Municipalities are responsible for drinking water systems in Ontario

Municipalities are responsible for building, operating and maintaining Drinking Water Systems in Ontario and testing for water quality. Over 80% of Ontarians receive their drinking water from municipal residential drinking water systems.

The provincial government’s Ministry of the Environment, Conservation and Parks (MECP) regulates municipal Drinking Water Systems and provides oversight of these systems to ensure water safety and quality.

Ontario’s Drinking Water Quality Standards (O. Reg. 169/03) under the Safe Drinking Water Act, 2002 outlines the standards for 151 microbiological, chemical, and radiological parameters based on Health Canada’s Drinking Water Quality Guidelines, including:

• Chemical testing
  • Trihalomethane
  • Haloacetic Acids
  • Nitrate and Nitrite
  • Sodium
• Lead testing
  • Lead – Plumbing
  • Lead – Distribution
  • Alkalinity – Distribution
  • pH – Distribution
• Inorganic testing
  • Arsenic
  • Cadmium
  • Mercury
  • Uranium
• Organic testing
  • Benzene
  • Polychlorinated Biphenyls (PCB)

In 2024, 99.9% of the over 524,000 tests conducted for these parameters were within the limits set in the standards. Municipalities must report their results annually.

The Minister publishes an annual report on drinking water testing:

• 2024
• 2023
• 2022
• 2021
• 2020
• 2019
• 2018
• 2017

Non-municipal drinking water lacks oversight and support, posing a public health risk: Auditor General

Almost 3 million Ontario residents (almost 20% of the population), as well as many businesses and other facilities, rely on non-municipal drinking-water supplies for drinking, preparing food, and bathing.

98%+ of all samples taken from non-municipal drinking water systems over the past 10 years have met Ontario’s standards, however, a 2025 audit by the Auditor General of Ontario found that some public non-municipal drink water systems have not been identified, assessed or inspected by Public Health Units:

• Some small drinking-water systems have not been identified, assessed and inspected by Public Health Units (PHUs) overseen by MOH, posing a public health risk. These types of non-municipal systems serve six or more seasonal residences or a public facility, such as a hotel, restaurant or church.
• 17 (52%) of the 33 Public Health Units with small drinking water systems in their region did not inspect all systems as required.
• 56% of 1,660 small drinking water systems missed at least one sample in the past 5 years
• Public health units issued fines to the owners of 1% of the 932 non-compliant systems in the past 5 years.
• Ministry of Health is not tracking progress toward outcomes for its drinking water program, so it is unaware if all public health units are holding owners accountable.
• 4 of 26 public health units informed private well owners about potential chemicals in their water.

Performance Audit: Safety of Non-Municipal Drinking Water – Auditor General of Ontario

For example:

• Kendra Hodgson of Bay Ridge Apartments residential complex in Belleville, Ontario fined $10,000 for Safe Drinking Water Act Violations
• Alliston Interdenominational Christian School Society fined $9,500 for failing to meet sampling/testing requirements

Small drinking water systems are the responsibility of the owner

Small Drinking Water Systems (SDWS) are operated by businesses or organizations that do not get their drinking water from a municipal drinking water system. Over 80% of SDWS use groundwater as their water source.

Small systems regulated by Ministry of Health

Are governed by O. Reg 319/08 (Small Drinking Water Systems) under Ontario’s Health Protection and Promotion Act. Owners are legally required to provide users with safe drinking water at all times.

They can include:

• Small Non-Municipal Non-Residential
  • Place of worship
  • Hotel
  • Motel
  • B&B
  • Restaurant
• Large Non-Municipal Non-Residential
  • Resort
• Small Municipal Non-Residential
  • Community hall
  • Sports field/arena
• Large Municipal Non-Residential
  • Municipally-owned airport
  • Large sports and recreation facilities
  • Industrial park
• Non-Municipal Seasonal Residential
  • Trailer park
  • Campground
  • Private cottages with communal drinking water systems
• Gas stations
• Libraries
• Marinas
• Other facilities that provide the general public with access to a washroom, drinking water fountain, shower or outdoor tap

The Ministry of Health provides oversight of these systems to ensure water safety and quality. Local public health inspectors represent the ministry at the municipal level and conduct individual site-specific risk assessments then issue a directive, setting out individual requirements for each system and publish Drinking Water Advisories:

Small systems regulated by MECP

Designated facilities that provide drinking water to people who may be more at risk to illness must follow special requirements are governed by O. Reg 170/03 (Drinking Water Systems) of the Safe Drinking Water Act:

• Child care centres
• Schools, private schools, universities and colleges
• Health care facilities
• Children and youth care facilities
• Children’s camps
• Delivery agent care facilities such as emergency shelters
• Senior’s facilities
• Social care facilities
• Emergency shelters or long-term housing funded under the Homeless Prevention Program

Private wells (groundwater) and intakes (surface water) are the responsibility of the owner

Private wells and intakes that serve 5 or fewer homes are the least regulated drinking water supply and have no testing requirements. Water quality is the owner’s responsibility. You can see if there is a well on a property using the map of wells in Ontario.

About 1.3 million Ontarians rely on private wells for drinking water, but less than 33% tested their water within the last year.

Public Health Ontario provides free private well water testing for the level of bacterial organisms E. coli and total coliforms, but does not test for other contaminants such as chemicals. You can get a well water sample kit available from Public Health Ontario or your local public health unit.

To test for chemicals or other contaminants, contact a licensed laboratory.

You can determine if your water supply is suitable for potable use (there is no significant evidence of bacterial contamination) by submitting well water samples to Public Health Ontario or to your local public health unit.

Well water quality is not constant and can change over time. Testing frequently, together with inspecting and maintaining the well, will help ensure the quality of your drinking water.

Federal contaminated sites may be nearby

Canada’s Federal Contaminated Sites Inventory identifies sites under federal custodianship or that the Government of Canada has accepted some financial responsibility for, that are known or suspected to be contaminated, which means:

one at which substances occur at concentrations that:

(1) are above background levels and pose, or are likely to pose, an immediate or long-term hazard to human health or the environment; or

(2) exceed the levels specified in policies and regulations. A real property may have more than one contaminated site.

Treasury Board of Canada Secretariat