Clean Check ABS extendable backwater valves prevent sewage backup into a residence or building as a result of a plugged sewer system, excess volume in the system or groundwater flooding. Easy to install; ABS clean check backwater valve installs discretely outside up to 12' below ground level. Above ground outdoor backwater check valve maintenance accessibility eliminates hidden access indoor applications, and the sewer odor and mess of indoor maintenance. Clean check ABS extendable backwater valve; 4" with included inground flapper; manholes not required; prevents sewer backup. FOR THE TRADESMAN: RectorSeal is recognized as a leading provider of quality solutions for the professional trades serving heating, ventilation, and air conditioning (HVAC/R), plumbing, electrical, and construction markets.