La Prairie Water Hardness & Quality Report (2026)
Water Hardness
~60–119 mg/L
Moderately Hardestimated · not lab-verified
Source
river
pH Level
7.2
neutral = 7.0
Lead
0.004 mg/L
✓ Below action level
TDS
158.4 mg/L
Est. Daily Cost
$0.24
energy & soap waste
Source: Health Canada Water Quality · Updated 2026
0–60
mg/L
Soft
61–120
mg/L
Moderately Hard
121–180
mg/L
Hard
180+
mg/L
Very Hard
Appliance Damage Report
In La Prairie, your appliances are currently losing 12% efficiency due to mineral buildup.
| Appliance | In La Prairie | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 7.5 yrs | 8.5 yrs | -12% |
| Washing Machine | 10.6 yrs | 12 yrs | -12% |
| Water Heater | 13.2 yrs | 15 yrs | -12% |
Regional Water Comparison
How La Prairie compares to its nearest neighbours
| City | Hardness | Mineralization | Risk |
|---|---|---|---|
| ▶ La Prairie, Quebec | ≈ 60–119 mg/L | Medium | 🟡 Moderately Hard |
| Candiac, Quebec | ≈ 120–179 mg/L | Medium | 🟠 Hard |
| Brossard, Quebec | ≈ 60–120 mg/L | Medium | 🟡 Moderately Hard |
| Ile-des-Soeurs, Quebec | ≈ 60–120 mg/L | Medium | 🟡 Moderately Hard |
| Greenfield Park, Quebec | ≈ 60–120 mg/L | Medium | 🟡 Moderately Hard |
National Benchmark
How La Prairie compares to the Canada average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ La Prairie | ≈ 60–119 mg/L | 🟡 Low |
| Canada National Avg | 140 mg/L | 🟠 Moderate |
| Vancouver Top Rated | 3 mg/L | 🟢 None |
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What Makes La Prairie's Water Unique?
Local geology and source profile
La Prairie's municipal water utility serves about 25,000 residents in the Montérégie region, drawing its supply from the St. Lawrence River. This water undergoes treatment at the Eau de La Prairie treatment plant before distribution to the city and surrounding communities within the Roussillon Regional County Municipality. The broader St. Lawrence River watershed, including contributions from the Châteauguay River, shapes the water's characteristics before it reaches the intake.
Geologically, the area is situated in the St. Lawrence Lowlands, characterized by flat-lying Ordovician sedimentary rocks like limestones, dolomites, and shales. These formations, part of the Appalachian foreland basin, are known to dissolve over time. As the river water flows through these carbonate-rich bedrock and Pleistocene glacial till deposits, it picks up dissolved calcium and magnesium ions, resulting in a moderately mineralized supply typical of rivers in southern Quebec.
Homeowners in La Prairie may notice a moderate amount of scale buildup in appliances such as kettles and dishwashers, which can affect their efficiency over time and leave spots on glassware. You might also find that laundry detergents aren't as effective, and soap doesn't lather as readily during showers. To combat these effects, consider annual descaling of appliances or using vinegar rinses. For persistent spotting or scaling issues, installing a water softener is a good idea to help extend the life of your plumbing and improve cleaning performance.
Geology & Source: St. Lawrence Lowlands; Ordovician limestone and shale produce moderate hardness
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