Conservation Corner: Abandoned wells threaten drinking water

Approximately 2.8 million Ontario residents rely on groundwater. However, rural wells often fail to meet drinking water objectives. Our drinking water is threatened by thousands of old, abandoned wells that provide a direct conduit for bacteria, nitrates, fecal material, chemicals and other contaminant's.

Dr. Goss, of the University of Guelph, has been sampling rural wells for contaminant's for over fifteen years. His surveys of hundreds of wells, found that over 50% of wells failed to meet Ontario drinking water objectives. In the vast majority of cases, bacterial contamination was the culprit. Fecal bacteria, such as E. coli, are linked to gastrointestinal illness and in severe cases death. Approximately 20% of the wells tested positive for Clostridium perfringens, which indicates fecal contamination of animal origin. The source of the other bacteria contaminant's? To quote Pogo, 'I have seen the enemy, and he is us'.

Normally water slowly filters through into aquifers over months or years. This is key because studies have shown fecal bacteria can survive over 6 months. The closer wells are to contamination sources the more likely they are to fail. Manure piles, septic systems, leaky fuel tanks, fertilizer and pesticide applications are potential contamination sources. Trouble with water contamination comes from three things; a source of contaminant's, a route of entry to water and exposure.

Ironically, people well often spend thousands on a new well, but do not protect that investment by properly decommissioning the old one.

Ontario Groundwater Association, which includes well drillers, engineers and scientists, estimates there are over 100,000 old wells in Ontario.

Although the MOE legally requires abandoned wells to be decommissioned, they have no way of knowing whether old wells are sealed unless a complaint is received.

A MOE licensed well contractor must decommission wells. Plugging the well involves the injection of cement or bentonite clay into the well shaft. Typically costs range from $500 to $3000. Costs can vary quite widely for the same well, so shop around. Landowners can apply for grants to help offset the cost. Farmers can access grants of 50% through the Environmental Farm Plan, and all landowners can apply to the NVCAs Healthy Waters Program.

You can book a site visit with the Well Aware program and a skilled person will go over how to keep your well providing safe, clean water.

The program is committed to providing local rural residents with the knowledge they need to help them manage their wells properly and understand their responsibilities as well owners.