Rules for treating industrial wastewater
The rules to establish, operate or change a wastewater treatment facility and how to monitor and report direct industrial wastewater discharges to the natural environment.
About industrial wastewater
Industrial wastewater is the by-product from an industrial process that can contain contaminants. Special care must be taken to make sure this wastewater is treated and monitored to keep harmful contaminants out of our water.
All discharges of wastewater to the natural environment are regulated under the Ontario Water Resources Act.
There are also regulations under the Environmental Protection Act covering 9 specific industrial sectors:
- electric power generation
- industrial minerals
- inorganic chemical
- iron and steel manufacturing
- metal casting
- metal mining
- organic chemical manufacturing
- pulp and paper
You can find the complete set of rules relating to these activities at:
You can also find the complete set of rules relating to effluent monitoring and limit regulations for each industrial sector at:
- Ontario Regulation 215/95 (Electric Power Generating Sector)
- Ontario Regulation 64/95 (Inorganic Chemical Sector)
- Ontario Regulation 561/94 (Industrial Minerals Sector)
- Ontario Regulation 214/95 (Iron and Steel Manufacturing Sector)
- Ontario Regulation 562/94 (Metal Casting Sector)
- Ontario Regulation 560/94 (Metal Mining Sector)
- Ontario Regulation 63/95 (Organic Chemical Manufacturing Sector)
- Ontario Regulation 537/93 (Petroleum Sector)
- Ontario Regulation 760/93 (Pulp and Paper Sector)
All industrial wastewater facilities must have an environmental compliance approval to:
- establish a new wastewater treatment facility
- use, operate, or change an existing facility
The environmental compliance approval normally imposes site-specific effluent limits and monitoring and reporting requirements for the operation of the facility.
If your facility is subject to 1 of the 9 industrial regulations, you must follow additional requirements.
Monitoring and reporting
Industrial facilities that discharge wastewater directly into Ontario’s lakes and rivers must:
- report the results to the ministry
If your facility is also regulated by 1 of the 9 industrial regulations, you must submit your results electronically using the Ministry of the Environment Wastewater System (MEWS) web application.
Sampling and analysis must be done according to the Protocol for the Sampling and Analysis of Industrial/Municipal Wastewater.