About sewage and storm water management

Sewage refers to wastewater being disposed of from various activities that may contain contaminants.

It can be:

  • sanitary sewage - everything that is flushed down the toilet or rinsed down the drain
  • wastewater - polluted water such as cooling water, wash water or process water from commercial and industrial processes
  • wash water - water that has been used to wash fruit and vegetables
  • storm water - such as rainwater and snowmelt that seep into the ground or runs off the land into storm sewers, streams and lakes

Storm water management is the practice of controlling the amount, intensity, duration and quality of rainwater and snowmelt runoff to protect the environment, mitigate flooding and erosion risk, and improve resiliency.

Sewage works

Sanitary sewage and wastewater is collected and generally moves through a series of pipes that may be aboveground or below the surface called sewers. It is typically treated through a series of physical, chemical and biological processes before effluent is discharged into the environment. Sewage that consists of storm water soaks into the ground, runs off of the land or may be conveyed through sewers and other pathways to streams and lakes with or without treatment.

The sewers, pipes and equipment used to collect, move, manage and treat sewage are collectively called sewage works. This may include storm water green infrastructure, including low impact development works, that soak storm water into the ground.

Environmental permissions for sewage works

An environmental permission is a ministry-issued approval or confirmation of registration to engage in an environmental activity. Sewage defined in the Ontario Water Resources Act, includes drainage, storm water, commercial wastes and industrial wastes and such other matter or substance as is specified by the regulations.

Under the Ontario Water Resources Act and Environmental Protection Act, you need an environmental permission to do any of the following for new or existing sewage works, including storm water management works:

  • use
  • operate
  • establish
  • alter
  • extend
  • replace

This includes the collection, transmission, treatment and discharge of storm water, wastewater, sanitary sewage, wash water and other types of sewage.

An environmental permission is required when:

  • the sewage works have a design capacity greater than 10,000 litres per day
  • more than 1 sewage works is located on a lot or parcel of land and they have, in total, a design capacity in excess of 10,000 litres per day
  • the sewage works are not located wholly within the boundaries of the lot or parcel of land on which is located the residence or other building, or facility served by the works

Sewage works discharging to surface waters require an environmental compliance approval prior to the construction of a new sewage works or for the use, operation, alterations and expansions of existing sewage works. The approval requirement also applies to any sub-surface sewage works, holding tanks or closed-loop systems if 1 or several combined sewage works have a design capacity greater than 10,000 liters per day, or if the sewage works is located on more than 1 parcel of land.

No approval required

You may not need an environmental permission in some cases. Some of the excepted circumstances listed in Ontario Water Resources Act include:

  • when performing routine maintenance
  • for sewage works from which sewage is not to drain or be discharged directly or indirectly into a ditch, drain or storm sewer or a well, lake, river, pond, spring, stream, reservoir or other water or watercourse – note does not include ground water or closed loop systems with rated capacity greater than 10,000 liters a day
  • for privately-owned sewage works designed for the partial treatment of sewage that is to drain or be discharged into a sanitary sewer (owned by a municipality)
  • for a sewage system that is subject to the Building Code Act, 1992
  • for a drainage works under the Drainage Act or a sewage works where the main purpose of the works is to drain land for the purpose of agricultural activity
  • for a drainage works under the Funeral, Burial and Cremation Services Act, 2002, the Public Transportation and Highway Improvement Act or The Railways Act, being chapter 331 of the Revised Statutes of Ontario, 1950
  • when the works are part of a renewable energy approval
  • for sewage works that is exempted by the regulations

Ontario Regulation 525/98, Approval Exemptions under the OWRA provides for exemptions. This means you may not need to obtain an environmental permission if you are:

Adding, operating, altering, replacing or extending:

Or if you are:

  • relining a sewer if the relining does not cause disruption to the operation of the sewage works
  • replacing an existing approved sewer with a like for like sewer for example, the same type and size of sewer

However, these exemptions may not apply if your works include a combined sewer that is defined in Ontario Regulation 525/98. A combined sewer conveys sanitary sewage and storm water at the same time through a single pipe.

Your storm water management works may not require an environmental permission when it meets all of the following conditions:

  • it discharges into a storm sewer that is not a combined sewer
  • it services only 1 lot or parcel of land
  • it does not service industrial land or a structure on industrial land
  • it is not located on industrial land

Industrial land means land used for the production, processing, repair, maintenance or storage of goods or materials, or the processing, storage, transfer or disposal of waste, but does not include land used primarily for the purpose of buying or selling:

  • goods or materials (such as those for commercial use) other than fuel, this means a gas station is industrial land, or
  • services other than vehicle repair services, this means a vehicle repair business such as a repair shop or garage is industrial land

Some examples, of sewers and storm water management works that may not require an environmental permission include:

  • you have a sewer or storm water works on your residential lot that discharges to a municipal sewer
  • you have storm water management works that collect and treat storm water captured only from your non-industrial lot that means, storm water does not flow onto your property and is not captured by your works

Storm water green infrastructure and low impact development

The use of storm water green infrastructure, including low impact development works is an approach to storm water management that seeks to manage rain where it falls and snow melts, to reduce runoff and storm water pollution. Some examples of low impact development practices include rain gardens, urban trees, permeable pavements, green roofs, and rainwater harvesting. They can be established on private properties, public properties and public/road rights of way.

Your storm water green infrastructure (low impact development works) may not require an environmental permission if it is located on one lot or parcel of land where people live that is, used for a residential purpose and all buildings are residential.

You may not require an environmental permission if any of the following apply to you:

  • the sole purpose of your sewage works is to collect, transmit, treat and dispose of ground water and storm water taken from the foundation of a building, such as a foundation drain
  • for any part of a sewage works that is used to control quagga and zebra mussels with ultraviolet light provided no chemicals are used
  • the sole purpose of your sewage works is to collect, transmit, treat and dispose of ground water and storm water to create or maintain a dewatered (dry) area at a construction site for a construction project however, you may need a permission for water taking
  • if your sewage works are part of a large municipal residential system or a small municipal residential system that is defined in Ontario Regulation 170/03 Drinking Water Systems under the Safe Drinking Water Act, 2002
  • for a vegetated filter strip as defined in Ontario Regulation 267/03 General under the Nutrient Management Act, 2002, that manages runoff as part of an agricultural operation
  • if you are managing greenhouse nutrient feedwater that is generated at a greenhouse that is registered under Ontario Regulation 300/14 Greenhouse Nutrient Feedwater under the Nutrient Management Act, 2002

Learn more about exceptions in section 53(6) of the Ontario Water Resources Act.

Learn more about exemptions in Ontario Regulation 525/98, Approval Exemptions.

In summary, you may require an environmental permission when all of the following apply:

  • you are collecting or treating sewage that meets the definition in the OWRA
  • you are capturing sewage in a sewage works that meets the definition in the OWRA
  • you plan to establish, use, operate a sewage works or alter extend or replace an existing sewage works
  • none of the exceptions or exemptions apply to you

It is your responsibility to be aware of and understand all legal requirements that apply to your activity. You can contact us if you need more information about exceptions and exemptions.

Types of environmental permissions

Environmental permissions for sewage include:

  • Environmental Compliance Approvals (ECA)
  • Environmental Activity and Sector Registry (EASR) for storm water management works

Most sanitary and industrial sewage works require an ECA, you may be required to submit an application to the ministry for approval.

See Environmental Compliance Approval for more information.

Certain storm water management works are subject to registration, see Environmental Activity and Sector Registry for more information.

See Ontario Regulation 137/25: Registrations Under Part II.2 of the Act - Storm Water Management Works to determine whether your storm water management works are subject to registration.

Learn more about storm water management works guidance for the Environmental Activity and Sector Registry to self-register your works in the EASR.

Municipal Consolidated Linear Infrastructure ECA

A Municipal Consolidated Linear Infrastructure (CLI) ECA is a single environmental permission for all the sewage works components of a municipal sewage collection system or a municipal storm water management system. Municipal sewage systems are residential sewage works that collect and transmit sanitary sewage and municipal storm water management systems generally include residential and commercial storm water management works. Both are owned by a municipality and within their geographical boundaries.

CLI ECAs are issued to municipalities. They include conditions that authorize these municipalities and prescribed persons for example, developers, to make changes to the system when requirements in the CLI ECA are met.

Learn more about Municipal Consolidated Linear Infrastructure Environmental Compliance Approvals.

Commercial and institutional sewage works that are non-municipal

Commercial and institutional sewage works that are not owned by a municipality, also called private sewage works, typically exist where municipal sewage systems are not available. These sewage works may service privately owned residential developments that will not be assumed by a municipality for example, seasonal communal works or commercial properties, golf courses or institutional facilities such as health care facilities.

Commercial and institutional sewage works may treat sanitary sewage, process water, cooling water, wash water or storm water or a mixture of all. Prior to construction, an Environmental Compliance Approval is required to use, operate, establish, alter, extend or replace new or existing sewage works including storm water management works in accordance with the Ontario Water Resources Act.

Agricultural wash water and water with added nutrients

Some agricultural operations require an Environmental Compliance Approval for the following activities:

  • collection, transmission, treatment and discharge of storm water
  • land application of treated effluent from any on-farm or off-farm wastewater source (excluding nutrient feedwater that is generated at a greenhouse that is registered under O. Reg. 300/14 under the Nutrient Management Act)
  • collection, transmission, treatment and discharge of process wastewater such as, vegetable washing wastewater, water with added nutrients, and recycled water
  • larger subsurface (septic) systems with a design capacity of more than 10 000 litres per day, 1 or more on same property, or crosses property boundaries (as set out in Section 6.1 of the Ontario Water Resources Act)

Clean water is used by the agricultural sector to wash agricultural products in Ontario but the vegetable wastewater resulting from washing is captured under the broad definition of sewage under the Ontario Water Resources Act. Get more information in the guide to obtaining approval for a greenhouse storm water management facility (PDF).

Large subsurface disposal systems

Large subsurface disposal systems are frequently used as part of an on-site sewage works or communal sewage works to treat sewage and discharge below ground.

An ECA is required for on-site sewage works that meet at least one of the following criteria:

  • your sewage works have a design flow greater than 10,000 litres per day
  • more than one sewage works is located on a lot or parcel of land and in total, the design flow is more than 10,000 litres per day
  • the sewage works are not wholly located on the lot or parcel of land on which the residence, building or facility that they are servicing is located regardless of design flow

Learn more about large subsurface disposal systems.

Industrial sewage

Industrial sewage works are any works involving the collection, transmission, treatment or disposal of sewage generated from industrial activities or located on industrial land. This could include projects to manage storm water runoff, sanitary sewage and process sewage from properties with industrial activities or sewage from site remediation activities at industrial sites.

Learn more about the requirements for applying for an ECA for sewage works in:

Learn more about Environmental Compliance Approvals.

Financial assurance

In areas without a municipality, the ministry may include a financial assurance condition in an ECA for private communal sewage works since there is no local government agency to take over the works in the event of a default. If a default happens, the financial assurance held by the ministry would be used to either decommission the works or pay for the works to be operated on an interim basis until another operator can take on the system.

For more information about financial assurance, when it applies and how to calculate it, refer to the financial assurance for environmental protection and financial assurance guideline.

Presubmission meeting with the ministry

Presubmission consultation meetings with ministry staff provide an opportunity for us to discuss and clarify complex technical requirements. These meetings can help you define the environmental design objectives for your sewage works, identify any special circumstances and approval-related requirements.

You can request a presubmission consultation meeting with the ministry by contacting an Environmental Compliance Officer (ECO) at your local district office. An ECO will review your request for a meeting and gather the right ministry people to discuss your ECA application.

See the district locator tool to find your local district office.

Contact us

For more information you can contact the Client Services and Permissions Branch at: