Ontario Regulated Lead Testing Program

In 2007, the Provincial Government 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 Province under the Safe Drinking Water Act.

During the design and implementation of corrosion control (2009-2017), the Province 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 the regulated sampling program, which includes taking samples throughout the year from:

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

These results are submitted to the Ontario Ministry of the Environment, Conservation and Parks (MECP).

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