The Design Guidelines for Drinking-Water Systems were prepared under the guidance of the Ontario Ministry of the Environment (MOE) Drinking Water Technical Working Group with the assistance of XCG Consultants Ltd. in association with Hydromantis Inc. This document underwent review by various branches of the Ontario Ministry of the Environment and the following stakeholders and reviewers.

Ministry of the Environment Drinking Water Technical Working Group:

  • George Lai, M.Eng., P.Eng., Standards Development Branch, MOE
  • Janusz Budziakowski, M.Sc., P.Eng., Safe Drinking Water Branch, MOE
  • Tony Edmonds, Ph.D., Ontario Clean Water Agency
  • Judith Patrick, Standards Development Branch, MOE

Stakeholders and Reviewers

  • William B. Anderson, Ph.D., Academia (University of Waterloo)
  • Steve Burns, P.Eng., Ontario Water Works Association
  • Karu Chinniah, M.Sc., P.Eng., Alberta Environment
  • Robert Dumancic, M.A. Sc., P.Eng., Standards Development Branch, MOE
  • Andrew Farr, P.Eng., Association of Municipalities of Ontario
  • Bill Hargrave, Ph.D., P.Eng., Consulting Engineers of Ontario
  • Rod Holme, P.Eng., Engineering Advisor
  • Danny Hui, P.Eng., Ministry of Municipal Affairs and Housing
  • Terry Lang, C.E.T., Ontario Water Works Equipment Association
  • Tony Lotimer, M.Sc., P.Geo., Ontario Water Works Association
  • Edmond Lui, P.Eng., Safe Drinking Water Branch, MOE
  • Gord Robb, C.E.T., Ontario General Contractors Association
  • Joe Rybak, P.Eng., Ontario Clean Water Agency
  • Pervez Sunderani, P.Eng., Alberta Environment
  • Carl Vreugde, B.A., Ontario Water Works Equipment Association
  • Alex Vukosavljevic, B.A., Operators (City of Toronto)
  • Robert Walton, P.Eng., Ontario Municipal Water Association
  • Roland Welker, M. A. Sc., P.Eng., Municipal Engineers Association
  • Matt Uza, B. A. Sc., Land and Water Policy Branch, MOE

Historical Note

Since the establishment of the Ontario Water Resources Commission under the Ontario Water Resources Act (1956), the commission engineers used the Ten States Standards for Water Works as the reference design guidelines for sanitary engineering practice. These publications were prepared, edited and published, approximately every five years, by the Great Lakes Upper Mississippi River Board of State Public Health Engineers and Great Lakes Board of Public Health Engineers. The commission engineers had also developed and applied internal advisory water works design guidelines based primarily on the Ten States Standards and included design, construction and operational experience specific to Ontario.

This practice has continued after the establishment of the Ministry of the Environment in 1973. The Province of Ontario joined the Great Lakes-Upper Mississippi River Board of State and Provincial Public Health and Environmental Managers and the Ten States Standards Water Supply Committee in 1977.

Over the years, engineering design criteria based on generally accepted good engineering practice in Ontario have been developed and the following ministry guidelines were published:

  • Guidelines for the Design of Water Treatment Works (1982)
  • Guidelines for Water Distribution Systems (1979, 1985)
  • Guidelines for Water Storage Facilities (1979, 1985)
  • Guidelines for Servicing in Areas Subject to Adverse Conditions (1985)
  • Guidelines for Water Supply for Small Residential Developments (1985)
  • Guidelines for Seasonally Operated Water Supply Systems (1985)

These guidelines have been revised and updated based on Ontario-specific engineering practice, the latest Ten States Standards (Recommended Standards for Water Works, 2003) and other relevant North American design guidelines and published as the Design Guidelines for Drinking-Water Systems (2008).


The Ontario Ministry of the Environment (ministry) Design Guidelines for Drinking-Water Systems is intended for an audience that includes engineers who are responsible for designing drinking-water systems, ministry engineers responsible for reviewing and approving the designs of such systems, and the municipalities/owners of the drinking-water systems.

It is intended that this Design Guidelines document be used with professional judgment and experience in the design of drinking-water systems and in the engineering review of applications for approval of such systems. The ministry recognizes that the choice of drinking-water system designs may be influenced during the planning stages by sustainability issues, such as the cost to design and build drinking-water systems as well as the ongoing cost to operate, maintain, rehabilitate and replace infrastructure.

Designers should note that the ministry has a number of specific guidelines and/or procedures which relate to drinking-water systems that may affect design. Such specific guidelines and procedures take precedence over these Design Guidelines.

Similarly, the use of actual site-specific data is encouraged. Wherever possible, designers are encouraged to use actual data derived from the drinking-water system monitoring records and operational studies. Actual data can be compared to the typical values provided in these Design Guidelines for comparison and consideration.

As well, it should be noted that this Design Guidelines document provides design guidance related to established technologies. The fact that other technologies or equipment are not mentioned in the Design Guidelines should not be construed as precluding their use. It is not the intention of the ministry to stifle innovation. The ministry will approve drinking-water system works designs if the applicant and designer can demonstrate that the works will have a reasonable and substantial chance of success for the particular application. However, drinking-water system works designs using new and innovative technologies and equipment would be approved only where operational reliability and effectiveness of the works has been demonstrated with a suitably-sized prototype unit operating at its design load in the conditions suitable for the particular application.

Finally, it must be emphasized that this document contains design guidelines. Legislation, including legislated standards and regulations, takes precedence over the Design Guidelines and must be followed. Readers are cautioned to obtain their own legal advice and guidance in this respect.