Systems Overview: Water, Sewer, Stormwater

The City of Markham is proud of its water distribution, wastewater collection, and stormwater management systems provided and maintained for our residents, businesses, and industries.
Learn more about where our water comes from, what wastewater is and how stormwater is managed.
The City of Markham delivers safe and reliable drinking water.
Through a system of pipes, valves, hydrants, pumping stations, and reservoirs, we deliver high quality, reliable drinking water to our residents and businesses. Learn about where Markham’s water comes from and how it gets treated, tested and delivered to your home.
Drinking Water Treatment
Markham's water comes from Lake Ontario. It is treated in the City of Toronto and sometimes Peel Region. Water from Lake Ontario has has contaminants that can be harmful to us if we don’t clean the water. These include:
- Physical: materials that don't dissolve in water and make the water appear "dirty"
- Chemical: substances dissolved in the water from natural and manmade processes
- Biological: viruses, bacteria, algae, and other small living organisms (City of Toronto).
We treat water to meet the standards of the Ontario Safe Drinking Water Act, 2002. Markham’s water is monitored at all times for quality.
For a closer look at the treatment process, visit the City of Toronto website for more information.
Disinfection with Chloramine
The City of Toronto's water treatment facilities disinfect water using chloramine. It's a chemical compound that contains chlorine and ammonia.
Chloramination is the process of adding chloramine during the treatment process. This disinfects and kills microorganisms such as viruses, bacteria, and algae. Chloramine is used instead of chlorine because it lasts longer in the distribution system. It makes the water more resistant to contamination as it travels from Toronto to Markham.
Chlorine has been a safe and reliable tool for over a century. It's stopped the spread of waterborne disease. If you don't like the smell a chlorine in your drinking water, fill a pitcher and let it stand overnight in the refrigerator.
Fluoridation
Fluoride is a mineral that occurs naturally in the environment. It's found in soil, air, and water. Fluoride is added at the end of the water treatment process to help prevent tooth decay. Many dentists and health experts want cities to add Fluoride to water. Long-term scientific studies also show that it is helpful and safe.
Water Distribution System
After treatment, clean water is pumped to York Region. York Region does more testing, storage, and provides additional pressure for Markham's system. Markham then distributes the water to residents and businesses.
Markham's distribution system provides high quality treated water to about 350,000 customers daily. It has:
- Over 1,000 kilometres of watermains
- 11,000 watermain valves
- 8,500 municipal fire hydrants
Markham is a distribution-only system. We don’t own treatment, pumping, or storage facilities. Markham's water is tested to meet Ontario Regulation 170/03 standards. Licensed Waterworks staff collect water samples. These samples are analyzed at Caduceon Environmental Laboratories.
Watch this "Markham's Water Distribution System" video to learn more!
Property Owner VS City Responsibility
How it's all connected
The City is responsible for the public portion of the water distribution system – spanning from the water main to the municipal property line. Beyond the property line is the private portion of the system and is the responsibility of the property owner. If you suspect there is an issue with any component that the City is responsible for, please contact the Customer Contact Centre at customerservice@markham.ca or 905.477.5530.
Markham's Responsibility
- Service (Curb) Box: Protects the curb stop valve and should be secured and flush with the ground. Never touch or cover it.
- Curb Stop Valve: Located underground, this valve controls the flow of water from the water main to your property.
- Remote Meter Reading Device: A small box mounted on the exterior of your property that allows the City to obtain meter readings without entering the premise.
- Water Mains: More than 1,000 kilometres of underground pipes throughout the City that carry water to water service lines.
- Service Connection: The part of the pipe that runs from the water main to the curb stop valve in front of your property.
- Water Meter: Records the volume of water used by your property.
Property Owner's Responsibility
- Water Service Line: Pipe that runs between the curb stop valve and your property.
- Indoor Water Shut-off Valve: Shuts off the water supply to your property.
- Indoor Plumbing: The system of water pipes, drains, fittings, valves and fixtures in your building that distribute water.
Property owners shall provide free, clear and unobstructed access to the water meter at all times. Tampering or any alteration to the water meter is prohibited under the City’s Water Use By-law 2019-53.
Markham's Tap Water
It's safe to drink Markham's Tap Water because it's…
- Healthy — a great calorie-free alternative to sugary drinks or caffeine
- Convenient — delivered right to your home or workplace
- Inexpensive — 1000 times less expensive than bottled water
- Well-Tested — Waterworks staff test Markham water several times a day
- Green — bottled water creates unnecessary waste and litter. It also takes energy to bottle, package, cool, and move.
Markham does not have a lead issue as the City does not have any lead pipes in our water distribution system on the public side.
Get a reusable water bottle and bring it with you! Reduce the amount of waste created by single-use plastic bottles.
"Our top priority is providing high quality drinking water to all our customers. We are constantly testing to ensure all standards and regulations are met for a safe, clean and healthy drinking water supply". — Eddy Wu, Director of Environmental Services
Contact
8100 Warden Avenue
Markham, ON, L6G 1B4
Hours
8 AM to 5 PM