This technical bulletin is one in a series of 11 on well issues created for a person who currently owns a water supply well. The purpose of this technical bulletin is to summarize the information on when to abandon a well found in the Water Supply Wells – Requirements and Best Management Practices manual published by the Ministry of the Environment and Climate Change. If a well is required to be abandoned, well owners should refer to Regulation 903 (Wells Regulation), as amended, made under the Ontario Water Resources Act and the Wells Regulation – Well Abandonment: How to Plug and Seal a Well technical bulletin.

Problems Associated with Improperly Abandoned Wells

Improperly abandoned wells may pose any of the following problems:

  • Pose a threat to children, adults or animals that may fall into large diameter openings and become trapped or injured.
  • Present a hazard to farm machinery and vehicles.
  • Act as pathways for the movement of contaminants such as bacteria, pesticides, fertilizers, into groundwater supplies.
  • Interconnect groundwater zones allowing salty or mineralized water to enter fresh water zones.
  • Flow uncontrollably at the surface resulting in groundwater waste, nuisance, property damage or flooding problems.

Examples of improperly abandoned wells include: wells left unused, wells that are not maintained, forgotten wells, or wells that were plugged and sealed using sub-standard methods.

To reduce the risk of improperly abandoned wells, the Wells Regulation outlines requirements as to when and how to abandon a well. By eliminating both the physical hazards and contamination pathways, well owners are protecting the water quality of existing and future wells and the shared groundwater resources. By taking these precautions, well owners are reducing potential financial liabilities while making a wise investment in the future.

When to Abandon a Well

Person Constructing the Well

If construction is discontinued before the well is completed, the person constructing the well must immediately abandon the well.

Well Purchaser

The well purchaser (a person who enters into a contract with a licensed well contractor) of a new well that is dry must immediately abandon the well, unless the owner of the land on which the well is situated agrees in writing to maintain the well for future use as a well.

Well Owner

The well owner must immediately abandon a well if it:

  • is not being used or maintained for future use as a well
  • produces mineralized water
  • produces water that is not potable unless the well owner seeks the advice of, and follows the directions of, the local medical officer of health
  • contains natural gas or other gas unless measures are taken to manage the gas in a way that prevents any potential hazard
  • permits any movement of natural gas, contaminants or other materials between subsurface formations (e.g. aquifers), or between a subsurface formation and the ground surface, and the movement may impair the quality of any waters unless measures are taken that prevent the movement at all times
  • is constructed in contravention of any provision of the Wells Regulation dealing with the location of wells, the methods and materials used in the construction of wells or the standards of well construction, and any steps taken to immediately rectify the situation have failed.

In some circumstances, written consent not to abandon a well may be issued by the Director under the Act. See the Process to Seek Director’s Written Consent not to Abandon a Well section on the next page, for further information.

Remedial Measures

If the well owner takes measures to prevent movement of contaminants or other substances, or takes measures to rectify a well producing water that is not potable, contains natural gas or other gas, the Wells Regulation requires the well owner to make sure the measures are functional at all times.

Exemption from Well Abandonment Requirements for Water that is Mineralized or Not Potable

The well owner does not need to abandon the well if the well water is mineralized or not potable under the following scenario:

  • the well is used or intended for use as a source of water for agriculture (such as watering livestock or irrigating crops)
  • the well is not used as a source of water for human consumption (see below for further information on exemptions).

Seeking Advice from the Local Medical Officer of Health where Well Water is Not Potable

“Potable” means water that meets the Ontario Drinking Water Quality Standards found in Regulation 169/03, as amended, made under the Safe Drinking Water Act, 2002. This regulation can be found at the Ontario e-Laws website.

When a well produces well water that is not potable (i.e. does not meet one or more of the Ontario Drinking Water Quality Standards), the well owner may seek the advice of and take such measures directed by the local medical officer of health as an alternative to immediately abandoning the well.

To determine which local Public Health Unit in Ontario has authority for the area, the well owner can do any of the following:

Process to Seek Director’s Written Consent not to Abandon a Well

The well owner is not required to abandon a well if the owner has sought and obtained the written consent of the Director under the Act to allow for the continued use of the well. The following situations require written consent from the Director under the Act, if the well owner wants to continue using the well:

  • A well produces mineralized water
  • A well produces water that is not potable and the well owner does not immediately seek advice from the local medical officer of health or does not follow the directions of the local medical officer of health
  • A well contains natural gas or other gas and measures have not been taken to manage the gas to prevent any potential hazard
  • A well permits any movement of natural gas, contaminants or other materials between subsurface formations, or between a subsurface formation and the ground surface, and the movement may impair the quality of any waters and measures have not been taken to prevent the movement
  • A well is constructed in contravention of any provision of the Wells Regulation dealing with the:
    • location of wells
    • methods and materials used in the construction of wells
    • standards of well construction
    • the well owner has not taken immediate steps to rectify the situation or the steps taken have failed.

Well owners and others should be cautioned that obtaining a written consent from the Director under the Act will not be a simple and automatic process. The Director under the Act needs to consider the conservation, protection and management of Ontario’s waters.

Information on how the Director’s written consent process works can be found in Chapter 14: Well Abandonment: When to Plug & Seal Wells of the Water Supply Wells – Requirements and Best Management Practices manual.

If a well owner wishes to seek the written consent of the Director under the Act, the well owner may contact the Wells Help Desk:

  • In writing to the Director under the Act c/o Wells Help Desk, Environmental Monitoring and Reporting Branch of the Ministry of the Environment, 125 Resources Road, Etobicoke ON M9P 3V6
  • Tel: 1-888-396-WELL (9355) (for Ontario residents only)
  • Fax: 416-235-5960
  • By e-mail at helpdesk@waterwellontario.ca

Test Holes and Dewatering Wells

New test holes and dewatering wells, as defined by the Wells Regulation, have other well abandonment requirements and exemptions. For further information on the construction and abandonment requirements for test holes and dewatering wells, see the Wells Regulation.

Additional Information Sources

This technical bulletin on well issues is one in a series of 11 created for owners of water supply wells which are available on the Water Supply wells: technical bulletin page.

Further information on well abandonment can be found in Chapter 14: Well Abandonment: When to Plug & Seal Wells and Chapter 15: Abandonment: How to Plug & Seal Wells of the Water Supply Wells – Requirements and Best Management Practices manual.

A copy of the Water Supply Wells – Requirements and Best Management Practices manual can be obtained from the ministry’s website.

A copy of Regulation 903 (Wells Regulation), as amended, made under the Ontario Water Resources Act and other regulations can be obtained from the Ontario e-Laws website.

The publications are also available by calling the Publications Information Centre at 1-800-565-4923 or 416-325-4000.

For further information about wells, contact the Wells Help Desk at 1-888-396-WELL (9355) or the nearest Ministry of the Environment and Climate Change office listed in the blue pages of the telephone directory.

Notice: This bulletin is being provided for information purposes only and is not intended, nor should it be construed as providing legal advice in any circumstances. The applicable legislation including the Ontario Water Resources Act and Regulation 903, as amended and made under that Act, should be consulted. Legislation and regulations change from time to time so it is essential that the most current versions be used.

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