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Middlesex-London Health Unit

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Small Drinking Water Systems

If your business or organization provides unrestricted access to drinking water for the public and your water is not directly from a municipal (city) source you could be operating a Small Drinking Water System (SDWS). These systems need to follow the requirements for Small Drinking Water Systems (O. Reg. 319/08).1


Small Drinking Water Systems can include:1

  • A food service establishment
  • A place that operates primarily for the purpose of providing overnight accommodation to the travelling public
  • A trailer park or campground
  • A marina
  • A church, mosque, synagogue, temple or other place of worship
  • A recreational camp
  • A recreational or athletic facility
  • A place, other than a private residence, where a service club or fraternal organization meets on a regular basis, or
  • Any place where the general public has access to a washroom, drinking water fountain or shower.

© Queen's Printer for Ontario, 2008

What if my business or organization operates a Small Drinking Water System?

If your business or organization operates a Small Drinking Water System you will need to review the information below:

AND contact a Public Health Inspector at:

  • 519-663-5317


Small Drinking Water Systems get assigned risk ratings: High, Moderate or Low. 

  • High risk systems are inspected / assessed every 2 years.
  • Moderate and Low risk systems are inspected / assessed every 4 years.

View the inspection results for Small Drinking Water Systems in Middlesex-London from the link below.

Inspection Results


A Church Well

A picture of a well at a church

Forms to be completed

Please return completed forms to:

  • Mail: Middlesex-London Health Unit
    Attention: Environmental Health
    355 Wellington St, Suite 110, London, ON N6A 3N7
  • Fax: 519-663-9276, or
  • E-mail:
    Please indicate "SDWS 319" in the subject line

Once the two forms have been received by the Middlesex-London Health Unit, you will be contacted by a Public Health Inspector to arrange a time for a site specific risk assessment.

Small Drinking Water Systems Operator's Guide



Adverse Water Quality Incident Reporting

If you own or operate a Small Drinking Water System you are required by law to report any adverse (bad) water quality incidents to your local health unit.

To report an adverse water quality incident (AWQI) in Middlesex-London, please call 519-663-5317. If you are calling outside of regular business hours, the answering service will direct your call to the appropriate individual.

Additional Information

To speak to a Public Health Inspector on the Environmental Health Team about Small Drinking Water Systems, or for help figuring out if you operate one, please call:

  • 519-663-5317
Date of creation: December 10, 2012
Last modified on: January 24, 2022


1Ontario. Ministry of the Attorney General. (2008). Health Protection and Promotion Act. Ontario Regulation 319/08 Small Drinking Water Systems. Retrieved from