York Region Sewage Works Project

Supporting Growth and Housing in York and Durham Regions Act, 2022 

On November 28, 2022, the Ontario government passed the Supporting Growth and Housing in York and Durham Regions Act, 2022.

The Act mandated York Region change from the previously proposed Lake Simcoe watershed solution, also known as Upper York Sewage Solutions, to a Lake Ontario solution that will direct, transport and treat wastewater at the Duffin Creek Water Pollution Control Plant in Durham Region.  

The Act required:

• York Region and Durham Region prepare:
  • A Project Report to identify infrastructure components, required work, required approvals, costing, potential impacts to the environment and related mitigation
  • Two Consultation Reports - one outlining consultation with Indigenous communities and the other outlining consultation with the public.
• All reports be submitted to the Minister of the Environment, Conservation and Parks and completed to the Minister’s satisfaction

Project and Consultation Reports were shared for public review on November 6, 2023 and submitted to the Minister of the Environment, Conservation and Parks on March 15, 2024.

On April 22, 2024, the Minister of the Environment, Conservation and Parks confirmed York Region and Durham Region satisfied conditions of the Act and can proceed with implementing the project.

Infrastructure components in the Project Report are exempt from the Environmental Assessment Act because the Province established a separate planning and review process for this Project under the new Act.

York Region and Durham Region submitted the York Region Sewage Works Project Report outlining infrastructure components and costs, impacts to the environment and how those impacts will be mitigated to the Minister of the Environment, Conservation and Parks, in accordance with the Act. 

• Cover Page and Table of Contents
• Chapter 1 Introduction and Background
• Chapter 2 Confirmation and Description of Components
• Chapter 3 Design Basis
• Chapter 4 Infrastructure Located in East Gwillimbury
• Chapter 5 Infrastructure Located in Newmarket and Aurora
• Chapter 6 Leslie Street Trunk Sewer and Yonge Street Sewer Rehabilitation
• Chapter 7 Markham Collector Twinning
• Chapter 8 Primary Trunk Twinning
• Chapter 9 Duffin Creek Water Pollution Control Plant Expansion and Upgrades
• Chapter 10 Duffin Creek Water Pollution Control Plant New Outfall
• Chapter 11 Implementation Plan
• Chapter 12 Conclusion
• Appendix A Chapter 4 Drawings
• Appendix B Chapter 5 Drawings
• Appendix C Chapter 6 Drawings, CI-D019 – CI-D021
• Appendix C Chapter 6 Drawings, CI-D022 – CI-D024
• Appendix D Chapter 7 Drawings
• Appendix E Chapter 8 Drawings

• The existing York Durham Sewage System (YDSS) was constructed by the Ontario government in the early 1980s to service communities in York Region and Durham Region and as the populations grows, the system needs to be expanded to provide additional servicing capacity to accommodate growth
• Communities in York Region and Durham Region that rely on the YDSS are expected to continue growing; the Regions anticipate that by 2051, the number of current residents will double from those in 2021
• Residents and businesses rely on the Regions and their local cities and towns to provide critical services like wastewater collection and treatment
• On November 28, 2022, the Ontario government passed the Supporting Growth and Housing in York and Durham Regions Act, 2022
• The Act mandated that the previously proposed wastewater treatment solution based in the Lake Simcoe watershed to support growth in northern towns in York Region, also known as Upper York Sewage Solutions, be changed to a Lake Ontario solution directing, transporting and treating wastewater at the Duffin Creek Water Pollution Control Plant on the shore of Lake Ontario in the City of Pickering in Durham Region
• The Act requires both Regions to expand and improve the existing YDSS in York Region and Durham Region to move wastewater resulting from growth identified in the 2022 York Region Water and Wastewater Master Plan and Amendment
• By expanding the existing system, future population growth can be serviced efficiently, making the best use of the existing wastewater infrastructure
• Delivering critical YDSS infrastructure will unlock servicing capacity required to build more homes in support of the provincial priority for increased housing

• The Act required York Region and Durham Region to prepare:
  • A Project Report to identify infrastructure components, required work, required approvals, costing, potential impacts to the environment and related mitigation
  • Two Consultation Reports - one outlining consultation with Indigenous communities and the other outlining consultation with the public
  • All reports were to be submitted to the Minister of the Environment, Conservation and Parks and be completed to the Minister’s satisfaction
• The Project and Consultation Reports were shared for public review on November 6, 2023, and then submitted to the Minister of the Environment, Conservation and Parks on March 15, 2024
• On April 22, 2024, the Minister of the Environment, Conservation and Parks confirmed York Region and Durham Region satisfied the conditions of the Act and can proceed with implementing the project

The Project is made up of 28 individual Project components in the following three geographic areas: 

• York Durham Sewage System (YDSS) North Expansion
• YDSS South Expansion
• YDSS Primary System Expansion 

Project components will be delivered to accommodate forecasted growth to 2031, 2041 and 2051.

York Region

• Town of East Gwillimbury – New sewers, modifications to existing sewers, new pumping stations and upgrades to existing pumping stations
• Town of Newmarket – New sewers and pumping stations and modifications to existing pumping stations
• Town of Aurora – New sewers and pumping stations and modifications to existing pumping stations
• City of Richmond Hill – New sewers and rehabilitation of existing sewers
• City of Markham – New sewer

Durham Region

• City of Pickering and Town of Ajax – New sewers and pumping stations and upgrades to Duffin Creek Water Pollution Control Plant, including a new outfall

The majority of proposed infrastructure will be constructed within existing corridors, which will minimize potential impacts on sensitive natural areas.

• The York Region Sewage Works Project Report was developed in consultation with Indigenous communities, local municipalities, agencies and the public
• The Project Report was one part of engagement because York Region and Durham Region will continue to engage with Indigenous Communities local municipalities, agencies and the public during detailed design and construction
• York Region and Durham Region are committed to early and ongoing respectful dialogue with Indigenous communities on matters of the Project that affect or may affect constitutionally protected Aboriginal and treaty rights

• Impacts to surrounding communities and travelling public will depend on the type of infrastructure being built and their proximity to the construction works
• As with all construction, York Region and Durham Region use industry best practices to manage construction hours, equipment, noise, dust and traffic
• Residents and businesses surrounding construction areas will receive regular construction updates and notices

The overall project is expected to be completed by 2041, with individual components following different delivery timelines. For the most up-to-date information, please refer to the Latest News section at the bottom of this page.

Most wastewater from homes and businesses in York Region moves through a network of sewers and sewage pumping stations called the York Durham Sewage System. Wastewater travels through local small-diameter sewer pipes owned and maintained by York Region’s nine cities and towns. These pipes connect into a large-diameter sewer system known as the York Durham Sewage System that currently conveys about 85% of the Region’s wastewater for treatment at the Duffin Creek Water Pollution Control Plant in the City of Pickering on the shore of Lake Ontario. 

The Duffin Creek Water Pollution Control Plant has an underground outfall pipe that extends more than one kilometre under the lake bed into the deeper waters of Lake Ontario. At the end of the outfall pipe, nozzles extend above the lake bed and release treated, clear and disinfected water into Lake Ontario. 

The Duffin Creek Water Pollution Control Plant is the most highly regulated treatment plant discharging to the open waters of Lake Ontario. Among its benefits, it has the strictest phosphorus concentration compliance limits of all large treatment plants in the GTA.

There are two main types of large-diameter trunk sewer pipes used in York Region:

• Gravity sewers – these pipes are built with a downward slope so that gravity can be used to move the wastewater from one point to another
• Forcemain sewers – a type of sewer that moves wastewater using pressure created by pumps
• Trunk Sewer and Collector Sewers – these sewers are larger in diameter and carry more wastewater than other gravity sewers and sewage forcemains
• Interceptor Sewer – a sewer constructed to redirect flow from an existing sewer to a new sewer

York Region funds its capital projects through a combination of sources, including federal and provincial grants, regional development charges, property taxes and other funding programs. Budgeting for capital projects is included in the Region’s 10-year Capital Plan.