Government of Nova Scotia Government of Nova Scotia Nova Scotia, Canada


Drinking Water

Municipal Water Supplies

Approximately 60% of Nova Scotians receive treated drinking water from central groundwater or surface water supplies operated by municipal water utilities. Municipal public drinking water supplies are responsible for the delivery of water in accordance with provincial standards and for meeting their requirements for due diligence – making sure the water they deliver is properly managed and protected.

Approvals and Responsibilities

Nova Scotia Environment and Climate Change is responsible for issuing approvals for the construction and operation of water treatment and distribution facilities under the Activities Designation Regulations. In order to obtain an approval, a completed application formPDF Download Link (PDF:1008k) and supporting documentation must be submitted to the Department.

Active municipal public drinking water supplies are required to complete a System Assessment Report by April 1, 2023 to verify that each system is technically capable of achieving current environmental and public heath standards.

System Assessment Report and Terms of Reference

The purpose of a System Assessment Report is to verify that municipal public drinking water supplies meet:

  • current environmental and public health standards, which are frequently updated and enhanced for public health protection;
  • the minimum requirements set out in the Nova Scotia Treatment Standards for Municipal Drinking Water Systems, as amended from time to time.

A Terms of ReferencePDF Download Link (PDF:604k) document and Terms of Reference ChecklistPDF Download Link (PDF:960k) have been prepared to assist Approval Holders prepare these reports

Treatment Standards

The Nova Scotia Treatment Standards for Municipal Drinking Water Systems outline the requirements for municipal public drinking water supplies that use surface water, groundwater under the direct influence of surface water (GUDI), secure groundwater (non-GUDI), and that distribute treated water purchased from another municipal public drinking water supply.

The Treatment Standards document is available below as one large document or in nine sections.

The complete document is available herePDF Download Link (PDF:4.2mb)

Part I to VII of the Treatment StandardsPDF Download Link (PDF:464k) sets out the minimum requirements that apply to municipal public drinking water supplies in Nova Scotia. This includes source water protection, adequate treatment and distribution, operations and management.

Appendix A - GUDI ProtocolPDF Download Link (PDF:376k) outlines the process to be used to identify whether groundwater supplies are under the direct influence of surface water (GUDI).

MPA sampling modifications recommended by the Department are outlined in the following document:
Approved Modifications to the MPA Consensus Method for use in Nova ScotiaPDF Download Link (PDF:174k)

Appendix B - Natural Filtration GuidelinesPDF Download Link (PDF:119k) outlines the criteria for determining which groundwater supplies that are under the direct influence of surface water (GUDI) may be assigned a log removal credit for the natural filtration capacity of the aquifer. GUDI supplies that are assigned a log removal credit may apply the credit towards meeting the requirements of the Treatment Standard.

Appendix C - Process for Assigning Pathogen Log Reduction CreditsPDF Download Link (PDF:156k) outlines minimum treatment requirements and the process for assigning pathogen log reduction credits for enteric viruses and protozoa.

Appendix D - Log Inactivation Information and TablesPDF Download Link (PDF:3mb) provides log inactivation values for free chlorine, chlorine dioxide, ozone and UV disinfection.

Appendix E - Baffling FactorsPDF Download Link (PDF:174k) provides baffling factors for sample contact chamber designs.

Appendix F - Sample CT CalculationPDF Download Link (PDF:168k) provides guidance regarding how to calculate CT.

Appendix G - Technical Considerations for Filtration and DisinfectionPDF Download Link (PDF:148k) outlines specific requirements that apply for ultraviolet (UV) light disinfection, on-site generation of sodium hypochlorite, and membrane filtration.

Appendix H - Sampling RequirementsPDF Download Link (PDF:239k) outlines sampling requirements municipal public drinking water supplies must adhere to based on source water type.

Nova Scotia Environment has published a guide on Developing a Municipal Source Water Protection Plan. The document Designation of a Protected Water Area was developed to help municipalities and the general public better understand the potential role of designation in a municipal source water protection plan.

Our page on water withdrawal approvals has more information on how to apply for a surface water or groundwater withdrawal approval.

If you are planning any activities in these areas please contact the contact the appropriate municipal water utility: Municipal Drinking Water Supplies of Nova ScotiaPDF Download Link (PDF:1.1mb).

Municipal Public Drinking Water Supply Oversight

The Nova Scotia Utility and Review Board and Nova Scotia Environment have published a guide on municipal water utility oversight.

The guide was developed to help municipalities better understand their roles and responsibilities under the Public Utilities Act (administered by the Board) and the Environment Act (administered by Nova Scotia Environment).

Guidelines and Resources For Municipal Public Drinking Water Supplies

The following is a complication of resources to help municipal public drinking water supplies comply with the terms and conditions of their approval and the Water and Wastewater Facilities and Public Drinking Water Supplies Regulations