A Pop-Up Water Relief Valve (also commonly known as a Pop-Up Drainage Emitter) that is normally closed except when there is a build up of hydrostatic pressure. As the drainage pipes fill and build up slight pressure, the cover rises to allow the excess water to escape. Once the water is discharged the pressure drops and a stainless steel spring automatically retracts the cover to its closed flush position. The flush design of the product ensures that it blends well into the surrounding area. The Pop-Up body is manufactured from structurally foamed High Density Polyethylene (HDPE) with a UV inhibitor to reduce sun damage, while the Elbow (which comes with a pre-drilled hole to drain excess water) is manufactured from PVC and the Adapter from High Impact Polystyrene (HIPS). Typical application for this product is at the discharge end of the drainage pipe. Can be installed in either a vertical or horizontal position. Connects to 3″ & 4″ Sewer & Drain Pipe (ASTM D2729), 3″ & 4″ Corrugated Pipe and 3″ & 4″ Triple Wall Pipe.