Le Sud-Ouest Water Hardness & Quality Report (2026)
Water Hardness
Source
river
pH Level
7.3
neutral = 7.0
Lead
0.002 mg/L
✓ Below action level
TDS
127 mg/L
Est. Daily Cost
$0.20
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 Le Sud-Ouest, your appliances are currently losing 10% efficiency due to mineral buildup.
| Appliance | In Le Sud-Ouest | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 7.2 yrs | 8.5 yrs | -15% |
| Washing Machine | 10.9 yrs | 12 yrs | -9% |
| Water Heater | 12.6 yrs | 15 yrs | -16% |
Regional Water Comparison
How Le Sud-Ouest compares to its nearest neighbours
| City | Hardness | Mineralization | Risk |
|---|---|---|---|
| ▶ Le Sud-Ouest, Quebec | 74 mg/L | Medium | 🟡 Moderately Hard |
| Saint-Henri, Quebec | 99 mg/L | Medium | 🟡 Moderately Hard |
| Westmount, Quebec | 65 mg/L | Medium | 🟡 Moderately Hard |
| Verdun, Quebec | 123 mg/L | High | 🟠 Hard |
| Notre-Dame-de-Grâce, Quebec | 126 mg/L | High | 🟠 Hard |
National Benchmark
How Le Sud-Ouest compares to the Canada average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Le Sud-Ouest | 74 mg/L | 🟡 Low |
| Canada National Avg | 141 mg/L | 🟠 Moderate |
| Vancouver Top Rated | 3 mg/L | 🟢 None |
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What Makes Le Sud-Ouest's Water Unique?
Local geology and source profile
Le Sud-Ouest (a southwest Montréal borough encompassing Saint-Henri, Pointe-Saint-Charles, Verdun waterfront, and Côte-Saint-Paul) receives its drinking water through Ville de Montréal — Direction de l'eau potable, drawing directly from the St. Lawrence River via the historic Atwater Water Treatment Plant — one of Canada's largest and oldest water treatment facilities, fully updated with ozonation, biofiltration, UV disinfection, and chloramination. All supply meets the Guidelines for Canadian Drinking Water Quality (GCDWQ). Hardness is 74 mg/L (4.3 gpg) — classified as moderately hard by Health Canada.
Le Sud-Ouest is served from the Atwater plant, which draws from the St. Lawrence River at the west end of Montréal island where the river carries a blend of harder Ordovician limestone-influenced mainstream water and softer Precambrian Shield tributary inflows from the Ottawa and Saint-Maurice Rivers upstream. At this west-island location, the Shield dilution effect produces a moderate 74 mg/L supply — consistent with the range observed across Montréal's distribution network.
At 74 mg/L, Le Sud-Ouest residents experience only modest scale deposits in kettles and on tap aerators — descaling two to three times a year is adequate. Hot water tanks operate reliably at this hardness. Le Sud-Ouest's historic character — including Pointe-Saint-Charles, one of Montréal's oldest working-class neighbourhoods — means a significant proportion of the housing stock dates from before 1960. Montréal's Direction de l'eau potable advises residents in all pre-1970 properties throughout this borough to follow Health Canada lead guidelines and to request lead service line assessment and replacement.
Geology & Source: Supplied by Ville de Montréal — Direction de l'eau potable from the St. Lawrence River via the Atwater treatment plant — primary St. Lawrence supply with moderate Shield tributary softening reaches this southwest Montréal borough at 74 mg/L (4.3 gpg).