Well water safety:  is your well water safe?

Manitoba has an abundance of good quality groundwater. However, under certain conditions, bacteria and other tiny organisms may be introduced into the groundwater and wells. Most of the time, the presence of these "germs" do not cause serious illness. In some cases, however, people can become very ill from drinking contaminated water. E. coli 0157 is one type of bacteria that can cause severe disease as well as death. (Although water has never been identified as a cause of E. coli 0157 infection in Manitoba, the large outbreak in Ontario has alerted all Canadians to this possibility.) 

To minimize the risk of illnesses that can be caused by contaminated water, all well users should check that their well is safe from sources of contamination. In addition, testing should be carried out regularly.

It is recommended that a water sample be submitted for bacterial analysis at least once a year and after well servicing, to ensure that the water is safe for drinking. Well water should also be tested whenever a change in taste, odour or colour is noticed, if you suspect illness may be caused by water, or when the risk of contamination increases due to changes in environmental conditions. These may include flooding, a change in surrounding land use, or after an extended dry spell.

Some of the most commonly asked questions related to private wells are:

1. Where can I get my water tested?

   Contact an accredited water-testing laboratory. These laboratories are listed in your yellow pages under Laboratories – Testing. They will provide you with a testing kit and proper instructions for sampling. Bottles for water testing may be obtained form the labs as well as the offices of the Manitoba Water Services Board and Manitoba Conservation. 

2. What do the results of this test tell me?

   Bacteriological tests look for the presence of bacteria that indicate contamination, such as total coliforms, fecal coliforms and/or E. coli. Coliform bacteria occur naturally in soil and the intestines of humans and animals. Thus, their presence in water may indicate fecal contamination. E. coli is one kind of fecal coliform that is present in the intestines of humans and animals. Most E. coli do not cause human illness. E. coli 0157 is one specific type of E. coli.

   When a sample is reported as safe to drink, it should mean that coliform bacteria were not found in the sample. A report may include the actual numbers of bacteria found. The absence of coliform bacteria indicates the absence of E. coli bacteria and other disease-causing organisms. It means that the water should be suitable for drinking and food preparation uses.

   When a sample is reported unsafe to drink or in need of re-testing, it means that coliform bacteria were found in your sample. Their presence in the sample may indicate that the well water is contaminated.

3. What should I do if the test results indicate the presence of bacteria?

   The presence of coliform bacteria indicates that the water could be unsafe to drink. As a precautionary measure, the water should be boiled for two minutes prior to consumption. A second sample should be taken to confirm your first unsafe result. Be sure to use the proper sampling procedure to avoid a test error (contamination). If the second sample result confirms the unsafe result, you should proceed to disinfect your well. Information about well disinfection is available in a separate bulletin entitles "Private Well Disinfection" available from the contacts identified at the end of this document.

4. How can I prevent contamination of the well?

There are several possible causes for contamination of wells. In addition to annual visual inspection, a number of basic steps should be undertaken to prevent potential problem areas.

Drainage problems around wells:

If runoff water accumulates around the well, it will often seep downward through the coarse soil around the well casing and enter the groundwater. To prevent this problem, the area around the well should be built up with good clay soil and sloped away from the well. Pipeline trenches to the well should also be mounded with dirt or clay. In addition, the well casing should extend upward above the ground to allow for proper sloping of the site.

Well lids or caps: The well lids or caps should be tight to shed water and prevent any bugs, mice or other creatures from entering your well.

Well casing/cribbing: Many small creatures can enter a well through small openings if they are not properly sealed above water level. Should you notice heavy rusting or cracking, corrective steps should be taken. Openings for electrical conduits entering the well should be properly sealed.

Trees: Tree roots can enter a well, seeking moisture through cracks or joints, thus giving dirt and bacteria a pathway to enter the well. Ensure that the trees are at least 15m (50 feet) from your well.

Abandoned wells: Abandoned or unused wells are a major source of contamination and are a hazard to public safety. They should be properly sealed.

Proximity to septic fields, etc.: If your well is in close proximity to septic tanks/fields, barns, feed lots, rock outcropping, sink holes, quarries, etc., there is a higher possibility of contamination of your well water.

For further information on any of the above, please contact the nearest office of the Manitoba Water Services Board or Manitoba Conservation.

The Manitoba Water Services Board
Brandon   204-726-6079
Fax 204-726-6290

Dauphin 204-622-2116
Fax 204-622-2298

Beasejour 204-268-6059
Fax 204-268-6060

Manitoba Conservation
Winnipeg 204-945-7069
Fax 204-948-2420

Brandon 204-726-6060
Fax 204-726-6567

Virden 204-748-2321
Fax 204-748-2388

Steinbach 204-346-6061
Fax 204-326-2472

Selkirk 204-785-5033
Fax 204-785-5024

Lac du Bonnet 204-345-8647
Fax 204-345-8609

Flin Flon 204-687-1625
Fax 204-687-1623

The Pas 204-627-8361
Fax 204-623-1773

Dauphin 204-622-2126
Fax 204-622-2306

Swan River 204-734-3436
Fax 204-734-5615

Winkler 204-325-1754
Fax 204-325-1758

Portage 204-239-3188
Fax 204-239-3185

Thompson 204-677-6704
Fax 204-677-6652