The Water Supply (Water Quality) Regulations 1989 & 1991 made under these Water Acts specify the "wholesomeness" of water supplies. There are Water Quality Objectives laid down in accordance with these Regulations.

The Environmental Protection (Prescribed Processes and Substances) Regulations 1991 set out a list of prescribed substances that require close monitoring and control before they can be discharged to water. This is popularly called the "Red List".