The Cataraqui Source Protection Plan developed under the Clean Water Act, 2006 (Act) directs local efforts to keep sources of drinking water clean and plentiful. Some activities have the potential to harm the quality or quantity of drinking water and are known as drinking water threats under the Act. Under the Act, Part IV relates to the regulation of certain drinking water threat activities (existing and future) that are or may be considered due to their potential to pollute the drinking water source.

Part IV policies in the Cataraqui Source Protection Plan apply to drinking water supplies that have been identified as more vulnerable, where significant drinking water threats can exist. This means that Part IV policies apply only to portions of certain vulnerable areas, which represents less than one per cent of the total CSPA.

Under Part IV, significant drinking water threat activities are managed using the following tools, prohibition, risk management plans, and restricted land uses. These Part IV policies fill gaps where significant drinking water threat activities cannot be addressed by existing planning or regulatory tools.