Several factors influence when and how often you should test your water. Where do you get your water from? Has that source changed? Have you made any plumbing changes recently? Is there reason to believe your water may be contaminated? Has anyone in your family experienced illness affecting more than one person, lasting longer than normal?
If you receive your water from a public supply—for example, a municipal system, or one that provides water to more than 25 people for at least 60 days per year (regulations vary, so check with your local water department)—you can be fairly certain that the water supply is tested on a regular basis. The frequency of testing depends on the number of people served, and may range from more than once per week to once per month, or even less often. Under these conditions, it’s a good idea to test your water when you move into a new residence to establish a baseline for contaminant levels, if any. Retest every three years unless you have reason to believe that something has changed that could affect the water quality.
If you have a private well, you alone are responsible for the water your family drinks and bathes in. It is recommended to have your water tested by your local health department every six months for bacteria and nitrate. These two tests serve as indicators for other potential types of contamination. That is not to say you should ignore other tests—rather, if either of these tests comes back with poor results, you should also test for additional contaminants. Private wells should be tested regularly for pesticides, herbicides, metals, organic and inorganic chemicals, and volatile compounds. Currently, no laws regulate how often private wells must be tested—meaning you are solely responsible for your family’s water quality. An initial test to establish a baseline, followed by testing at least once per year, is strongly recommended. Keep in mind: one day after testing shows “no contaminants,” your source could still become contaminated.
What Could I Test For?
Coliform bacteria are microorganisms commonly found in the intestinal tracts of humans and other warm-blooded animals, as well as in surface water. Their presence in drinking water suggests contamination from surface or shallow subsurface sources such as cesspool leakage, barnyard runoff, or other pollution. The presence of coliform bacteria indicates that disease-causing (pathogenic) organisms may also enter the drinking water supply if no preventive action is taken. Drinking water should be free of coliforms.
Cysts and viruses are microbiological contaminants usually found in surface water supplies. Giardia lamblia cysts can cause giardiasis, a gastrointestinal illness. Another organism receiving attention is Cryptosporidium, a single-cell parasite about 2–5 microns in diameter. Many surface water supplies contain this pest, which also originates in the intestines of warm-blooded animals.
Nitrate in drinking water can reduce the oxygen-carrying capacity of the blood (cyanosis) when ingested in sufficient amounts by infants under six months old. This condition, known as methemoglobinemia or “blue baby syndrome,” can be life-threatening. Health Canada and the U.S. EPA have established a maximum contaminant level (MCL) for nitrate at 10 mg/L (ppm) measured as nitrogen (N). Unlike coliform or other bacteria, boiling water actually increases the concentration of nitrate, raising the risk to infants. If you have high-nitrate water, you must treat it with an approved method or use another source—boiling will only make it worse.
Lead can leach from older solder joints in copper pipes. As water sits in the pipes, small amounts of lead may dissolve into it. Lead is especially harmful to young children, who absorb it more rapidly. The EPA estimates that more than 40 million U.S. residents use water containing lead levels above recommended limits.
An Easy Way to Test
There are many different water test kits on the market, and not all are equal. Some are designed more for sales demonstrations—for example, “mini softeners,” soap suds tests, or simple precipitation tests that make water problems look dramatic but don’t provide reliable data. Others are service-oriented kits with basic but practical tools for field checks.
For day-to-day monitoring, we recommend having at least these essentials on hand:
TDS meter (total dissolved solids)
Hardness test
Iron test
pH test
Chlorine test
If you live in an area where specific contaminants are more common, you may also want test options for:
Nitrates (common in agricultural regions)
Sulfur/Hydrogen sulfide (causes rotten-egg smell)
Tannins (common near swamps or decaying organic matter)
Bacteria (important for private wells)
These contaminants are not present in every water supply, so it’s best to choose tests that reflect your local water conditions.
Because home kits can only give you a snapshot, we also recommend using a certified water testing laboratory to confirm results or check for a full range of contaminants such as heavy metals, pesticides, and volatile organic compounds.
Recommended Testing Options
Health Canada – Provincial Labs & Public Health Units – Most provinces (Ontario, Alberta, BC, etc.) offer free or low-cost bacterial testing for private wells through local public health units.
ALS Environmental (Canada-wide) – Accredited laboratory offering comprehensive water chemistry and microbiological testing.
SGS Canada – Provides professional water analysis services across Canada.
Canadian DIY Kits (screening use only):
WaterSafe Well Water Test Kit (tests bacteria, nitrate/nitrite, hardness, iron, pH, chlorine, copper, lead, pesticides)
LaMotte Test Kits (reliable professional kits for pH, hardness, iron, chlorine, etc.)
Hach Test Kits (widely used for field testing)
A good approach is:
Use a DIY screening kit or handheld tools (TDS, pH, chlorine, hardness, iron).
Submit samples to a provincial health lab (for bacteria/nitrate) or accredited private lab (ALS, SGS) for full analysis.