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Duncan tap water: Grade B, hardness 181 mg/L
By OpenStats · Built from official Canadian sources
Regional estimateB
Water quality grade
Good
Graded against Health Canada drinking water guidelines
Lead within guidelinepH in range
Hardness vs provincial average181 mg/L · prov. avg 142 mg/L
Lead vs provincial average0.5 μg/L · prov. avg 0.4 μg/L
Hardness
181 mg/L
Lead
0.5 μg/L
≤ 5 μg/L
pH
6.9
6.5–8.5 range
Hardness
181 mg/L
Very hard
Lead
0.5 μg/L
Max: 5 μg/L
pH
6.9
6.5–8.5
Chlorine
1 mg/L
Max: 4 mg/L
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Reading this page
Duncan's drinking water earns Grade B (Good). Hardness is 181 mg/L (very hard), and pH is 6.9 against Health Canada's 6.5–8.5 guideline.
Lead at 0.5 μg/L is below the 5 μg/L maximum, and fluoride is 0.6 mg/L against a guideline of ≤ 1.5 mg/L.
How to use this page: read the headline metric and provincial comparison first, then supply and treatment notes, then the source footer for the underlying dataset.
Watershed to tap
Supply and treatment
How Duncan draws, treats, and distributes drinking water, from municipal and utility publications. Chemistry grades above come from separate parameter records; this section does not invent plant lab figures.
Source type
Groundwater
Research confidence: high
Source waters
- Cowichan River sub-river / unconfined aquifer (four deep wells)
Treatment plants
Duncan municipal well system / chlorination
Four deep wells and two reservoirs near the Cowichan River; aquifer recharged by river and watershed filtration through pervious soils.
Distribution
Distribution covers Duncan and extends into portions of North Cowichan, CVRD Areas D/E, and Cowichan Tribes lands (~15,000 people).
Health parameters meet Health Canada limits; turbidity above the 1 NTU typical target and very hard water.
Health parameters meet Health Canada limits; turbidity exceeds the typical 1 NTU aesthetic target.
Figure 1 · Supply chain
From watershed to tap
Compared to provincial average
British Columbia · 58 cities in sample
Hardness (city vs British Columbia avg)181 mg/L
pH (city vs British Columbia avg)6.9
Lead (city vs British Columbia avg)0.5 μg/L
Fluoride (city vs British Columbia avg)0.6 mg/L
Provincial average: hardness 142 mg/L · pH 7.6 · lead 0.4 μg/L · fluoride 0.6 mg/L
Full parameters
| Parameter | Reading | Health Canada guideline | Status |
|---|---|---|---|
| Hardness | 181 mg/L | No health limit (aesthetic) | Compliant |
| pH | 6.9 | 6.5–8.5 | Compliant |
| Lead | 0.5 μg/L | ≤ 5 μg/L | Compliant |
| Fluoride | 0.6 mg/L | ≤ 1.5 mg/L | Compliant |
| Chlorine (free) | 1 mg/L | ≤ 4 mg/L | Compliant |
| Turbidity | 2.2 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.
Explore WaterRegister.ca →OpenStats pick
OpenStats picks for Duncan — chlorine + hardness
Duncan pairs 181 mg/L hardness with 1.0 mg/L chlorine — taste and scale show up together. Elite carbon for drinking, shower filter for chlorine, strips so you know when you need a softener.
As an Amazon Associate, OpenStats earns from qualifying purchases.
· Compare options- Shop on Amazon.caBrita 10-cup Elite pitcherOpenStats pick for Duncan — 1.0 mg/L chlorine taste on 181 mg/L water
- Shop on Amazon.caSR SUN RISE 20-stage shower filterDuncan’s 1.0 mg/L chlorine — bestselling shower filter on Amazon.ca
- Shop on Amazon.caFrizzlife SW20 under-sink filterNSF 53 lead reduction for Duncan older plumbing
- Shop on Amazon.caBrita Elite replacement filtersSix-month Elite cartridges for Duncan
- Shop on Amazon.caVARIFY hardness test strips181 mg/L at Duncan — pitchers do not soften; strips decide if you need a softener
Source · ECCC / municipal open data (seed). Last updated 2026-09-01. Refreshed on the site's automated schedule.