Hard water: what it is, the signs, and what to do about it
Hard water has more dissolved calcium and magnesium in it. It’s found in most Canadian waters and is most common in groundwater, Health Canada says.[1] Health Canada says a health-based value for hardness is not warranted, and Ontario lists hardness as “not a health hazard”.[2] Health Canada calls hard water “both a nuisance and an economic burden”: scale, soap and upkeep, not a health risk. To see how hard your water is, check water hardness by city.
On this page
Signs of hard water at home
- White powdery or scaly deposits on taps, fixtures and in your plumbing.[1]
- Scale in your hot water tank or kettle. Health Canada says deposits in hot water tanks can lower energy efficiency and lead to early failure.
- Crusty deposits on kitchen utensils, and deposits on dishes from the dishwasher.[2]
- Needing more soap, and less lather. Health Canada says hard water increases soap use.
- Stiff laundry. Ontario describes a “starched effect on laundry”.
The Region of Waterloo, where most water comes from wells, says the minerals in hard water add to scale buildup in pipes and appliances.[3]
Permanent and temporary hardness
Health Canada describes two kinds.[1] Carbonate hardness comes out of the water when it’s heated, and causes the scale in hot water pipes and kettles. Non-carbonate hardness stays in the water when heated and doesn’t form scale, but still reduces soap lather.
Is hard water bad for you?
Drinking hard water
Health Canada says hardness, magnesium and calcium have low potential for toxicity through drinking water, and that a health-based value for hardness is not warranted.[1] The Region of Waterloo says its hard water is safe to drink.[3] In rare cases, water harder than 750 mg/L could give more calcium than Health Canada’s health-based value for calcium, and Health Canada says to find another drinking water source.
Hard water and skin
Health Canada says skin contact with water with high hardness may make atopic dermatitis (eczema) worse.[1]
Hard water and hair
We haven’t found a Canadian government source on hard water and hair, so we don’t cover it.
Hard water vs soft water
Hard water is generally less corrosive than soft water, Health Canada says.[1] Soft water can lead to corrosion in water systems and household plumbing, which is why utilities that treat hardness usually reduce it rather than remove it completely. Health Canada connects this to its guidance on controlling lead corrosion; if your home is older, see lead pipes.
There’s also a suggested range that balances scale and corrosion; see what level is ideal on our hardness page.
How to find out if you have hard water
- On city water: your city’s or region’s water report gives a hardness figure. Our hardness page lists figures and links for Ontario cities.
- On a well: have it tested at a licensed lab. Health Canada encourages well owners to test for hardness.[1] See well water testing.
- Home test strips: we haven’t found an Ontario or Health Canada source that compares strips with a lab test. See home water testing.
What you can do about hard water
- A water softener. Health Canada calls softeners the best available technology for reducing hardness at home.[1] See water softeners for how they work, the sodium they add to drinking water, and upkeep.
- A different soap or detergent. For moderately hard water, Ontario suggests an alternate soap and detergent.[2]
- Reverse osmosis at one tap. Health Canada says RO should be able to remove hardness but no RO system is certified for it, and high hardness fouls the membrane faster. See reverse osmosis.
What about a “hard water filter” for the shower? We found no Canadian government source on shower filters for hard water. The certified option for hardness that Health Canada names is a softener certified to NSF/ANSI 44.[1]
Is water in Canada hard or soft?
It depends on the source. Health Canada says hardness is found in most Canadian waters and is most common in groundwater.[1] In Ontario, lake-fed city systems and well systems can differ a lot; see water hardness by city.
Sources
- Health Canada, Guidelines for Canadian Drinking Water Quality: Operational Parameters. Checked . ↩︎
- Government of Ontario, Testing and treating private water wells. Checked . ↩︎
- Region of Waterloo, Hard Water Treatment. Checked . ↩︎