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Le Vieux-Longueuil Water Hardness & Quality Report (2026)

Water Hardness

73mg/L
Moderately Hard

Source

river

pH Level

7.3

neutral = 7.0

Lead

0.002 mg/L

✓ Below action level

TDS

125.5 mg/L

Est. Daily Cost

$0.19

energy & soap waste

Source: Health Canada Water Quality · Updated 2026

73mg/L as CaCO₃Moderately Hard

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 Vieux-Longueuil, your appliances are currently losing 10% efficiency due to mineral buildup.

ApplianceIn Le Vieux-LongueuilSoft Water CityEfficiency Loss
Kettle
7.2 yrs
8.5 yrs-15%
Washing Machine
10.9 yrs
12 yrs-9%
Water Heater
12.7 yrs
15 yrs-15%

Regional Water Comparison

How Le Vieux-Longueuil compares to its nearest neighbours

CityHardnessMineralizationRisk
Le Vieux-Longueuil, Quebec73 mg/LMedium🟡 Moderately Hard
Longueuil, Quebec115 mg/LMedium🟡 Moderately Hard
Mercier–Hochelaga-Maisonneuve, Quebec72 mg/LMedium🟡 Moderately Hard
Laflèche, Quebec70.5 mg/LMedium🟡 Moderately Hard
Greenfield Park, Quebec90.5 mg/LMedium🟡 Moderately Hard

National Benchmark

How Le Vieux-Longueuil compares to the Canada average

BenchmarkHardnessAppliance Risk
Le Vieux-Longueuil73 mg/L🟡 Low
Canada National Avg141 mg/L🟠 Moderate
Vancouver Top Rated3 mg/L🟢 None

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What Makes Le Vieux-Longueuil's Water Unique?

Local geology and source profile

Source: RiverTDS: 125.5 mg/LpH: 7.3

Le Vieux-Longueuil (the historic urban core of the City of Longueuil) receives its drinking water through Ville de Longueuil, part of the same integrated St. Lawrence River supply network serving the broader Longueuil agglomeration on the South Shore. Water is treated at the Longueuil Water Treatment Plant using coagulation, sedimentation, filtration, ozonation, and chloramination, fully meeting the Guidelines for Canadian Drinking Water Quality (GCDWQ). Hardness in Le Vieux-Longueuil's distribution zone is 73 mg/L (4.3 gpg) — classified as moderately hard by Health Canada, notably softer than the broader Longueuil average, reflecting the supply zone's particular blend of St. Lawrence and tributary sources.

Le Vieux-Longueuil's supply zone draws from a treatment point influenced by both the St. Lawrence River and upstream blending with Rivière des Prairies tributary flow carrying softer water from Precambrian Shield highlands to the north. As this softened blend is distributed through the historic downtown Longueuil supply zone closest to the river, measured hardness at 73 mg/L is substantially lower than in outer Longueuil districts receiving more upstream-influenced supply.

At 73 mg/L, Le Vieux-Longueuil residents see only modest scale deposits in kettles and on tap aerators — descaling two to three times a year is sufficient. Hot water tanks operate efficiently at this hardness without dedicated scale treatment. In Le Vieux-Longueuil's older housing stock — including many heritage buildings from the 18th and 19th centuries near the historic town centre — Ville de Longueuil advises residents to follow Health Canada guidance on lead precautions and to participate in available lead service line replacement programmes.

Geology & Source: Supplied by Ville de Longueuil from the St. Lawrence River via the Longueuil Water Treatment Plant — supply in this historic borough's distribution zone is softened by blending with Rivière des Prairies-influenced water, producing water at 73 mg/L (4.3 gpg).

Other Quebec Water Reports

Frequently Asked Questions

Is Le Vieux-Longueuil's water safe to drink?
Yes. Le Vieux-Longueuil's water meets all federal safety standards. The hardness is 73 mg/L (Moderately Hard), which is safe to drink. High hardness affects appliances and taste, but poses no health risk.
Do I need a water softener in Le Vieux-Longueuil?
Le Vieux-Longueuil's water is moderately hard at 73 mg/L. A water softener is generally not necessary, though a carbon filter can improve taste and remove any remaining chlorine.
How does Le Vieux-Longueuil compare to the Canada average?
The Canada national average is 141 mg/L. Le Vieux-Longueuil at 73 mg/L is 68 mg/L below the national average. The softest major city is Vancouver at just 3 mg/L.