-Non return valve, Why fit a non return valve? From the 1st January 1989, water bye-law 18 came into effect requiring any outside tap with a hose pipe fitted to it, to be protected from the dangers of contaminated water being siphoned back into the mains. This is acheived with the aid of 'non return' or anti-backflow' device such as the Hozelock non return valve. Non compliance can result in heavy fines. Fits directly onto tap.
