Borgwallsee is a lake in Mecklenburg-Vorpommern, Germany, at an elevation of 13.2 m (43 ft). Its surface area is 3.89 km2 (1.50 sq mi). The average depth is 2.4 m (7 ft 10 in). Apart from the woods on the southern shore, the area surrounding the lake is used widely for agriculture. Borgwallsee is a drinking water reservoir serving the city of Stralsund. As such, water activities are restricted and bathing is allowed only in designated areas.