and Llanrwst. Contingency plans for drought also name Llyn Conwy as the secondary source in the zone which, along with its own supply area, can feed part of the 'normal' Llyn Cowlyd (near Trefriw) supply area. A compensation discharge of 0.91 Ml/d would be required from Llyn Conwy.

The pH level of the lake is reported as pH 7.5257 on average, with calcium carbonate rates at 53.7 mg/L, hardness 3 °GH, free chlorine at 0.2853 mg/L