Not allowed ...water regulations are not part of law. The are a set of sensible recommendations concerning the installation and operation of water systems to protect he drinking water supply. It is advisable to comply with water regulations especially if contravening a regulation does result in injury or illness then crninal and civil law will use the water regulations as a yardstick by which to prosecute. New work must comply under building regulations. Many parts legally on sale in uk are not wras approved