Ready for assembly plastic sump made of corrosion-resistant polyethylene in monolithic construction without sealing surfaces, optionally with telescopic extension. With deposit-free pump chamber geometry and lifting brackets for easy removal and transportation. Anti-buoyant for ground water levels up to surface of ground without additional concrete weights provided by the customer. Submersible drainage pump with integrated non-return valve, mounted directly on the discharge pipe line and placed on the chamber floor. Bushing gate valve with optional operating extension. Incl. chain as pump lifting device. Pump chamber cover in accordance with EN 124 in categories A 15 and B 125 can be installed directly onto the pump chamber without a weight distribution plate, optional class D 400 (with customer-supplied weight distribution plate) available.