Water pipes or fittings must not be laid or installed in any contaminated environment such as in drains, sewers, foul soil or refuse, regardless of any protection to the pipe or fittings. Fittings and pipes made of plastics or other materials, which are likely to be damaged by exposure to oil, petrol or other contaminants should not be laid in contaminated ground, or should be suitably protected. Advice is given on the selection of materials for water pipes in land, which may become contaminated in UKWIR's "Guidance for the Selection of Water Supply Pipes to be used in Brownfield Sites" (Ref 10/WM/03/21). Other advice is given in 'Pipeline Selection for Use in Contaminated Land – Best Practice Manual', published by UKWIR.