Polyvinyl chloride is the most common pipe material used in onsite wastewater treatment systems. PVC pipe manufacturers must follow accepted standards for dimensions and material strength. Onsite system installers must have some understanding of these standards in order to ensure that the correct PVC product is selected for the job.Nominal diameters — All pipes have a nominal diameter. This value is typically the nearest 1/4 or 1/2 inch value of the actual internal diameter. These nominal diameters are “name” only. By the standards listed below, each pipe size and material type must be manufactured with an internal and external diameter that meets
