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Markham Flood Control Program Logo

What is Markham’s Flood Control Program?

In February 2013, Council approved a long-term 30-year Flood Control Program which sets funding requirements to achieve level of service improvements for drainage systems in the City of Markham.    

The Flood Control Program is a long term, City-wide initiative to improve storm drainage capacity and limit surface and basement flooding risks in urban areas. Improvements will provide a more consistent level of service across Markham and help protect both public and private property. The program will also make critical infrastructure more resilient to climate change and extreme weather.

The City has prioritized the assessment and upgrade of older drainage systems, constructed prior to 1978, when modern day standards for stormwater drainage were implemented.  Areas constructed prior to 1978 are more susceptible to flooding as they were not designed to convey the amount of water expected during infrequent, very large storm events.   

The Citywide Flood Control Program includes projects that range from major capital improvements to the storm system, to education programs and subsidies for residents to improve their private plumbing systems. 

Staff updated the cost estimates in 2018 for all phases of the Flood Control Program, with an estimated cost of $367-$382M.  To date, the City has received two funding grants for the program: 

  • $6.5M from the Clean Water and Wastewater Fund (CWWF) – Ministry of Infrastructure of Ontario
  • $48.6M from the Disaster Mitigation and Adaptation Fund (DMAF) – Infrastructure Canada

In 2013, Council approved the allocation of $2M per year from the Federal Gas Tax Grant.  The costs of the program are otherwise funded by the City’s stormwater fee, charged to all property owners; residential and non-residential. This fee is applied to the Final Tax bill for each property owner in Markham. For more information, visit Stormwater Fee

Image of flooded parking area with cars.Image of pipe installation

Flood Control Program Projects

The City has prioritized the upgrades within West Thornhill, the Don Mills Channel (Woodbine/Denison Area) and Markham Village and Unionville, based on the known locations of basement flooding clusters.  Other areas within the City will be assessed at a later date.  The current status and location of all areas to be assessed through the program are shown in the maps below.

For more information on our flood control projects, please see the following links below:

  • Don Mills Channel
  • West Thornhill
  • Markham Village & Unionville
  • Private Plumbing Protection Program

Map of flood control area in Markham

Stormwater Fee

To help fund the program, a Stormwater Fee is charged to all properties in the City of Markham. This fee, combined with revenue from the Canada Gas Tax and other grants, will provide dedicated funds for both approved and future Stormwater infrastructure improvement projects City-wide.

Pursuant to the City of Markham’s By-law 2019-100 “The Non-Residential Stormwater Fee rate of $29.00 per $100K of CVA is to be adjusted to compensate for the average change in CVA.” The resulting annual adjustments to the non-residential Stormwater Fee rate are summarized in the table below:

Year Non-Residential Rate per $100,000 in CVA
2016 $29
2017 $28
2018 $27
2019 $26
2020 $0.00
2021 $28.5
2022 $29
Subsequent Years
%2 increase, adjusted for average change in CVA

The adjusted non-residential Stormwater Fee rate is not retroactive – it is applicable to the year in which it was adjusted.

Council Decisions and Resolutions:


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