CALGARY WATER GUIDE
Calgary Water Quality
Calgary’s tap water is treated, tested and safe to drink. It is also hard, and the hardness changes with the season and with the river your neighbourhood draws from. This guide puts the City of Calgary’s 2025 numbers and Health Canada’s advice in one place, so you can decide whether you want to change anything at home. Know your water before you treat it.
Calgary water at a glance (2025)
| Measure | City of Calgary 2025 figure |
|---|---|
| Hardness, city-wide | 141 to 274 mg/L as CaCO3 |
| Bearspaw plant (Bow River) | 141 to 200 mg/L, average 174 |
| Glenmore plant (Elbow River) | 181 to 274 mg/L, average 224 |
| Chlorine residual, city-wide | 0.82 to 2.01 mg/L |
| Drinking water tests completed | 208,736 |
Source: City of Calgary, Water quality, hardness and data, and the City’s 2025 plant summaries for Bearspaw and Glenmore. Checked 2026-10-03.
Two rivers, two treatment plants
Calgary draws its water from two rivers and treats it at two plants. In the City’s words: “Generally, people in the northern half of the city receive water from the Bow River through the Bearspaw Water Treatment Plant. Residents in the south receive most of their water from the Elbow River through the Glenmore Water Treatment Plant.” (City of Calgary)
Keep the City’s words “generally” and “most” in mind. The split is not a hard line, and the City offers no lookup by address. If you live near the middle of the city, a test at your tap tells you more than a map.
The same water goes beyond the city limits. The City says it “provides drinking water to The City of Chestermere, The City of Airdrie, The Town of Strathmore and portions of Foothills County, Rocky View County and Tsuut’ina Nation.” (City of Calgary, fluoride page) If your home is in another town, such as Cochrane or Okotoks, the numbers on this page do not describe your water. Ask your own supplier for its report.
How hard is Calgary’s water?
The City explains why: “Calgary’s water is considered hard because of the amount of calcium and magnesium in the water from the Bow and Elbow Rivers.” Those minerals “come from rock such as limestone that dissolves in our river system.” (City of Calgary)
Across the city, 2025 hardness ranged from 141 to 274 mg/L as CaCO3. In each quarter of 2025, both the low and the high for Glenmore (Elbow River) sat above those for Bearspaw (Bow River).
2025 hardness by plant and quarter (mg/L as CaCO3)
| Plant (river, area) | January to March | April to June | July to September | October to December | Full year (average) |
|---|---|---|---|---|---|
| Bearspaw (Bow River, generally north) | 151 to 200 | 141 to 192 | 151 to 177 | 168 to 197 | 141 to 200 (174) |
| Glenmore (Elbow River, most of the south) | 208 to 274 | 181 to 245 | 191 to 216 | 213 to 248 | 181 to 274 (224) |
Sources: quarterly ranges from the City’s “Water Hardness, mg/L CaCO3” table, marked “ranges for 2025” (City of Calgary). Full-year minimum, maximum and average from the City’s 2025 plant summaries (Bearspaw, Glenmore).
The season matters too. The City says “the lowest hardness levels are typically during spring snowmelt” and the highest are “between December and February.” The table shows it: Glenmore’s top reading of 274 mg/L came in the January to March quarter.
At home, the City says hard water can mean “difficulty making lather or suds while washing and/or a build-up of minerals on taps and other fixtures.” That is the white crust on a kettle element, the spots on glasses, and the film on a glass shower door.
Is hard water a health concern?
No, according to the City: “There are no known health effects associated with calcium and magnesium minerals in drinking water.” The City’s 2025 table lists “No limit” for hardness. (City of Calgary)
The City adds one caution about the fix, not the water: “conventional water softening systems (those that use salts) may not be suitable for people on sodium-reduced diets.” It also recommends that “consumers thoroughly research the various water softener systems available before deciding whether or not to soften their water.” If someone in your home follows a sodium-reduced diet, raise it before you choose a softener.
Chlorine in Calgary water
The City adds chlorine during treatment. On its taste and odour page it explains, “We add chlorine to disinfect your water,” and it may raise the dose at times such as spring runoff “to ensure that your drinking water remains safe.” (City of Calgary, taste and odour)
2025 chlorine residual (mg/L)
| Supply | Minimum | Maximum | Average |
|---|---|---|---|
| Bearspaw (Bow River) | 0.82 | 1.40 | 1.06 |
| Glenmore (Elbow River) | 0.88 | 2.01 | 1.23 |
| City-wide range | 0.82 | 2.01 |
Sources: City 2025 plant summaries (Bearspaw, Glenmore); city-wide range and the “≥0.2” minimum from the City’s water data table.
If you notice the taste, the City has its own tip: “fill a container of water and keep it in the fridge for drinking. Much of the chlorine will dissipate from the water overnight.” In late summer and early fall, some people notice an earthy or musty taste from geosmin, which the City calls “a harmless, naturally occurring compound.” The City says the water “remains safe to drink and continues to meet all guidelines set by provincial and federal health standards.” (City of Calgary, taste and odour)
What Health Canada says about home water treatment
Health Canada’s starting point is reassuring: “In general, your drinking water doesn’t usually need more treatment for health-related reasons if you get it from a community water system that meets the Guidelines for Canadian Drinking Water Quality.” It also lists, among the reasons people buy devices, to “change the taste and appearance of the water, as a matter of personal choice.” (Health Canada, Drinking water and health: Treatment)
If you do buy a device, Health Canada says, “we strongly recommend that you buy a treatment device that’s certified as meeting the applicable NSF/ANSI performance standard.” It names six:
| Standard | Health Canada’s name for it | What it covers, in plain words |
|---|---|---|
| NSF/ANSI 42 | Drinking Water Treatment Units, Aesthetic Effects | Filters for taste and odour, such as chlorine |
| NSF/ANSI 44 | Cation Exchange Water Softeners | Softeners for hardness (calcium and magnesium) |
| NSF/ANSI 53 | Drinking Water Treatment Units, Health Effects | Filters verified to reduce specific substances with a health effect, named on the certificate |
| NSF/ANSI 55 | Ultraviolet Microbiological Water Treatment Systems | UV systems. Health Canada: Class A for disinfecting contaminated water; Class B for “additional bactericidal treatment of drinking water that’s already safe” |
| NSF/ANSI 58 | Reverse Osmosis Drinking Water Treatment Systems | Reverse osmosis units for a drinking water tap |
| NSF/ANSI 62 | Drinking Water Distillation Systems | Distillers |
Sources: standard names and UV classes from Health Canada. Plain-language column from NSF, Standards for Water Treatment Systems, which also notes the numbers “are not a ranking or rating system.”
Health Canada explains what certification means: the “device doesn’t add anything harmful to the water” and the “performance claims made by the manufacturer (those claims covered by the standard only) have been verified as being true.” Claims outside the standard are not verified, so Health Canada recommends you “review all packaging and promotional literature to identify which performance claims the certification body has verified.”
Two more notes from Health Canada worth knowing. Reverse osmosis systems “remove minerals like calcium and magnesium from drinking water,” and “in Canada, water is a minor source of such minerals when compared to foods.” And on upkeep: “carefully follow the maintenance instructions included with the device to ensure it continues to work well.”
On fluoride, which the City reintroduced on June 30, 2025: the City says fluoride “can be removed from your drinking water at home using a specialized filtration system. Look for equipment certified to NSF/ANSI 58.” (City of Calgary, fluoride)
When treatment is a preference
Put the City’s data and Health Canada’s advice side by side and the picture for a Calgary home is clear. Treatment here is a choice about comfort and upkeep, and the right equipment depends on the problem you want to solve:
- White scale on taps, kettles and shower glass, or soap that won’t lather: that is hardness. The equipment built for it is a softener (NSF/ANSI 44). A filter is not a softener.
- Chlorine taste or odour: the City’s fridge tip handles a jug. For a tap or the whole house, look at filters certified to NSF/ANSI 42.
- Drinking and cooking water at one tap, or fluoride removal: reverse osmosis (NSF/ANSI 58).
- Nothing bothers you: Health Canada’s guidance says community water that meets the guidelines doesn’t usually need more treatment for health reasons. Doing nothing is a fair answer.
How to know your own water
The City’s numbers describe treated water “entering the distribution system” (Bearspaw 2025 summary). Between the plant and your glass sit the City’s mains and your home’s own pipes and fixtures, and your side of the city and the season change the hardness you get. That is why the place to start is a test at your own tap.
- Read your side of the city. Use the quarterly table above as a range, not a reading.
- Test at your tap. An Alberta Indoor Comfort technician can measure your water and walk you through the numbers next to the City’s 2025 range for your side of the city.
- Have a safety question about the City’s water? Call 311. The City says, “If you have any other questions about the taste, smell or odour of your water please call 311.”
Talk it through with us
If you want to know your numbers before you decide anything, we can test your water and show you what they mean. If the answer is that you don’t need equipment, we will say so.
or call 587-792-1456 (weekdays 8 a.m. to 5 p.m. MT)
Related: Whole home water filtration · Water softeners · Reverse osmosis · All water treatment
Our water assessment measures and reports on your water. It does not diagnose, treat, cure or prevent any illness or condition, and it is not a laboratory test for contaminants.
Written by: The Alberta Indoor Comfort team
Last reviewed: 2026-10-05
Data checked: City of Calgary 2025 water data (live page and plant summaries) and Health Canada treatment guidance, 2026-10-03. Update this page when the City publishes its 2026 summaries.
Sources
- City of Calgary, Water quality, hardness and data: https://www.calgary.ca/water/drinking-water/water-quality-water-hardness-water-data.html
- City of Calgary, Bearspaw Water Treatment Plant Summary, January 1 to December 31, 2025: https://www.calgary.ca/content/dam/www/uep/water/documents/water-documents/bearspaw-water-treatment-plant-summary-2025.pdf
- City of Calgary, Glenmore Water Treatment Plant Summary, January 1 to December 31, 2025: https://www.calgary.ca/content/dam/www/uep/water/documents/water-documents/glenmore-water-treatment-plant-summary-2025.pdf
- City of Calgary, Drinking water: Taste, odour and appearance: https://www.calgary.ca/water/drinking-water/water-taste-odour-appearance.html
- City of Calgary, Fluoride in Calgary’s water: https://www.calgary.ca/fluoride
- Health Canada, Drinking water and health: Treatment: https://www.canada.ca/en/health-canada/services/environment/drinking-water/treatment.html
- NSF, Standards for Water Treatment Systems: https://www.nsf.org/consumer-resources/articles/standards-water-treatment-systems