2023 Shoal Lake water quality test results

Our staff test Shoal Lake and the intake at the west end of Indian Bay (where the water enters the aqueduct) as part of our routine water quality testing program.

For more information on Winnipeg's drinking water and our impact on Shoal Lake, visit the web page on Shoal Lake - Our Water Source.

Testing

We take samples at the intake every week during the open water season and every two weeks during the rest of the year. We also take samples from the Shoal Lake watershed from May to October. We test the intake samples for:

• routine water chemistry
• metals
• disinfection by-products
• bacteria and protozoa
• pesticides, herbicides and PCBs

By taking these samples, we track seasonal changes in water quality and determine the effects (if any) of human activity within the Shoal Lake watershed.

Water entering the aqueduct intake passes through screens before being treated by chlorine on a periodic basis for slime and Zebra mussel control. The aqueduct brings water to Deacon Reservoir before entering the Water Treatment Plant. There, we test both the raw and treated water before the water is distributed to Winnipeg homes and businesses.

Test results are from January 1 to December 31, 2023

What is being measured	How it's measured	Shoal Lake average	Shoal Lake range
Miscellaneous
Carbon, Dissolved Organic	parts per million	8.8	7.3 to 10.1
Carbon, Total Organic	parts per million	8.9	7.0 to 11.0
Chlorophyll-a	parts per billion	4.3	<1.0 to 8.0
Colour, Apparent	TCU	15.6	12.0 to 20.0
Colour, True	TCU	9.7	7.5 to 12.0
Conductivity	microsiemens per centimetre	157	145 to 174
Odour	units	90	75 to 150
pH	units	8.05	7.59 to 8.70
Plankton (algae) count	cells/mL	14,257	<100 to 62,830
Solids, Total	parts per million	105	98 to 114
Solids, Total Dissolved	parts per million	87	68 to 104
Temperature	degrees Celcius	11.2	2.4 to 24.0
Turbidity (clearness)	NTU	0.87	0.18 to 3.03
Anions and Nutrients
Alkalinity, Total	parts per million as calcium carbonate	75.5	67.8 to 82.9
Hardness, Total	parts per million as calcium carbonate	78.6	70.2 to 95.2
Chloride	parts per million	2.2	1.5 to 2.8
Fluoride	parts per million	0.07	0.07 to 0.08
Nitrate Nitrogen	parts per million	0.042	0.011 to 0.082
Perchlorate	parts per billion	<0.20	<0.20 to <0.20
Phosphorus, Total Reactive	parts per million	0.0023	<0.0010 to 0.0118
Phosphorus, Total	parts per million	<0.02	<0.02 to 0.04
Sulphate	parts per million	<0.4	<0.4 to 0.4
Total Kjeldahl Nitrogen (TKN)	parts per million	0.52	0.45 to 0.63
Bacteria
Escherichia Coli	MPN per 100 mL	2	<1 to 8
Total Coliforms	MPN per 100 mL	94	<1 to >200
Disinfection By-Products
Haloacetic acids	parts per billion	<1.2	<1.2 to <1.2
Trihalomethanes	parts per billion	<2.7	<2.7 to <2.7
Enteric Protozoa
Cryptosporidium	oocysts per 100 L	<0.1	<0.1 to <0.1
Giardia	cysts per 100 L	<0.1	<0.1 to <0.1
Pesticides
Alachlor	parts per billion	<0.10	<0.10 to <0.10
Aldrin	parts per billion	<0.0080	<0.0080 to <0.0080
alpha-HCH	parts per billion	<0.0080	<0.0080 to <0.0080
alpha-Chlordane	parts per billion	<0.0080	<0.0080 to <0.0080
alpha-Endosulfan	parts per billion	<0.0070	<0.0070 to <0.0070
Atrazine	parts per billion	<0.10	<0.10 to <0.10
Azinphos-methyl	parts per billion	<0.10	<0.10 to <0.10
beta-HCH	parts per billion	<0.0080	<0.0080 to <0.0080
beta-Endosulfan	parts per billion	<0.0070	<0.0070 to <0.0070
Carbaryl	parts per billion	<0.20	<0.20 to <0.20
Carbofuran	parts per billion	<0.20	<0.20 to <0.20
Chlorpyrifos	parts per billion	<0.10	<0.10 to <0.10
delta-HCH	parts per billion	<0.0080	<0.0080 to <0.0080
Diazinon	parts per billion	<0.10	<0.10 to <0.10
Diclofop-methyl	parts per billion	<0.10	<0.10 to <0.10
Dieldrin	parts per billion	<0.0080	<0.0080 to <0.0080
Dimethoate	parts per billion	<0.10	<0.10 to <0.10
Endrin	parts per billion	<0.010	<0.010 to <0.010
Eptam	parts per billion	<0.20	<0.20 to <0.20
gamma-Chlordane	parts per billion	<0.0080	<0.0080 to <0.0080
Heptachlor	parts per billion	<0.0080	<0.0080 to <0.0080
Heptachlor Epoxide	parts per billion	<0.0080	<0.0080 to <0.0080
Lindane (gamma-HCH)	parts per billion	<0.0080	<0.0080 to <0.0080
Malathion	parts per billion	<0.10	<0.10 to <0.10
Methoxychlor	parts per billion	<0.0080	<0.0080 to <0.0080
Methyl Parathion	parts per billion	<0.10	<0.10 to <0.10
Metribuzin	parts per billion	<0.10	<0.10 to <0.10
Mirex	parts per billion	<0.0080	<0.0080 to <0.0080
o,p-DDD	parts per billion	<0.0040	<0.0040 to <0.0040
o,p-DDE	parts per billion	<0.0040	<0.0040 to <0.0040
o,p-DDT	parts per billion	<0.0040	<0.0040 to <0.0040
p,p-DDD	parts per billion	<0.0040	<0.0040 to <0.0040
p,p-DDE	parts per billion	<0.0040	<0.0040 to <0.0040
p,p-DDT	parts per billion	<0.0040	<0.0040 to <0.0040
Parathion	parts per billion	<0.10	<0.10 to <0.10
Propaclor	parts per billion	<0.20	<0.20 to <0.20
Propanil	parts per billion	<0.20	<0.20 to <0.20
Propoxur	parts per billion	<0.20	<0.20 to <0.20
Simazine	parts per billion	<0.10	<0.10 to <0.10
Terbufos	parts per billion	<0.10	<0.10 to <0.10
Triallate	parts per billion	<0.10	<0.10 to <0.10
Trichlopyr	parts per billion	<0.50	<0.050 to <0.50
Trifluralin	parts per billion	<0.10	<0.10 to <0.10
Polychlorinated Biphenyls
Arochlor 1016	parts per billion	<0.020	<0.020 to <0.020
Arochlor 1221	parts per billion	<0.020	<0.020 to <0.020
Arochlor 1232	parts per billion	<0.020	<0.020 to <0.020
Arochlor 1242	parts per billion	<0.020	<0.020 to <0.020
Arochlor 1248	parts per billion	<0.020	<0.020 to <0.020
Arochlor 1254	parts per billion	<0.020	<0.020 to <0.020
Arochlor 1260	parts per billion	<0.020	<0.020 to <0.020
Phenoxy Acid Herbicides
2,4,5-T	parts per billion	<0.50	<0.050 to <0.50
2,4,5-TP	parts per billion	<0.50	<0.050 to <0.50
2,4-D	parts per billion	<0.50	<0.050 to <0.50
2,4-DB	parts per billion	<0.50	<0.050 to <0.50
2,4-DP	parts per billion	<0.50	<0.050 to <0.50
Bromoxynil	parts per billion	<0.50	<0.050 to <0.50
Dicamba	parts per billion	<1.0	<0.010 to <1.0
Dinoseb	parts per billion	<0.50	<0.050 to <0.50
MCPA	parts per billion	<0.50	<0.050 to <0.50
MCPB	parts per billion	<0.50	<0.050 to <0.50
Mecoprop	parts per billion	<0.50	<0.050 to <0.50
Picloram	parts per billion	<1.0	<0.10 to <1.0
Total Metals
Aluminum	parts per million	0.00467	0.00097 to 0.01358
Antimony	parts per million	0.000071	<0.000025 to 0.000168
Arsenic	parts per million	0.000907	0.000636 to 0.001104
Boron	parts per million	0.01079	0.00788 to 0.01329
Cadmium	parts per million	<0.000007	<0.000007 to <0.000007
Calcium	parts per million	19.890	17.303 to 24.924
Chromium	parts per million	<0.00004	<0.00004 to 0.00012
Chromium VI	parts per million	<0.00050	<0.00050 to 0.00064
Copper	parts per million	0.001716	0.000613 to 0.005230
Iron	parts per million	0.03523	0.01213 to 0.07318
Lead	parts per million	0.000099	<0.000065 to 0.000541
Magnesium	parts per million	5.973	5.450 to 7.285
Manganese	parts per million	0.00907	0.00204 to 0.02812
Mercury	parts per billion	<0.0050	<0.0050 to <0.0050
Nickel	parts per million	0.000206	<0.000021 to 0.000308
Potassium	parts per million	1.244	1.083 to 1.465
Sodium	parts per million	2.245	1.997 to 2.737
Uranium	parts per million	0.000044	<0.000032 to 0.000123
Zinc	parts per million	0.00160	0.00023 to 0.01039

Note: Where value is expressed as less than (<), the value is halved and used in the calculations, where value is expressed as (>), the value is used in the calculations.

Guidelines for Canadian Drinking Water Quality do not apply to Shoal Lake