The Provincial Government implemented a Regulated Lead Testing Program in 2007. Under this program, the City is required to collect, analyze and submit the results of water samples taken in areas suspected of having lead water service pipes. Under the original program, twice a year, the City collected and reported the results of samples from:
In 2009, the City began developing a Corrosion Control Program as mandated and approved by the Province under the Safe Drinking Water Act.
During the design and implementation of corrosion control treatment (2009–2017), the Province required the City to collect and analyze 20 samples from the water distribution system twice per year.
In 2014, the City implemented corrosion control by adding phosphate to the drinking water treatment process at the City’s four water treatment plants. Phosphate forms a protective coating inside all pipes and household plumbing fixtures, which helps to reduce the potential for lead to enter tap water. Results continue to show a decrease in lead levels.
In March 2017, the City resumed the regulated sampling program. The program included taking samples throughout the year and submitting the results to the Province from at least:
In 2025, the required number of residential and non-residential sampling locations was changed from 55 to 27 locations due to the success of corrosion control treatment and reduced lead levels.
Learn more about the City’s Corrosion Control Plan and read the latest annual update on the Lead in Drinking Water Mitigation Strategy.
Below are results from the past four years and the Pre-Corrosion Control Treatment period.
| Period | Locations | # of Locations | Lead Result – ug/L | % of Samples > 10 ug/L |
||
|---|---|---|---|---|---|---|
| Max. | Min. | Avg. | ||||
|
Round 27 January – December 2025 |
Residential and Non-Residential Taps | 29 | 6.79 | <0.05 | 0.50 | 0 |
| Distribution System | 12 | 0.36 | <0.05 | 0.10 | 0 | |
| Period | Locations | # of Locations | Lead Result – ug/L | % of Samples > 10 ug/L |
||
|---|---|---|---|---|---|---|
| Max. | Min. | Avg. | ||||
|
Round 26 January – December 2024 |
Residential and Non-Residential Taps | 58 | 8.61 | <0.05 | 0.49 | 0 |
| Distribution System | 14 | 0.17 | <0.05 | 0.06 | 0 | |
| Period | Locations | # of Locations | Lead Result – ug/L | % of Samples > 10 ug/L |
||
|---|---|---|---|---|---|---|
| Max. | Min. | Avg. | ||||
|
Round 25 January – December 2023 |
Residential and Non-Residential Taps | 55 | 3.12 | <0.05 | 0.45 | 0 |
| Distribution System | 17 | 0.34 | <0.05 | 0.09 | 0 | |
| Period | Locations | # of Locations | Lead Result – ug/L | % of Samples > 10 ug/L |
||
|---|---|---|---|---|---|---|
| Max. | Min. | Avg. | ||||
|
Round 24 January – December 2022 |
Residential and Non-Residential Taps | 61 | 3.86 | <0.05 | 0.50 | 0 |
| Distribution System | 23 | 0.82 | <0.05 | 0.09 | 0 | |
Rounds 1-12 are results from before the City implemented corrosion control treatment, which started in 2014.
| Period | Locations | # of Locations | Lead Result – ug/L | % of Samples > 10 ug/L |
||
|---|---|---|---|---|---|---|
| Max. | Min. | Avg. | ||||
|
Round 12 June 2013 – October 2013 |
Private Residential Plumbing | |||||
| Private Residential Plumbing (Lead > 11 ug/L) | ||||||
| Non-Private Residential Plumbing | ||||||
| Distribution System | 20 | <0.5 | <0.5 | <0.5 | 0 | |
| Period | Locations | # of Locations | Lead Result – ug/L | % of Samples > 10 ug/L |
||
|---|---|---|---|---|---|---|
| Max. | Min. | Avg. | ||||
|
Round 11 December 2012 – April 2013 |
Private Residential Plumbing | |||||
| Private Residential Plumbing (Lead > 11 ug/L) | ||||||
| Non-Private Residential Plumbing | ||||||
| Distribution System | 20 | 1 | <0.5 | 0.3 | 0 | |
| Period | Locations | # of Locations | Lead Result – ug/L | % of Samples > 10 ug/L |
||
|---|---|---|---|---|---|---|
| Max. | Min. | Avg. | ||||
|
Round 10 June 2012 – October 2012 |
Private Residential Plumbing | |||||
| Private Residential Plumbing (Lead > 11 ug/L) | ||||||
| Non-Private Residential Plumbing | ||||||
| Distribution System | 20 | 8 | <0.5 | 0.9 | 0 | |
| Period | Locations | # of Locations | Lead Result – ug/L | % of Samples > 10 ug/L |
||
|---|---|---|---|---|---|---|
| Max. | Min. | Avg. | ||||
|
Round 9 December 2011 – April 2012 |
Private Residential Plumbing | |||||
| Private Residential Plumbing (Lead > 11 ug/L) | ||||||
| Non-Private Residential Plumbing | ||||||
| Distribution System | 20 | 2 | <0.51 | 0.6 | 0 | |
| Period | Locations | # of Locations | Lead Result – ug/L | % of Samples > 10 ug/L |
||
|---|---|---|---|---|---|---|
| Max. | Min. | Avg. | ||||
|
Round 8 June 2011 – October 2011 |
Private Residential Plumbing | |||||
| Private Residential Plumbing (Lead > 11 ug/L) | ||||||
| Non-Private Residential Plumbing | ||||||
| Distribution System | 20 | 4 | <0.51 | 1.1 | 0 | |
| Period | Locations | # of Locations | Lead Result – ug/L | % of Samples > 10 ug/L |
||
|---|---|---|---|---|---|---|
| Max. | Min. | Avg. | ||||
|
Round 7 December 2010 – April 2011 |
Private Residential Plumbing | |||||
| Private Residential Plumbing (Lead > 11 ug/L) | ||||||
| Non-Private Residential Plumbing | ||||||
| Distribution System | 20 | 0.7 | <0.51 | 0.1 | 0 | |
| Period | Locations | # of Locations | Lead Result – ug/L | % of Samples > 10 ug/L |
||
|---|---|---|---|---|---|---|
| Max. | Min. | Avg. | ||||
|
Round 6 June 2010 – October 2010 |
Private Residential Plumbing | |||||
| Private Residential Plumbing (Lead > 11 ug/L) | ||||||
| Non-Private Residential Plumbing | ||||||
| Distribution System | 20 | 2 | <0.51 | 0.5 | 0 | |
| Period | Locations | # of Locations | Lead Result – ug/L | % of Samples > 10 ug/L |
||
|---|---|---|---|---|---|---|
| Max. | Min. | Avg. | ||||
|
Round 5 December 2009 – April 2010 |
Private Residential Plumbing | |||||
| Private Residential Plumbing (Lead > 11 ug/L) | ||||||
| Non-Private Residential Plumbing | ||||||
| Distribution System | 20 | 5 | <0.51 | 0.7 | 0 | |
| Period | Locations | # of Locations | Lead Result – ug/L | % of Samples > 10 ug/L |
||
|---|---|---|---|---|---|---|
| Max. | Min. | Avg. | ||||
|
Round 4 June 2009 – October 2009 |
Private Residential Plumbing | 100 | 22 | <0.51 | 6.1 | 18 |
| Private Residential Plumbing (Lead > 11 ug/L) | 18 | 22 | 11 | 16.9 | - | |
| Non-Private Residential Plumbing | 10 | 15 | 1.0 | 3.3 | 1 | |
| Distribution System | 21 | 4 | 0 | 1.0 | 0 | |
| Period | Locations | # of Locations | Lead Result – ug/L | % of Samples > 10 ug/L |
||
|---|---|---|---|---|---|---|
| Max. | Min. | Avg. | ||||
|
Round 3 December 2008 – April 2009 |
Private Residential Plumbing | 102 | 38 | <0.51 | 3.9 | 7 |
| Private Residential Plumbing (Lead > 11 ug/L) | 7 | 38 | 11 | 16.9 | - | |
| Non-Private Residential Plumbing | 10 | 4 | <0.51 | 0.7 | 0 | |
| Distribution System | 21 | 4 | <0.51 | 0.8 | 0 | |
| Period | Locations | # of Locations | Lead Result – ug/L | % of Samples > 10 ug/L |
||
|---|---|---|---|---|---|---|
| Max. | Min. | Avg. | ||||
|
Round 2 June 2008 – October 2008 |
Private Residential Plumbing | 100 | 82 | <0.51 | 11.9 | 52 |
| Private Residential Plumbing (Lead > 11 ug/L) | 52 | 82 | 11 | 18.6 | - | |
| Non-Private Residential Plumbing | 10 | 6 | <0.51 | 0.8 | 0 | |
| Distribution System | 21 | 5 | <0.51 | 0.6 | 0 | |
| Period | Locations | # of Locations | Lead Result – ug/L | % of Samples > 10 ug/L |
||
|---|---|---|---|---|---|---|
| Max. | Min. | Avg. | ||||
|
Round 1 December 2007 – April 2008 |
Private Residential Plumbing | 100 | 14 | <0.51 | 3.8 | 6 |
| Private Residential Plumbing (Lead > 11 ug/L) | 6 | 14 | 11 | 12.8 | - | |
| Non-Private Residential Plumbing | 10 | 2 | <0.51 | 0.6 | 0 | |
| Distribution System | 20 | 6 | <0.51 | 0.7 | 0 | |
Ontario Drinking Water Quality Standard for Lead = 10 ug/L (micrograms per litre)
Results with “<” means less than the Method Detection Limit