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Drinking Water Quality and Supply

St. John's Drinking Water Quality

By OpenStats · Built from official Canadian sources

Direct municipal data
See where St. John's water comes from
B

Water quality grade

Good

Graded against Health Canada drinking water guidelines

Lead within guidelinepH in range
Hardness vs provincial average25 mg/L · prov. avg 141 mg/L
Lead vs provincial average0.2 μg/L · prov. avg 0.3 μg/L
Hardness
25 mg/L
Lead
0.2 μg/L
≤ 5 μg/L
pH
6.9
6.5–8.5 range
Hardness
25 mg/L
Soft
Lead
0.2 μg/L
Max: 5 μg/L
pH
6.9
6.5–8.5
Chlorine
0.7 mg/L
Max: 4 mg/L

From source to sink

Where St. John's water comes from

Lakes, rivers, wells, and treatment plants behind the kitchen tap, in plain language. Chemistry grades above are a separate lab snapshot; this section is the route the water travels.

Open the full tap story

On the map

Where St. John's water lives

Source waters and treatment plants pinned from published utility names. Open a pin below for the full OpenStreetMap view.

Map showing drinking-water locations for St. John's

Map data © OpenStreetMap contributors. Pins are approximate for orientation, not legal survey points.

Where it starts

Surface water

Research confidence: high

Named source waters

  • Windsor Lake
  • Broad Cove River watershed
  • Little Powers Pond
  • Bay Bulls Big Pond
  • Petty Harbour Long Pond

Treatment plants

  • Windsor Lake Water Treatment Facility

    Treats Broad Cove River / Windsor Lake / Little Powers Pond watershed water; membrane microfiltration, UV, chlorine, lime/CO2 alkalinity adjustment; up to 70,000 m³/day.

  • Bay Bulls Big Pond Water Treatment Facility

    Largest plant; conventional DAF process with UV and chloramine disinfection; up to 85,000 m³/day; also supplies regional partners (e.g. Mount Pearl / Conception Bay South area per provincial inventory).

  • Petty Harbour Long Pond Water Treatment Facility

    Newest city plant; rated about 14,500 m³/day.

How it reaches your street

Three surface-water plants feed city reservoirs (more than 95,000 m³ storage) and the distribution system. City does not fluoridate. Daily sampling from 70+ distribution locations.

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Partner

Lab water test for St. John's taps

Municipal reports cover the plant. A Tap Score kit tests the water at a St. John's tap for a broader contaminant panel.

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Compare filters · Water test kits · Hardness guide

Reading this page

St. John's's most recent drinking water sample (2026-07-22) reports hardness of 25 mg/L, classified as soft, and pH 6.9, drawn from a groundwater water source and treated at St. John's Water Treatment Plant. Lead measured 0.2 μg/L and fluoride 0.6 mg/L.

Free chlorine measured 0.7 mg/L in this sample. No E. coli was detected in this sample.

St. John's's hardness of 25 mg/L is below the Newfoundland and Labrador average of 141 mg/L across 4 tracked municipalities, with a provincial average pH of 7.3.

These readings summarize a single compliance snapshot, not a certification of the water reaching your tap. Test your own water periodically, especially on a private well, and consider a softener if hardness is classified hard or very hard.

How to use this page: read the headline metrics first, then where the water comes from (map and tap story), then the parameter table and source footer.

Health parameters meet Health Canada limits; turbidity above the 1 NTU typical target.

Health parameters meet Health Canada limits; turbidity exceeds the typical 1 NTU aesthetic target.

Figure 1 · From source to sink

How drinking water reaches your tap

Compared to provincial average

Newfoundland and Labrador · 4 cities in sample

Hardness (city vs Newfoundland and Labrador avg)25 mg/L
pH (city vs Newfoundland and Labrador avg)6.9
Lead (city vs Newfoundland and Labrador avg)0.2 μg/L
Fluoride (city vs Newfoundland and Labrador avg)0.6 mg/L

Provincial average: hardness 141 mg/L · pH 7.3 · lead 0.3 μg/L · fluoride 0.6 mg/L

Full parameters

ParameterReadingHealth Canada guidelineStatus
Hardness25 mg/LNo health limit (aesthetic)Compliant
pH6.96.5–8.5Compliant
Lead0.2 μg/L≤ 5 μg/LCompliant
Fluoride0.6 mg/L≤ 1.5 mg/LCompliant
Chlorine (free)0.7 mg/L≤ 4 mg/LCompliant
Turbidity2.7 NTU≤ 1 NTU (typical target)Exceeds guideline
Alberta water licences

WaterRegister.ca

On a private well or holding an Alberta water allocation licence? Water Register maps EPA licence records, transfer comparables, and watershed context across the province.

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Drinking water filters and test kits

Pitcher and under-sink filters, plus hardness strips and TDS meters for tap checks.

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Source · Government of Newfoundland and Labrador tap water quality report (Windsor Lake supply). Last updated 2026-07-22. Refreshed on the site's automated schedule.