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Ottawa Drinking Water Quality
By OpenStats · Built from official Canadian sources
Direct municipal dataC
Water quality grade
Fair
Graded against Health Canada drinking water guidelines
Lead within guidelinepH in range
Hardness vs provincial average21 mg/L · prov. avg 182 mg/L
Lead vs provincial average0 μg/L · prov. avg 0.4 μg/L
Hardness
21 mg/L
Lead
0 μg/L
≤ 5 μg/L
pH
7.6
6.5–8.5 range
Hardness
21 mg/L
Soft
Lead
0 μg/L
Max: 5 μg/L
pH
7.6
6.5–8.5
Chlorine
0.5 mg/L
Max: 4 mg/L
From source to sink
Where Ottawa 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 storyOn the map
Where Ottawa water lives
Source waters and treatment plants pinned from published utility names. Open a pin below for the full OpenStreetMap view.
- CityOttawa
Municipal service area
- Source waterOttawa River
Ottawa River
- Treatment plantBritannia Water Purification Plant
Approximate pin near Ottawa (exact plant coordinates pending)
- Treatment plantLemieux Island Water Purification Plant
Approximate pin near Ottawa (exact plant coordinates pending)
Map data © OpenStreetMap contributors. Pins are approximate for orientation, not legal survey points.
Where it starts
Surface water
Research confidence: high
Named source waters
- Ottawa River
Treatment plants
Britannia Water Purification Plant
West-end plant (c. 1961) at Cassels Street; nominal capacity 360 ML/day. Coagulation, flocculation, sedimentation, filtration, and disinfection; identical process train to Lemieux Island.
Lemieux Island Water Purification Plant
Central plant (c. 1931/1932) on Lemieux Island; nominal capacity 400 ML/day. Shares the Ottawa River source and multi-barrier process with Britannia.
How it reaches your street
Central system blends both plants into a common network of roughly 3,000 km of watermains with reservoirs and elevated tanks, serving about 90% of Ottawa’s population. Smaller communal well systems serve outlying villages (Carp, Vars, Munster, Richmond area, Greely).
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Reading this page
Ottawa's most recent drinking water sample (2026-07-22) reports hardness of 21 mg/L, classified as soft, and pH 7.6, drawn from a surface water source and treated at Ottawa Water Treatment Plant. Lead measured 0 μg/L and fluoride 0.5 mg/L.
Free chlorine measured 0.5 mg/L in this sample. No E. coli was detected in this sample.
Ottawa's hardness of 21 mg/L is below the Ontario average of 182 mg/L across 51 tracked municipalities, with a provincial average pH of 7.5.
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.
One or more parameters exceed a Health Canada drinking water guideline or turbidity target.
Figure 1 · From source to sink
How drinking water reaches your tap
Compared to provincial average
Ontario · 51 cities in sample
Hardness (city vs Ontario avg)21 mg/L
pH (city vs Ontario avg)7.6
Lead (city vs Ontario avg)0 μg/L
Fluoride (city vs Ontario avg)0.5 mg/L
Provincial average: hardness 182 mg/L · pH 7.5 · lead 0.4 μg/L · fluoride 0.6 mg/L
Full parameters
| Parameter | Reading | Health Canada guideline | Status |
|---|---|---|---|
| Hardness | 21 mg/L | No health limit (aesthetic) | Compliant |
| pH | 7.6 | 6.5–8.5 | Compliant |
| Lead | 0 μg/L | ≤ 5 μg/L | Compliant |
| Fluoride | 0.5 mg/L | ≤ 1.5 mg/L | Compliant |
| Chlorine (free) | 0.5 mg/L | ≤ 4 mg/L | Compliant |
| Turbidity | 3.3 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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Source · City of Ottawa Britannia water purification plant summary. Last updated 2026-07-22. Refreshed on the site's automated schedule.