Public Health and Lead Sampling Protocols for Drinking Water: A Critical Review - Global Drinking Water Management and Conservation - page 215

10.3.3 The Ontario Lead Sampling Protocol

The Ontario provincial regulatory requirements for safe drinking water are in many
ways different from the Federal guidelines and are largely based on the 1999 EU
Report. Ontario Regulation 170/03 under the Safe Drinking Water Act of 2002 sets
out clearly de ned requirements in Schedules 15.1 and 15.2 for sampling protocols

that must be used to determine lead in drinking water in municipal and nonmunicipal
buildings (both residential and nonresidential types). For large and small municipal
residential and nonmunicipal year-round residential properties, the Regulation
requires three samples to be taken at the kitchen tap or the tap that is most commonly
used for drinking water purposes. The first sample is to be taken after a stagnation time

of no less than 30 min but no more than 35 min. This stagnation period will commence
after a period of 5 min of

flushing at the tap. The second sample is to be taken

immediately after the flow rate of

water. A third sample is to be taken immediately after the second sample without
turning off the tap or altering the

first sample without turning off the tap or altering the

first two samples are to be
tested for lead, while the third sample is tested for pH. Apart from obtaining samples
from the tap (source for drinking purposes), three samples have to be taken from a
point in the distribution system. From the distribution point, water is to be

flow rate of water. The

ushed
before the three samples are taken until the quality of water is representative of water in
that part of the distribution system. The first sample from the distribution system is

tested for lead while the second and third samples are tested for alkalinity and pH
respectively. For large and small municipal nonresidential buildings and for seasonal,
large, and small nonmunicipal buildings only one sample is required to be taken
annually from a point in the distribution system or a point in a plumbing systemwhich
is suspected to have elevated lead concentrations .
Samples should be taken every 12 months during the following times: (1)
between December 15 and April 15 and (2) between June 15 and October 15. The
number of samples taken from both plumbing and distribution systems would be
determined by the number of people served by a particular drinking water system
(Table 10.3 shows the number of samples per location).
The stagnation time under the Ontario Safe Drinking Water Act 2002 is based on
a report of the Ontario Drinking Water Advisory Committee, which made recom-
mendations to the Ontario government. The Drinking Water Advisory Committee ' s

report is primarily based on the 1999 EU Report, mentioned above.

10.3.4 The 1999 EU Report

The 1999 EU Report evaluated the performance of several sampling protocols
including:

(1) Random Day Time (RDT): A sample (usually 1 l) taken randomly during
normal working hours from a drinking water tap without any prior flushing.