The Frankenteich (also called the Sägemüllerteich) is an old reservoir in the Harz Mountains of central Germany. It was constructed in 1716 under the direction of mining director (Bergwerksdirektor), Christian Zacharias Koch, for the mining industry and is the largest pond in the Lower Harz. Since 1901 it has supplied drinking water to the village of Straßberg. It impounds the Rödelbachgraben, which discharges into the Selke in Straßberg. A mining ditch runs past the foot of the dam from the Kiliansteich which, like the Frankenteich, belongs to the heritage area designated as the Lower Harz Pond and Ditch System.