Highway 6 Well Water Odour Complaint

The MECP will be providing all updates to the Township which will be shared on this webpage. If you have new information to provide to the MECP please send it to Lynnette.Armour@ontario.ca.

July 24, 2023 Update

The Ministry of the Environment, Conservation and Parks takes citizens’ concerns seriously and follows up on all complaints to ensure human health and the environment are protected.

Sample Results

On July 19, 2023, the ministry received the analytical results from samples taken on July 11, 2023. The results show that odour-causing organics were detected in untreated well water.
- The testing carried out at the ministry laboratory found low levels of methional (1.2 µg/L), dimethyl trisulfide (3.4 µg/L) and dimethyl disulphide (16 µg/L).
- These substances are associated with natural bacterial activity in the vicinity of groundwater sources containing sulphides.
- The substances that were detected in the well water are likely the result of bacteria present in the well that feed on sulphur compounds and sources of carbon (e.g., biofilms) which release these substances as by-products.
- Sulfur compounds and bacteria are quite common in the environment and may be naturally present in groundwater in Ontario.
The odour reported by the homeowner is consistent with our knowledge about these compounds as all three have very low odour thresholds for detection.
- Sulfur is a naturally occurring element, Sources of sulphur compounds include decaying organic matter or chemical reactions with sulfur-containing minerals in soil and rock.
- Odour-causing organics can be produced when microbes and bacteria breakdown sulphur containing compounds as well as algae and fungus. The presence of these compounds in water causes a bad odour or taste in tap water.
There is no Ontario Drinking Water Standard or Guideline for Canadian Drinking Water Quality for the odour-causing organics detected in the samples.
- According to Health Canada, no jurisdiction has developed health-based drinking water quality guidelines/standards for these substances as they are mainly associated with aesthetic issues since even a low level would make the water unpalatable.
- In a municipal drinking water system, these substances would not be a cause of concern as treatment such as granular activated carbon (GAC), chlorination, and aeration can be used to effectively remove sulphides.
- At the residential treatment system level, GAC or reverse osmosis can remove these substances resulting in palatable water.
The geology of the area has also been reviewed. The impermeable nature and thickness of the ground covering the water table (the depth that the wells are drawing water from) makes it unlikely that any chemical spills or ditch drainage along Highway 6 can migrate into the bedrock aquifer.
The Ministry of the Environment, Conservation and Parks does not regulate drinking water from private wells.
A properly maintained well along with an appropriate treatment technology will eliminate the type of odour issues in Puslinch.
- There are several well maintenance manuals that can be used by private well owners to ensure drinking water safety, including guidance from Health Canada, and Public Health Ontario.
- It is the responsibility of the private well owners to investigate and install treatment for water quality issues associated with private drinking water wells.
- The homeowners in Puslinch experiencing taste and odour issues with their wells should review these documents but may also consider engaging a water treatment professional who can address their specific situation.
- If the well owner identifies a health-related issue, they can contact the Wellington-Dufferin-Guelph Public Health to determine the next steps and to answer any questions related to whether the private well water is safe.

July 21, 2023 Update

The Ministry of Environment, Conservation and Parks (ministry) takes citizens’ concerns seriously and follows up on all complaints to ensure human health and the environment are protected.

Sample Results

On July 19, 2023, the ministry received the analytical results from samples taken on July 11, 2023. The results show odour causing organics were detected in untreated well water.
Odour causing organics can be produced when microbes and bacteria breakdown sulfur containing compounds as well as algae and fungus. The presence of these compounds in water causes a bad odour or taste in tap water.
There is no Ontario Drinking Water Standard or Guideline for Canadian Drinking Water Quality for the odour causing organics detected in the samples.
The geology of the area has also been reviewed. The impermeable nature and thickness of the ground covering the water table (the depth that the wells are drawing water from) makes it unlikely that any chemical spills or ditch drainage along Highway 6 can migrate into the bedrock aquifer.
The water supplying the wells is affected by the quality of source water that recharges the bedrock aquifer. The ministry recommends residents contact a water treatment specialist to discuss treatment options if they are still experiencing odours from their private wells.
- The Ministry of the Environment, Conservation and Parks does not regulate drinking water from private wells.
- It is the responsibility of the private well owners to investigate and install treatment for water quality issues associated with private drinking water wells.
- If the well owner identifies a health-related issue, they can contact the Wellington-Dufferin-Guelph Public Health to determine next steps and to answer any questions related to whether the private well water is safe.

July 19, 2023 Update

The Ministry of Environment, Conservation and Parks (ministry) takes citizens’ concerns seriously and follows up on all complaints to ensure human health and the environment are protected.

The ministry is looking into potential sources that may be causing the private well water odours in the Puslinch area. Ministry staff attended the area on July 11, 2023, to inspect for a source of the odours and did not note any spills in the area.

Samples were taken from four private water wells and have been sent to the ministry laboratory for analysis.
The samples have been analyzed. The results are currently being reviewed by a ministry Hydrogeologist and will be shared with the property owners by the end of day on July 20, 2023.
In addition, a ministry Hydrogeologist has reviewed the geology of the area and has advised that the cause of the odour is unlikely to be from a spill in the immediate area due to the impermeable nature and thickness of ground covering the water table (the depth that the wells are drawing water from).

Odours in water can be naturally occurring, however the ministry has not made any conclusions about the cause at this time.

The ministry will continue to communicate with the Township of Puslinch and impacted residents and share information regarding the source of the odour as soon as it becomes available.

The ministry is encouraging residents in the area who may be experiencing odours from their private wells to notify the ministry.
- Updates on the ministry’s actions will be provided to the Township and the Township will update their website link with the latest information.
- Residents may also contact Wellington-Dufferin-Guelph Public Health if they have questions relating to whether water from their private well should be consumed, until a cause has been identified.

The ministry regulates the construction and maintenance of private drinking water wells. It is the responsibility of the private well owners to investigate and install treatment for water quality issues associated with private drinking water wells. If the well owner identifies a health-related issue, the ministry will aid the homeowner in identifying the contributing factors.

As of 4:00 pm on July 19, 2023, the ministry has received the analytical results for the samples taken on July 11, 2023. The results are currently being reviewed by a ministry Hydrogeologist and will be shared with the property owners by the end of day, July 20, 2023.

July 18, 2023 Update

As of 2:30 pm on July 18, 2023, samples taken on July 11, 2023, continue to be analyzed for taste and odour compounds in addition to open characterization to identify potential causes of the odour noted in the well water. Additional updates will be provided when new information becomes available.

July 17, 2023 Update

As of 2:30 pm on July 17, 2023, samples taken on July 11, 2023, continue to be analyzed for taste and odour compounds in addition to open characterization to identify potential causes of the odour noted in the well water. Additional updates will be provided when new information becomes available.

July 14, 2023 Update

The Ministry of Environment, Conservation and Parks (ministry) takes citizens’ concerns seriously and follows up on all complaints to ensure human health and the environment are protected.
The ministry is looking into potential sources that may be causing the private well water odours in the Puslinch area. Ministry staff attended the area on July 11, 2023, to inspect for a source of the odours and did not note any spills in the area.
Samples were taken from four private water wells and have been sent to the ministry laboratory for analysis. The samples are being analyzed to help determine the source of the odour. The ministry has prioritized the sampling and expects to have results by early next week.
- Results will be reviewed and shared with the property owners as soon as they are available.
In addition, a ministry Hydrogeologist has reviewed the geology of the area and has advised that the cause of the odour is unlikely to be from a spill in the immediate area due to the impermeable nature and thickness of ground covering the water table (the depth that the wells are drawing water from).
Odours in water can be naturally occurring, however the ministry has not made any conclusions about the cause at this time.
The ministry will continue to communicate with the Township of Puslinch and impacted residents and share information regarding the source of the odour as soon as it becomes available.
The ministry is encouraging residents in the area who may be experiencing odours from their private wells to notify the ministry.
- Updates on the ministry’s actions will be provided to the Township and the Township will update their website link with the latest information.
- Residents may also contact Wellington-Dufferin-Guelph Public Health if they have questions relating to whether water from their private well should be consumed, until a cause has been identified.
As of 2:30 pm on July 14, 2023, samples taken on July 11, 2023, continue to be analyzed for taste and odour compounds in addition to open characterization to identify potential causes of the odour noted in the well water. Additional updates will be provided when new information becomes available.
The ministry regulates the construction and maintenance of private drinking water wells. It is the responsibility of the private well owners to investigate and install treatment for water quality issues associated with private drinking water wells. If the well owner identifies a health-related issue, the ministry will aid the homeowner in identifying the contributing factors.

July 12, 2023 Update

The Ministry of Environment, Conservation and Parks (ministry) takes citizens’ concerns seriously and follows up on all complaints to ensure human health and the environment are protected.
The ministry is looking into potential sources that may be causing the private well water odours in the Puslinch area. Ministry staff attended the area on July 11, 2023, to inspect for a source of the odours and did not note any spills in the area.
Samples were taken from four private water wells and have been sent to the ministry lab for analysis. The samples are being analyzed for taste and odour compounds. The ministry has prioritized the sampling and expects to have results by early next week.
- Results will be reviewed and shared with the property owners as soon as they are available.
In addition, a ministry Hydrogeologist has reviewed the geology of the area and has advised that the cause of the odour is unlikely to be from a spill in the immediate area due to the impermeable nature and thickness of ground covering the water table (the depth that the wells are drawing water from). Odours in water can be naturally occurring, however the ministry has not made any conclusions about the cause at this time.
The ministry will continue to communicate with the Township and impacted residents and share information as soon as it becomes available regarding the source of the odour.
Residents can contact Wellington-Dufferin-Guelph Public Health at (519) 822-2715 if they have questions relating to whether water from their private well should be consumed until a cause has been identified.