Abstract: An animal drinking water supply apparatus includes a cylindrical container in the form of a culvert with a flexible bowl inserted into one end of the culvert so that a horizontal upper edge of the bowl engages over the edge of the culvert with the bowl sitting inside the culvert. A transverse support member is connected across the inside of the culvert to support the base of the bowl. The support member comprises a rectangular tube within which is provided a liquid heat transfer medium and a heating element so that the upper surface of the support member upon which the bowl rests is heated to avoid freezing of the water. The depth of water is maintained within limits by a micro switch detecting the flexing of the bowl in dependence upon the weight of water.