ACTION ALERT: Citizen Comments Needed
On Canadian Drinking Water Guidelines
EBR: Proposal to revise the Canadian Drinking Water
Guideline for Turbidity
EBR Registry Number:
PA02E0006 Type of Posting: Policy Ministry: Environment
Status of Posting: Proposal Date Proposal Loaded: 2002/06/21
Comment Period: 119 day(s) Written
submissions may be made between June
21, 2002 and October 18, 2002.
Proposal to revise the Canadian
Drinking Water Guideline for Turbidity
The primary purpose of Ontario Drinking
Water Standards is to protect public health. Most Ontario
Drinking Water Standards are adopted from the
Guidelines for Canadian Drinking Water Quality.
The Guidelines for Canadian Drinking
Water Quality are established via a formal Federal-Provincial-Territorial
process with the participation of Health Canada,
Environment Canada and each of the provinces and territories.
These Guidelines are established/revised as necessary
by the Federal-Provincial-Territorial Subcommittee on
Drinking Water (DWS).
Turbidity has been reassessed by Health
and the DWS. New criteria based on ensuring optimal
performance by various filtration technologies are being
proposed. The proposed revised Canadian Drinking Water
Guideline (CDWG) for turbidity is 0.1 to 1 NTU depending
on filtration method.
A National Consultation on the proposed
CDWG has recently been initiated.
The consultation will run until October
Purpose of the Proposal:
Health Canada and the Federal-Provincial-Territorial
Subcommittee on Drinking Water propose revising the
existing Canadian Drinking Water Guideline for turbidity
of 1 Nephelometric Turbidity Unit (NTU) as follows:
(1) For chemically assisted filtration,
(a) When the monthly average of daily
source water turbidity is greater than or equal to 1.5
NTU, the filtered water turbidity is to be less than
0.3 NTU in at least 95% of the measurements made each
calendar month; not exceed 0.3 NTU for more than 12
consecutive hours; and not exceed 1.0 NTU at any time.
(b) When the monthly average of daily
source water turbidity is less than 1.5 NTU, the filtered
water turbidity is to be less than 0.2 NTU in at least
95% of the measurements made each calendar month; not
exceed 0.2 NTU for more than 12 consecutive hours; and
not exceed 1.0 NTU at any time.
(2) For slow sand or diatomaceous earth
filtration, the filtered water turbidity is to be less
than or equal to 1.0 NTU in at least 95% of the measurements
made each calendar month; and not exceed 3.0 NTU at
(3) For membrane filtration, the filtered
water turbidity is to be less than or equal to 0.1 NTU
in at least 95% of the measurements made each calendar
month; and not exceed 0.3 NTU at any time.
Excessive turbidity has often been
associated with unacceptable tastes and odours. Turbidity
in excess of 5 NTU becomes visually apparent and may
be objected to by consumers. Also, turbidity higher
than 5 NTU in distribution systems or at the tap generally
serves to signal deteriorating water quality such as
local corrosion, scaling and/or the growth of nuisance
bacteria. Accordingly, an aesthetic objective of 5 NTU
is currently in effect for water within distribution
systems. This aesthetic objective will remain the same
under the proposed revision.
Canadian Drinking Water Guidelines
are adopted as guidelines or standards by the Provinces
and Territories, including Ontario. Upon its finalization,
the proposed revised CDWG for turbidity would be adopted
as an Ontario Drinking Water Standard (ODWS).
Note that the proposed CDWG allows
for measuring the turbidity of combined filter effluents.
Ontario proposes that, if adopted, the corresponding
ODWS would be applied to each individual filter, as
per the current ODWS. This is advantageous from both
operational and health protection standpoints.
Other Public Consultation:
Subcommittee on Drinking Water (DWS) is conducting a
national public consultation on the proposed revised
turbidity CDWG, ending October 18, 2002. Comments received
through this Ontario EBR consultation will be forwarded
to the DWS as input to the national consultation.
Comments may be submitted by e-mail
Comments should be directed to the
following Contact Person:
Adam Socha Standards Development Branch
125 Resources Road Toronto, Ontario, M9P 3V6 PHONE:
(416) 327-9854 FAX:
Some Government offices have additional
information on this proposal for viewing.
These are listed below:
Standards Development Branch 40 St.
Clair Avenue West
7th floor, Toronto, Ontario, M4V 1M2
PHONE: (416) 327-5519 FAX: (416) 327-2936
Additional material in support of this
notice is available by clicking the following hyperlink(s):
All comments will be considered as
part of the decision-making by the Ministry if they:
(a) are submitted in writing; (b) reference the EBR
Registry number; and (c) are received by the Contact
person within the specified comment period.
** No acknowledgment or individual
response will be provided to those who comment. All
comments & submissions received will become part
of the public record. **