After such a wet spring, especially in flood-stricken Manitoba, many farmers are concerned about the safety of their well water. They’re right to be worried. With all the surface water swirling about in farmyards, it’s not difficult to imagine that some domestic wells might have been compromised.
But flooding isn’t the only cause of well contamination. Other culprits include shallow wells, wells built in porous materials such as sand or gravel, and wells located in pits and low areas where surface water can collect and sit. Wells with unsealed casings, casings that do not extend at least 30 cm (12 inches) or more above ground, or casings that are rusted out in spots are also vulnerable. At risk, too, are wells located near septic tanks or fields, barns, feedlots, or near old, abandoned wells that have not been properly sealed.
“Poorly constructed, old, shallow wells, and those located in depressions with water pooling around are more vulnerable to contamination,” says Gilbert Bushati, senior regional drinking water officer with Manitoba Water Stewardship. Wells that are overtopped with flood water are a particular source of concern, he adds. Sometimes wells may look normal, but there may be other warning signs of contamination, such as a change in water colour, clarity, smell, or taste.
Once the floods recede, the fastest way to ensure your drinking water is safe is to test it, something experts say should be done yearly, whether you’ve had a flood or not. A well water test called a total coliform or TC test looks for the presence of coliform bacteria, especially E. coli, a type of fecal coliform bacteria commonly found in the intestines of animals and humans. The presence of E. coli in water is a strong indication of recent sewage or animal waste contamination.
“Our primary concern is human or animal-related fecal contamination of well water as shown by the presence of E. coli,” says Bushati. “In very general terms, samples that fail testing for total coliform show that the well is vulnerable to contamination, whereas the presence of E. coli means the well is contaminated with fecal bacteria.”
Drinking water should contain zero total coliform bacteria per 100 ml, and there are labs in every province that can do this test.
Paul and Sally Calcott, who operate an 800-acre cattle and grain farm in southwest Manitoba, always check their well water annually. And, until this flood-ridden year, they were used to seeing an all-clear on their test.
“It’s the first time we had a failure. I was surprised because we have always passed,” says Sally, who received the lab results back at the end of May. “This time we had a total coliform reading of three, but our E. coli was a pass, so that’s good. We didn’t actually flood around the house, but there was a lot of flooding on the other side of the road. We did have some well repairs and some work on our pressure tank earlier this year, so we think that might have stirred things up.”
Receiving a “fail” on a water test does not necessarily mean you or your family members will get sick. There are ways to correct water quality and safety deficiencies, and help and advice are available when a sample does not make the grade.
“Different people have varying degrees of resistance,” said Bushati. “Any presence of total coliform or E. coli in a water sample is technically a failed sample, though consuming that water may or may not result in sickness,” he explains. “Some species of E. coli can be harmful. However, there may be other organisms in contaminated well water that are cause for concern.”
Sometimes well water might fail a TC test simply because of the way the sample was collected. You may be getting a one, two or three on your total coliform reading because of how the sample was taken,” says Bob Kitlar, well water specialist with Winnipeg’s ALS Environmental, a division of ALS Group that provides a full range of environmental testing services. “The best place to take your sample is actually from an outside tap, rather than inside the house.”
Wells that have been overtopped with flood water may have suffered structural damage, in addition to the influx of bacteria and other types of contaminant. People living in a flooded area are advised to boil their well water until floods recede and testing confirms that the water is safe to drink.
You’ll also have to boil your well water if it fails the TC test. Boiling is simple, quick and very effective. It’s also cheap and doesn’t involve any costly apparatus. “It’s a full, rolling boil, for a minute,” says Kitlar. “That’s a temperature of 212º F, or 100º C, and it kills most things, such as viruses, bacteria and protozoa (another group of microorganisms that can cause human illness).”
Effective boiling means putting water in a pot, or an electric kettle without an automatic shut-off, and bringing it to a rolling boil for one minute. At elevations over 2,000 metres, water boils at a slightly lower temperature and should be boiled for at least two minutes. The water is then cooled, poured into a clean container and refrigerated until you are ready to use it.
If you still have a problem, even after re-sampling, you could look at devices to help clean up your water. Chlorinators and iodinators can kill most disease-carrying organisms, while an ultra violet (UV) device can combat bacteria and viruses. Ceramic or glass fibre filters remove bacteria and protozoa from mildly contaminated waters. Distillers can reduce chemicals in water, and ozonators can kill pathogens.
Shock chlorination is another do-it-yourself procedure that can be used to control many kinds of bacteria in wells, especially iron bacteria that create a reddish-brown slime as well as an unpleasant taste and odour.
The Calcotts, like many other farmers across the prairies, don’t take any chances when it comes to the safety of their drinking water. This time, they followed the boiled water advisory received along with their TC test results and disinfected their well with a shock chlorination treatment.