Scarborough (Toronto) Drinking Water Quality Overview – 2025
Scarborough is served by the City of Toronto’s drinking water system, drawing from Lake Ontario. The water meets all provincial standards with 100% compliance. While safe, many Scarborough residents — especially in post-war neighbourhoods — choose premium filtration to improve taste, manage hardness, and address potential lead from older plumbing.
Quick Facts
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100% Regulatory Compliance in 2025
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4 Toronto Plants Treatment Source
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~630,000+ Scarborough Residents Served
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~115–120 mg/L Typical Hardness
Water Source & Treatment
Source: Lake Ontario — same as the rest of Toronto. Water is treated at R.C. Harris, R.L. Clark, F.J. Horgan, and Island Water Treatment Plants, then distributed throughout Scarborough via Toronto’s trunk and local mains.
Scarborough has a large mix of residential, commercial, and high-rise areas with varying pipe ages.
Original Velora reference chart
The historical chart below is retained with the original overview. Its reference column mixes different kinds of guidance: the current comparison above distinguishes them. In particular, sodium’s 20 mg/L figure is a reporting level, not its 200 mg/L aesthetic objective; Ontario’s lead standard is 10 µg/L. Original summary figures and compliance statements need to be checked against the relevant municipal report.
| Parameters | Typical Level | Ontario Standards (MAC) | Notes: |
|---|---|---|---|
| PH | 7.4 – 7.7 | 6.5 – 8.5 | Optimal range |
| Total Hardness: | ~125–130 mg/L | No MAC | Harder than Central Toronto |
| Calcium | 35 - 38 mg/L | --- | Contributes to hardness |
| Sodium | 15–18 mg/L | 20 mg/L (AO) | Low: suitable for most low-sodium diets |
| Lead (at treatment plant) | < 1 µg/L | 5 µg/L | No lead added at plants |
| THMs (average) | < 50 µg/L | 100 µg/L | Disinfection byproduct: well below limit |
Note: All regulated microbiological, chemical, and radiological parameters met Ontario Drinking Water Quality Standards in 2025.
Key Water Quality Parameters (2025)
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pH: 7.4–7.7 (optimal)
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Total Hardness: ~115–120 mg/L (moderately hard)
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Calcium: ~33 mg/L
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Sodium: 14–15 mg/L (low)
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Lead (at plant): <1 µg/L (no lead added at source)
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THMs: <50 µg/L (well below limit)
All regulated parameters met Ontario Drinking Water Quality Standards.
Lead Service Lines & Older Plumbing
Treated water has no lead. However, many Scarborough homes built before the mid-1950s have lead service lines, and pre-1990 homes may have lead solder. Toronto’s free lead service line replacement program (city portion) applies. Free testing kits are available via 311.
Common Resident Concerns
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Chlorine/chloramine taste and odour
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Seasonal earthy/musty flavours from Lake Ontario algae
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Hard water scale, dry skin/hair, and appliance buildup
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Trace organics and emerging contaminants
Why Scarborough Homeowners Choose Velora Filtration
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Superior taste and clarity
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Water softening for healthier skin, hair, and longer-lasting appliances
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Extra protection against trace contaminants and distribution variability (including legacy lead risk in older areas)
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Whole-home benefits for showers, laundry, and plumbing
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Peace of mind for families in post-war and established Scarborough neighbourhoods
Book A Free In-Home Water Analysis!
Velora Water (Vaughan) specializes in custom whole-home and reverse osmosis systems tailored to Scarborough / Toronto water.
www.velorawater.com — Serving Scarborough, Toronto, and the GTA
We offer:
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Whole-home filtration systems
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Reverse osmosis drinking water systems
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Water softeners and conditioners
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Iron, tannin, and specialty filters
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UV disinfection
Disclaimer
Summarizes official 2025 City of Toronto reports. Tap water quality can vary by home. Professional on-site testing recommended.
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Original Velora report graphics
These graphics accompany the existing Velora overview. Consult the relevant municipal report for current measurements and sampling details.
