In 2007, the Ontario Ministry of the Environment and Climate Change (MOECC) implemented a Regulated Lead Testing Program under which Toronto Water was 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, Toronto Water collected and reported the results of samples from:

  • 100 residential water service connections
  • 20 connections from within the distribution system
  • 10 non-residential water service connections

In 2009, Toronto Water began developing a Corrosion Control Program as mandated and approved by the MOECC under the Safe Drinking Water Act.

During the design and implementation of corrosion control (2009-2017), the MOECC required the City to collect and analyse 20 samples from the water distribution system twice a year. Results are shown below.

In 2014, the City implemented corrosion control by adding phosphate to the drinking water treatment process at the 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. Recent results indicate a reduction in lead levels.

In March 2017, Toronto Water resumed a MOECC-regulated sampling program, which includes taking samples throughout the year from:

  • 55 residential and non-residential tap locations
  • 10 distribution system locations

Regulated Test Results

 

Period Locations # of
Locations
Lead Result
– ug/L
% of Samples
> 10 ug/L
Max. Min. Avg.

Round 19

January

December 2017

Residential and Non-Residential Taps  55  73.2  <0.05  2.8  2
Distribution System  10  0.85 <0.05  0.28 0

 

Period Locations # of
Locations
Lead Result
– ug/L
% of Samples
> 10 ug/L
Max. Min. Avg.

Round 18

June 2016

October 2016

Private Residential Plumbing
Private Residential Plumbing – (Lead > 11 ug/L)
Non-Private Residential Plumbing
Distribution System  20  1.2 <0.05  0.3 0

Round 17

December 2015

April 2016

Private Residential Plumbing
Private Residential Plumbing – (Lead > 11 ug/L)
Non-Private Residential Plumbing
Distribution System 20 0.65 0.06 0.2 0

 

Period Locations # of
Locations
Lead Result
– ug/L
% of Samples
> 10 ug/L
Max. Min. Avg.

Round 16

June 2015

October 2015

Private Residential Plumbing
Private Residential Plumbing – (Lead > 11 ug/L)
Non-Private Residential Plumbing
Distribution System  20  1.2 0.06  0.3 0

Round 15

December 2014

April 2015

Private Residential Plumbing
Private Residential Plumbing – (Lead > 11 ug/L)
Non-Private Residential Plumbing
Distribution System 20 104 0 7.9 3

Round 14

June 2014

October 2014

Private Residential Plumbing
Private Residential Plumbing – (Lead > 11 ug/L)
Non-Private Residential Plumbing
Distribution System 20 0.96 <0.05 0.3 0

Round 13

December 2013

April 2014

Private Residential Plumbing
Private Residential Plumbing – (Lead > 11 ug/L)
Non-Private Residential Plumbing
Distribution System 20 1.9 0.07 0.6 0

 

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

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

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

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

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

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

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

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

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

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