and Llanishen Reservoir is up there with the best.

In just their first year of being designated as a bathing water, the reservoir has received “excellent” status in Natural Resources Wales’s (NRW) Bathing Waters classifications.

The 2025 classifications have been provided by NRW in accordance with the Bathing Water Regulations and are based on monitoring data collected over the 2025 bathing season, from 15 May to 30 September, and the preceding seasons, where appropriate.

The bathing water programme is designed to give an indication of water quality, rather than an absolute measure of its condition.

There are 112 designated bathing waters in Wales, and Llanishen Reservoir has become one of the 98% assessed as meeting the standards and one of 78 classed as “excellent”.

This is even more impressive as 2015 was the first year stricter standards were applied in Wales, meaning bathing waters must now achieve even tougher water quality targets than previously. 

This will be welcome news to the reservoir's visitors who take part in activities, such as open-water swimming, canoeing, paddleboarding and sailing.

Deputy First Minister with responsibility for Climate Change, Huw Irranca-Davies, said:  “I’m particularly encouraged by a standout performance from one of our newly designated sites, Llanishen Reservoir in Cardiff, which has achieved ‘excellent’ status in its first year– a remarkable achievement.”

You can find out more about Llanishen Reservoirs 2025 Bathing Water Profile here.