Prevent street sewer waste from backflowing into basements or low areas with the PVC 6 in. Backwater Valve. The backwater valve is lightweight and easy to install. The quick action flapper allows unrestricted uni-directional flow. Elastomeric gasket in the flapper ensures a watertight seal. Flapper can be easily removed and replaced if required. Access cap neoprene gasket provides a positive seal. Valve hub outlets fit 6 in. DWV pipe. Horizontal installation required, with arrows on top of the valve hub pointing in the direction of the flow of water. This backwater valve is a chemically resistant alternative to cast iron valves. Durable backwater valve is made of PVC plastic.