John Guest is a British manufacturer of push-in fittings, pipe and plastic plumbing systems. Its industries and applications include drink dispensing, plumbing, pneumatics, compressed air Systems, water purification, drinks vending, automotive and telecommunications. Headquartered in Yiewsley, England, John Guest has offices in North America, Asia, Europe as well as the Pacific. It was founded in 1961 by John Guest. John Guest was acquired by Reliance Worldwide Corporation Ltd, in June 2018