The exemption is only available provided the amount of drinking water supplied is no more than 30% of the amount of drinking water produced by the operator.
Dim ond ar yr amod nad yw swm y dŵr yfed a gyflenwir yn fwy na 30% o’r dŵr yfed a gynhyrchir gan y gweithredwr y mae’r esemptiad ar gael.