Commercial Water Treatment for Toronto and the GTA
Boiler, cooling tower and closed-loop programs from a Canadian manufacturer with a Toronto office.
- Programs built on Toronto's Lake Ontario water chemistry
- Remote monitoring and reporting with DataGuard 2.0
- Serving building owners and plants since 1960
Toronto office | Mississauga warehouse | AWT Member
Request a Water Treatment Assessment
No obligation. We’ll review your situation and recommend next steps.
What Toronto water means for your systems
Toronto’s treated water comes from Lake Ontario. For 2025 the City reported average hardness of 119 mg/L as CaCO3, alkalinity of 93 mg/L, pH 7.5, chloride of 27.5 mg/L and conductivity around 324 µS/cm. That is moderately hard water with several times the chloride of Edmonton or Calgary water. Hardness sets how many cycles a cooling tower can run before scale forms, and chloride raises the corrosion risk on steel and copper.
Because the source water is well documented, we can usually design your program from the utility data and your system details. We add a site test when it would change the recommendation, such as confirming silica before setting tower cycles or diagnosing a system with corrosion or scale problems.
Scale in cooling towers
At 119 mg/L hardness, tower cycles need real limits, set from data.
Chloride and corrosion
Higher chloride raises corrosion risk. Inhibitor choice has to account for it.
Legionella risk
Cooling towers need a documented water management approach.
Sewer discharge rules
Toronto's Sewers By-law limits what can go to sanitary sewer and keeps everything but rain and snowmelt out of storm drains.
A local rep, with senior technical support
Guardian has a sales office in Toronto and a warehouse in Mississauga. Our GTA representative handles both water treatment and industrial accounts, and Guardian’s Canadian and US vice presidents are regularly in the area to support customers.
Guardian programs follow Association of Water Technologies (AWT) best practices and cover the whole system: pre-treatment equipment, automated chemical feed and controls, the treatment chemistry, and regular on-site service.
One Ontario example: a contractor’s 100 HP mobile boiler kept scaling because its softener let hardness through. Guardian specified and commissioned a twin-tank softener sized for up to 300 ppm hardness and 15 gpm, which ended the repeat acid washes and lowered the risk to boiler coils worth about $30,000.
DataGuard 2.0: Know What Your Systems Are Doing
DataGuard is Guardian’s data logging, analysis and reporting app, included with Guardian water treatment programs. Owners, operators and our service team all see the same data.
Colour-coded control ranges show at a glance whether each system is in range
Alerts flag treatment issues before they become serious
Remote connection to your controller automates data entry
Reports, test procedures and SDSs in one place, for every site you manage
Water Treatment Across the GTA
Guardian serves commercial buildings, hospitals, schools, residential towers and industrial plants across Toronto, Mississauga, Brampton, Vaughan, Markham, Oakville, Burlington and Hamilton.
Industrial cleaning in the GTA: industrial degreaser supplier for Toronto and the GTA.
Facility Types We Serve
- Commercial office buildings and towers
- Hospitals and healthcare facilities
- Schools and universities
- Hotels, resorts, and casinos
- Government and municipal buildings
- Data centers
- Industrial and manufacturing plants
- Airports and transportation hubs
Systems We Treat
- Steam and hot water boilers
- Open recirculating cooling towers
- Closed-loop heating and chilled water systems
- Domestic water disinfection for new and renovated buildings
- Pre-treatment equipment, including softeners and filtration
What Building Operators Say About Guardian
“Guardian Chemicals are the best. I’ve been using them for the past 8 years, no complaints. I take them wherever I go, if they aren’t onsite already. They’ll support any request you have as well as recommend what’s best for your building or plant.”
“With Guardian, knowing that the water is good in all our buildings now and our cooling towers are performing as they should be is what I value most. It wasn’t like this before we brought Guardian in.”
"Before starting with Guardian, we were experiencing issues with Legionella and Corrosion in our systems. Things have improved a lot over the last 2-3 years and we are very happy with the outcome."
What Happens When You Request an Assessment
A Guardian water treatment specialist will contact you to understand your facility, your systems, and your current challenges.
Our team will visit your facility to inspect your boiler systems, review your current treatment program, and assess water quality.
We’ll provide findings, recommendations, and a tailored treatment program proposal—with no obligation to proceed.
If the program makes sense for your facility, we’ll handle onboarding, commissioning, and ongoing service from day one.
Ready to talk about your systems?
Tell us the building, the systems and who supplies your water. We will start from what we already know about GTA water and tell you if a site test would change anything. Or call (800) 661-6544, or email info@guardianchem.com.
Frequently Asked Questions: Water Treatment in Toronto and the GTA
Yes. A GTA-based representative serves water treatment and industrial customers from our Toronto office, with support from Guardian’s Canadian and US vice presidents, who are regularly in the area.
Often not. Toronto publishes its treated water chemistry, and we use it with your system details to design the program. We add a site test when it would change the recommendation, for example to check silica before setting cooling tower cycles or to diagnose a system with corrosion or scale problems.
The City reported average hardness of 119 mg/L as CaCO3 for 2025, which is moderately hard. Chloride averaged 27.5 mg/L, several times the level in Edmonton or Calgary water, and that matters for corrosion control.
DataGuard is Guardian’s data logging, analysis and reporting app. It shows whether each system is within its control ranges, sends alerts, and keeps reports, test procedures and safety data sheets in one place. It is included with Guardian water treatment programs.
Yes. Guardian supports Legionella risk management and water management plans for cooling towers, alongside the treatment program itself.
Steam and hot water boilers, open cooling towers, closed-loop heating and chilled water systems, domestic water disinfection for new buildings, and pre-treatment equipment such as softeners.
Yes. We review your current program and system records, propose a replacement program and plan the changeover with your team.
Yes. Guardian Chemicals is Canadian-owned and has been in business since 1960, with blending plants in Canada and the United States.
Send the form on this page or call (800) 661-6544. A Guardian water treatment specialist responds within one business day.
Still have questions?
