Backflow Prevention Program logo

The Town of Aurora will be implementing a mandatory Backflow Prevention Program, under Backflow and Cross Connection By-law 6213-19. To comply with the Bylaw, all industrial, commercial and institutional, and multi-residential property owners have to install a backflow preventer on the water supply line to their property. Multi-residential properties are those that have more than six units sharing a single water service.

The purpose of the Program is to ensure that the Town continues to provide safe and high-quality drinking water to our community by decreasing the chance of backflow.

Backflow happens when water from private properties flows back into the municipal water distribution system. These properties may have internal connections (called cross connections) to water used for non-potable purposes. This can create unsafe situations because of the potential for contaminants to flow back into the drinking water system.

Customers will receive information about the program by mail followed by Notices to Comply with the Backflow and Cross Connection Bylaw.

The bylaw will require industrial, commercial, institutional, and multi-residential property owners to undertake the following at their properties: 

Conduct a survey
  • The property owner will receive a Notice to Comply when a Cross-Connection Control Survey is required at the property.
  • Select a qualified contractor.

  • Have the selected contractor survey the property to identify potential or existing cross connections within the plumbing.

  • As part of the survey, have the contractor classify the degree of hazard of your property.

  • Submit the completed Cross-Connection Control Survey to the Town.

  • Conduct a survey of the property every 5 years thereafter or whenever there is a change in use or ownership of the property

Install and/or test the backflow prevention device
  • The property owner will receive a Notice to Comply as a reminder if a backflow preventer(s) needs to be installed based on the survey report.
  • If the property does not have a backflow device, have the selected contractor install the required device and test it.

  • If the property already has the appropriate backflow preventer, have the selected contractor test the backflow prevention device.

  • Testing of the device is required at installation, after repair or relocation, and yearly thereafter.

  • The contractor must attach a test tag to the device.

  • The property owner must submit the Cross-Connection Control Test Report to the Town.

  • Owners must maintain the devices and address any corrective actions identified in the Cross-Connection Control Survey or Cross Connection Control Test Report.

  • Keep copies of the reports on-site

  • Notify the Town of any change to a property use (due to operational or tenant changes)

It is the responsibility of the selected contractor to determine the degree of hazard and type of device to be installed. These must be done according to the Canadian Standard Association  - CSA B64.

The program will be rolled out in three (3) phases:

  • Phase 1 – Properties classified as a severe hazard

  • Phase 2 – Properties classified as a moderate hazard

  • Phase 3 – Properties classified as a minor hazard. Devices would not be required at these properties unless the property use and hazard level changes.

Learn more:

How Does Aurora's Drinking Water System Work?

The Town of Aurora distributes clean, safe drinking water through the local distribution system to individual customers.

York Region supplies treated drinking water to the Town. The drinking water supplied by the Region is a blend of water sourced from Lake Ontario and ground water wells.

Aurora's Water System

Under certain rare conditions, water from a private property could flow back into the Town’s drinking water system, creating an unsafe situation. Here’s how:


  • Backflow happens when the normal flow of water reverses. Backflow may occur if there is a large pressure difference between the drinking water system and the customer's private system. This could happen if there is a break in a watermain, during use of a hydrant, or if pumps on private property increase pressure at the site. 

  • Cross connections is a connection between the drinking water pipes to another water source or to a source of contamination, like process water.

Before Backflow Prevention

After Backflow Prevention

Backflow Prevention By-Law
The Town of Aurora is taking steps to ensure that our drinking water continues to be clean and safe. 

The Town is legally responsible under the Safe Drinking Water Act, Section 19, Standard of Care to do its due diligence. Installation of backflow preventers is required under Section 7 of the Ontario Building Code and is considered to be industry best practice. 

Property types

To comply with the Bylaw, Industrial, Commercial and Institutional and multi residential property owners will be required to:

  • Conduct a cross connection survey of the private water plumbing and send the Town the Cross Connection Control Survey by fall 2019 and every five years after that.
  • Install backflow prevention devices at each property by 2020.
  • Test backflow prevention devices and send the Town the Cross Connection Control Test Report annually beginning in Spring 2020.
Residential property owners will not be impacted by this bylaw at this time.  However, a residential property may be subject to the bylaw if it poses a high risk for contaminating the water supply.


 Frequently Asked Questions
Is this program related to basement flooding and installation of backwater valves on sewer lines?
No. The Town’s Backflow Prevention Program deals with protecting our drinking water. This program is not to be confused with backwater valves that are placed on sewer lines to prevent basement flooding.
Why is a Backflow Prevention Program (BFPP) Needed?
The Town's Backflow Prevention program is developed under bylaw 5645-14 to protect the health and prevent possible drinking water contamination from unprotected Cross Connections. The program is necessary to meet the requirement of the Safe Drinking Water Act, 2002, the Ontario Building Code (OBC) and the Canadian Standards Association (CSA) B64. The BFPP and Bylaw are aligned with the Town's Drinking Water Quality Management System to provide safe drinking water to its residents and businesses.
What is a Cross-Connection?
A Cross-connection is any temporary or permanent connection between a municipal drinking water system and any source or system containing non-potable water or other pollutants. Examples of cross connections are the connection between a public water system and a heating/ cooling system, or a fire system, or an irrigation system, etc.

Cross connections pose a hazard to the drinking water system if backflow occurs and contaminated water from a building is drawn back into the drinking water system.

A connection is any temporary or permanent connection between a municipal drinking water system and any source or system containing non-potable water or other pollutants. Examples of cross connections are the connection between a public water system and a heating/ cooling system, or a fire system, or an irrigation system, etc.

Cross connections pose a hazard to the drinking water system if backflow occurs and contaminated water from a building is drawn back into the drinking water system.

What is Backflow?
Backflow is defined as the undesired reversal of drinking water flow within a plumbing system. When flow reversal occurs, there is a potential to draw water and potentially pollutants into the drinking water piping and ultimately the Town’s drinking water distribution system. This results in unsafe conditions at the property, Town’s drinking water system and neighbouring properties.
What Causes Backflow?

Backflow can happen because of backpressure or back siphonage.

Backpressure: Occurs when the pressure within a building’s plumbing system is greater than the pressure in the drinking water system. This results in the water within that building being forced backward and into the Town’s drinking water system. These situations can occur at high rise buildings as a result of increasing pressures to pump water to the upper floors or at industrial buildings from pumps within the processes.

Back Siphonage: Occurs when the pressure in the drinking water system is decreased due to a watermain break, hydrant flushing operations or firefighting operations.

How often does backflow and contamination of the drinking water system happen?
The opportunity for backflow occurs whenever there is a large difference in pressure between the private system and the Town's drinking water system. The occurrence of major pollutants entering the drinking water system is less frequent but can happen at any time when there is backpressure or back siphonage and no backflow prevention device is installed. 
What properties does the Backflow Prevention Program apply to?
This program applies to existing and new industrial, commercial, institutional, as well as mixed-use and multi-residential buildings. It also applies to any property that poses a risk to the quality of the Town's drinking water and safety of our community, regardless of property class.
How does this program apply to Townhouses?
This program does not apply to townhouses where there are individual water services to each townhouse from the Town’s drinking water system. However, in cases where there is a single water service line from the Town’s drinking water system for the entire subdivision, backflow prevention will be required.
Would any buildings be exempt or grand-parented under the program?
There will be no exemptions or grand-parenting.
What is the definition of a Multi-Residential Building? 
A “multi-residential building" means a residential building that consists of more than six (6) self- contained residential dwelling units, but does not include buildings that only consist of residential single- dwelling units that are solely attached to other residential units on the sidewall (such as semi-detached homes, townhomes or row houses) or single-dwellings that contain basement apartments or annexes.
Who is responsible for meeting he BFPP requirements?

The owner of the property or agent of the owner.

What are my responsibilities to comply with the Backflow prevention bylaw?

The owner of the property or agent of the owner must ensure that the following activities are performed, and reports submitted to the Town within the timelines indicated in the by-law:

  • Undertake a Cross Connection Control Survey for each service connection at every property you are responsible for and submit the signed Survey Report to the Town. These are required every 5 years or when there is a change in ownership or property use.
  • Obtain a permit and install Backflow Preventer on each service connection.
  • Test Backflow Preventer(s) upon installation, repair, relocation or replacement and annually thereafter, and submit the signed Test Report(s) to the Town.
  • Undertake corrective actions identified in Cross Connection Control Survey Report and/or the Backflow Prevention Device Test Report
  • Ensure that the work is performed by qualified personnel as required under the by-law. Owners will be responsible for all costs related to backflow prevention at their properties.
Will there be Administration Fees?
No, the Town will not charge administration fees for this program. 
Will there be one submission date for everyone?
There is a deadline of spring 2020 for everyone, for the initial Cross Connection Control Surveys. However owners can choose to submit them earlier which will determine the 5-year anniversary date for submission of future surveys. The recommendations from the surveys will determine if a device is required. The device installation date would be the anniversary date when the test report would be due.
What are the consequences of not complying with the requirements of the Backflow prevention program?
Compliance will be monitored by the Town’s Operational Services. Enforcement will range from reminders and notifications to fines, penalties and disconnection of the water supply to the subject property.
What is a Backflow Preventer?
A Backflow Preventer is a mechanical device that prevents the backflow of water into the public drinking water system. The type of device required for your facility is based on the hazard level your facility is classified as. The types of Backflow Preventers used for premise isolation are:  Reduced-Pressure Principle Assembly and Double Check Valve Assembly.
What is Premise Isolation?
Premise isolation is the separation of Town’s drinking water distribution system from the private plumbing system through the installation of a testable backflow prevention device downstream of the water meter. 
Where should I install the Backflow Preventer?
Backflow preventers are typically installed on the water service connection, on the private side, immediately downstream of the water meter and upstream of any connections. This location must meet the requirements of the Ontario Building Code (OBC). A building permit must be obtained from the Town’s Building Services prior to installation. If you have a unique situation where the location of the backflow preventer may not meet the requirements of the OBC, we encourage you to contact Water Services to discuss your situation.
Will the water pressure be reduced within the private plumbing due to the installation of a premise isolation backflow preventer?
Yes. The installation of a backflow preventer will reduce the water pressure within your facility. Please consult with the contractor to ensure that there will be adequate water pressure for your processes after the backflow preventer is installed.
Is a Building permit required to install the Backflow Preventer?
Yes. The installation of backflow preventers must meet the requirements of the Ontario Building Code, therefore a building permit must be obtained from the Town’s Building Services prior to installation. For additional information on the building permit application please contact the Towns Building Services department.
Why do Backflow preventers need to be tested periodically?
Backflow preventers have internal parts that can wear and tear, so they must be tested periodically, by qualified persons, to ensure they are working properly.
Where can I obtain the required forms?

The forms can be found under the Applications and Forms section on this webpage.

Who is authorized to perform the work required for the Backflow Prevention Program?

Only those persons with the required qualifications listed in the Authorized Functions List, attached as Schedule "A" to the by-law may carry out the corresponding functions shown. Persons performing Cross Control Surveys and Testing of Backflow Preventers must provide to the Town proof of qualification along with the following:

  • a current and valid Cross-Connection Control Specialist Certificate issued by the Ontario Water Works Association (OWWA)
  • a valid calibration certificate for their testing equipment
  • proof of Commercial General Insurance (CGI) in good standing

Companies registered with Town’s Backflow Prevention Program can be contacted and hired by property owners to survey, install and test backflow devices. Before hiring a contractor ensure he/she has proper certification.

Note: The Town of Aurora does not endorse Qualified Companies or Qualified Persons and does not accept liability or assume responsibility for work completed by companies under this program.

How can a qualified company/qualified person register for the BFP program?

If you would like to register with Town’s Backflow Prevention Program, please complete a Qualified Company & Qualified Person Registration form found under downloads on this page and submit it to us using the methods indicated on the form, along with all applicable credentials as specified.
What are the estimated costs to property owners?
The initial cost would depend on the fees charged by a qualified person to undertake the survey, install the backflow preventers and perform the tests. The backflow preventer cost would depend on the type of device recommended for installation and the location. Once the device is installed and tested, the cost to the owner would be the annual cost of testing and any required repairs.
Will there be incentives or rebates to property owners?
No. The program is mandatory to ensure that the Town’s drinking water remains safe for consumption.

For more information, send us an email at:

Get Involved
Property owners of all IC&I and multi-residential (6 or more units) please complete the Information Request Form and to submit it to the Town by January 31, 2020.

Property owners must undertake a Cross Control Survey using the services of a qualified person and submit the reports to the Town by March 31, 2020. A list of qualified persons to conduct the surveys and perform the testing is available below in the downloads section.

Share your thoughts on the Backflow Prevention Program by email at

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More information is available:

Additional Information

Qualified Persons Registry Business List

Only those persons listed in the Authorized Functions List (see Schedule “A” of the Backflow Prevention By-law) and prequalified with the Town of Aurora shall carry out the corresponding functions set out in this list.

“IMPORTANT NOTICE”: This is a list of businesses which employ “Qualified Persons” who have registered with Town of Aurora’s Backflow Prevention Program. A “qualified person” means a person who is certified or licensed to work in a specific field, based on levels of education and trade work experience achieved. A qualified person is permitted to carry out cross connection control functions in the Town of Aurora in accordance with “Schedule A” - Authorized Functions List. The Town strongly recommends you obtain several quotes before selecting a qualified person.

The Town does not make any representations or provide any endorsement with respect to any person listed, nor does the Town provide any warranty of services or prices.

Be advised that all “qualified persons” operate independently from the Town, please check their references, insurance, discuss costs, and obtain a WSIB clearance certificate before proceeding with any work. Thank you for your cooperation in this matter.

Plumbing Permits are required for all and any alterations to plumbing and are obtained from Building Services Department.


Qualified Persons Registry - August 12, 2022


Business NameContact InformationFUNCTIONS: Survey/Test Repair/Install

Dalcro Mechanical Contracting Ltd.



B. Jackson Plumbing Ltd.



Joe’s Mechanical



EOS Mechanical Inc.



Ocean Mechanical



ProActive Water Solutions



Denos Plumbing and Heating Ltd.



New Water Plumbing Inc.



Harris Plumbing




Tac Mechanical Inc.

416-789-8400 x 2


Rapid Plumbing Inc.



M-L Fire & Burglary Alarms Ltd


Sprinkler and Fire

Protection Only

DanMac Plumbing & Drain Service Ltd.



A&A Plumbing & Mechanical Services



Backflow Specialties Inc.



The Plumbers Edge Inc.




Naylor Building Partnership



Nor-Line Plumbing & Mechanical Ltd.



McWatters Mechanical Ltd.


Hometech Environmental Ltd 416-562-0978

Glad Mechanical 416-605-1755


Hi-Tech Plumbing 416-881-3923

Caledon Creek Mechanical Ltd 416-453-6447

Mainline Plumbing Services Inc. 905-761-0073

Under Pressure Plumbing

Services Inc.


Modern Niagara Building



Blackforest Plumbing 905-252-9994


Onyx Fire Protection Services


Sprinkler and Fire

Protection Only

Firenza Plumbing & Heating Ltd



Griffiths Plumbing


Water Bridge Environmental Solutions 905-679-3713



JDI Plumbing Ltd 647-272-1902

MRB Mechanical & Heating 416-609-9290

Carter Plumbing & Maintenance 705-730-5637

Classic Fire 416-740-3000

Sprinkler and Fire

Protection Only

Belair Plumbing & Mechanical 905-713-3434


Aqua-Flow Mechanical



Royal Plumbing Contracting

2019 LTD



Apex Plumbing & Drains Inc.



Jaywal Mechanical



Braywood Services Inc. (905) 853-6049


Attard Plumbing

(647) 349-0609


Bering Mechanical Ltd

(416) 231-1414


Allure Mechanical

(416) 896-0499


Heat Air Mechanical

(416) 736-7447

 G Bates Plumbing - Bates Group Inc.

 (905) 850-7777

 Newmarch Technical Systems

 (905) 640-8031

Backflow Science

(416) 268-7301

ZG Golden King Plumbing

(647) 887-5699

Bruce Clark and Son Plumbing & Mechanical

(416) 677-1591

Carefree Plumbing

(416) 241-9475

Concord Plumbing & Heating

(905) 265-0660

Aviv Plumbing Inc.

(416) 678-8737

T.I.F. Mechanical Ltd.

(905) 751-5060

TBS Building Services

(647) 961-4709

Lisi Services

(877) 321-5474

Bosse Mechanical

(416) 565-8214

Transparent Backflow Services

(519) 574-8776

Van Horn Plumbing and Heating

(416) 554-2213

Bob's Plumbing Services

(905) 727-3210


(416) 891-6731

Blackburn Plumbing

(647) 321-1946

H & M Plumbing

(647) 330-1720

Angus Building Solutions 

(647) 406-2951

Horizon Mechanical Contractors Inc

(416) 234-0225

G.O. Tap Plus

(416) 695-4377

Century Plumbing & Heating

(416) 891-9401

Bruno Plumbing & Contracting Inc

(905) 660-6163

Brady and Sedner Associates Ltd.

(416) 661-1981

Carless Plumbing (289) 803-5802
Stevenson Sprinkler & Fire Protection (905) 562-7575 
Sprinkler and Fire

Protection Only

Paul & Douglas Automatic Sprinklers Ltd (905) 564-2421
Sprinkler and Fire

Protection Only

AV Plumbing (416) 399-3562
YYZ Plumbing (416) 633-3232
Silver Plumbing (416) 820-6062
Nutech Fire Prevention (905) 549-0111
Sprinkler and Fire

Protection Only

BG Plumbing Inc (416) 525-8929
1000581204 Ontario Inc. O/A Guest Plumbing (905) 745-1963
TEC Mechanical

(905) 208-2723

Battershell Plumbing & Heating Ltd.

(905) 451-1696

ID Plumbing Services Inc.

(905) 265-2124

Vital Fire Mechanical

(905) 761-8289

Sprinkler and Fire

Protection Only

Applications and Forms

Council Reports and Presentations