KWH is an active contributing member of the Plastic Pipe Institute Inc. (PPI). Founded in 1950, PPI is the major trade association representing all segments of the plastics piping industry. PPI members share a common interest in broadening market opportunities that make effective use of plastics piping for water and gas distribution, sewer and wastewater, oil and gas production, industrial and mining uses, power and communications, duct and irrigation.

PPI was instrumental in the establishment of uniform testing and design criteria that became the foundation for all current applications of plastics piping. In addition they conceived the methodology for the rating of a materials long-term strength and the adoption of standard preferred numbers to state specific properties. They also engineered the first code of acceptance for plumbing, industrial, commercial and gas distribution.