2024 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, 2024

What is being measured	How it's measured	No. of samples	Shoal Lake average	Shoal Lake range
Miscellaneous
Carbon,   Dissolved Organic	parts per million	43	9.0	7.6	10.7
Carbon, Total   Organic	parts per million	51	8.3	7.2	9.6
Chlorophyll-a	parts per billion	12	4.7	2.0	7.8
Colour,   Apparent	TCU	12	11.2	5.0	15.0
Colour, True	TCU	12	6.9	5.0	8.5
Conductivity	microsiemens   per centimetre	12	154	143	169
Odour	units	51	85	60	150
pH	units	51	8.04	7.54	8.50
Plankton   (algae) count	cells/mL	12	16,345	2,407	42,460
Solids, Total	parts per million	12	101	91	115
Solids, Total   Dissolved	parts per million	12	84	71	100
Solids, Total   Suspended	parts per million	12	18	<3	29
Temperature	degrees Celcius	17	12.0	2.2	22.9
Turbidity   (clearness)	NTU	64	0.84	0.32	2.15
Anions and   Nutrients
Alkalinity,   Total	parts   per million as calcium carbonate	24	73.9	69.8	80.9
Hardness,   Total	parts   per million as calcium carbonate	12	76.8	71.8	84.7
Chloride	parts per million	4	1.8	1.5	2.0
Fluoride	parts per million	4	0.08	0.07	0.08
Nitrate   Nitrogen	parts per million	10	0.032	0.017	0.059
Perchlorate	parts per billion	4	<0.20	<0.20	<0.20
Phosphorus,   Total Reactive	parts per million	12	0.0048	<0.0010	0.0399
Phosphorus,   Total	parts per million	12	0.0217	0.0108	0.0774
Sulphate	parts per million	4	<0.4	<0.4	0.4
Total Kjeldahl   Nitrogen (TKN)	parts per million	10	0.53	0.47	0.62
Bacteria
Escherichia   Coli	MPN per 100 mL	13	1	<1	5
Total   Coliforms	MPN per 100 mL	13	80	<1	>200
Disinfection   By-Products
Bromodichloromethane	parts per billion	12	<0.4	<0.4	<0.4
Haloacetic   acids	parts per billion	12	<1.2	<1.2	<1.2
Trihalomethanes	parts per billion	12	<2.7	<2.7	<2.7
Enteric   Protozoa
Cryptosporidium	oocysts per 100 L	13	<0.1	<0.1	<0.1
Giardia	cysts per 100 L	13	<0.1	<0.1	<0.1
Metals, Total
Aluminum	parts per million	13	0.00367	0.00090	0.00971
Antimony	parts per million	13	0.000058	<0.000025	0.000082
Arsenic	parts per million	13	0.000759	0.000626	0.001023
Boron	parts per million	13	0.01010	0.00747	0.01203
Cadmium	parts per million	13	<0.000007	<0.000007	<0.000007
Calcium	parts per million	13	19.792	17.858	22.555
Chromium	parts per million	13	<0.00004	<0.00004	0.00008
Chromium VI	parts per million	4	<0.00050	<0.00050	<0.00050
Copper	parts per million	13	0.002123	0.001187	0.003391
Iron	parts per million	13	0.03336	0.00833	0.07678
Lead	parts per million	13	0.000150	<0.000065	0.000250
Magnesium	parts per million	13	6.074	5.423	6.645
Manganese	parts per million	13	0.00788	0.00207	0.02038
Mercury	parts per million	4	<0.0000050	<0.0000050	<0.0000050
Nickel	parts per million	13	0.000166	<0.000021	0.000240
Potassium	parts per million	13	1.189	1.032	1.315
Sodium	parts per million	13	2.371	2.055	2.708
Uranium	parts per million	13	0.000020	<0.000032	0.000039
Zinc	parts per million	13	0.00134	0.00035	0.00281
Phenoxy Acid Herbicides
2,4,5-T	parts per billion	7	<0.50	<0.050	<0.50
2,4,5-TP	parts per billion	7	<0.50	<0.050	<0.50
2,4-D	parts per billion	7	<0.50	<0.050	<0.50
2,4-DB	parts per billion	7	<0.50	<0.050	<0.50
2,4-DP	parts per billion	7	<0.50	<0.050	<0.50
Asulam	parts per billion	7	<0.10	<0.010	<0.10
Brodifacoum	parts per billion	7	<0.10	<0.010	<0.10
Bromacil	parts per billion	7	<1.0	<0.10	<1.0
Bromoxynil	parts per billion	7	<0.50	<0.050	<0.50
Clopyralid	parts per billion	7	<1.0	<0.20	<1.0
Dicamba	parts per billion	7	<1.0	<0.10	<1.0
Diflufenican	parts per billion	7	<0.10	<0.010	<0.10
Dinoseb	parts per billion	7	<0.50	<0.050	<0.50
Linuron	parts per billion	7	<1.0	<0.10	<1.0
MCPA	parts per billion	7	<0.50	<0.050	<0.50
MCPB	parts per billion	7	<0.50	<0.10	<0.50
Mecoprop	parts per billion	7	<0.50	<0.050	<0.50
Nicarbazin	parts per billion	7	<0.10	<0.010	<0.10
Oryzalin	parts per billion	7	<0.50	<0.050	<0.50
Picloram	parts per billion	7	<1.0	<0.20	<1.0
Terbacil	parts per billion	7	<0.10	<0.010	<0.10
Polychlorinated Biphenyls
Arochlor 1016	parts per billion	7	<0.20	<0.020	<0.20
Arochlor 1221	parts per billion	7	<0.20	<0.020	<0.20
Arochlor 1232	parts per billion	7	<0.20	<0.020	<0.20
Arochlor 1242	parts per billion	7	<0.20	<0.020	<0.20
Arochlor 1248	parts per billion	7	<0.20	<0.020	<0.20
Arochlor 1254	parts per billion	7	<0.20	<0.020	<0.20
Arochlor 1260	parts per billion	7	<0.20	<0.020	<0.20
Arochlor 1262	parts per billion	7	<0.20	<0.020	<0.20
Arochlor 1268	parts per billion	7	<0.20	<0.020	<0.20
Pesticides
Alachlor	parts per billion	6	<0.050	<0.050	<0.050
Aldicarb	parts per billion	6	<0.10	<0.10	<0.10
Aldrin	parts per billion	7	<0.0080	<0.0080	<0.0080
alpha-Chlordane	parts per billion	7	<0.0080	<0.0080	<0.0080
alpha-Endosulfan	parts per billion	7	<0.0070	<0.0070	<0.0070
alpha-HCH	parts per billion	7	<0.0080	<0.0080	<0.0080
Atrazine	parts per billion	6	<0.050	<0.050	<0.050
Azinphos-methyl	parts per billion	6	<0.10	<0.10	<0.10
Bendiocarb	parts per billion	6	<0.0250	<0.0250	<0.0250
beta-Endosulfan	parts per billion	7	<0.0070	<0.0070	<0.0070
beta-HCH	parts per billion	7	<0.0080	<0.0080	<0.0080
Carbaryl	parts per billion	6	<0.050	<0.050	<0.050
Carbofuran	parts per billion	6	<0.0250	<0.0250	<0.0250
Chlordane	parts per billion	7	<0.0110	<0.0110	<0.0110
Chlorothalonil	parts per billion	6	<0.050	<0.050	<0.050
Chlorpyrifos	parts per billion	6	<0.10	<0.10	<0.10
Cyanazine	parts per billion	6	<0.10	<0.10	<0.10
delta-HCH	parts per billion	7	<0.0080	<0.0080	<0.0080
Diazinon	parts per billion	6	<0.0250	<0.0250	<0.0250
Diclofop-methyl	parts per billion	6	<0.10	<0.10	<0.10
Dieldrin	parts per billion	7	<0.0080	<0.0080	<0.0080
Dimethoate	parts per billion	6	<0.050	<0.050	<0.050
Diuron	parts per billion	6	<0.050	<0.050	<0.050
Endosulfan	parts per billion	7	<0.010	<0.010	<0.010
Endosulfan   Sulfate	parts per billion	7	<0.0070	<0.0070	<0.0070
Endrin	parts per billion	7	<0.010	<0.010	<0.010
Endrin   Aldehyde	parts per billion	7	<0.010	<0.010	<0.010
Ethalfluralin	parts per billion	6	<0.10	<0.10	<0.10
EPTC (Eptam)	parts per billion	6	<0.50	<0.50	<0.50
gamma-Chlordane	parts per billion	7	<0.0080	<0.0080	<0.0080
gamma-HCH   (Lindane)	parts per billion	7	<0.0080	<0.0080	<0.0080
Heptachlor	parts per billion	7	<0.0080	<0.0080	<0.0080
Heptachlor   Epoxide	parts per billion	7	<0.0080	<0.0080	<0.0080
Hexachlorobenzene	parts per billion	7	<0.0080	<0.0080	<0.0080
Hexachlorobutadiene	parts per billion	7	<0.0080	<0.0080	<0.0080
Hexachlorocyclohexane,   total	parts per billion	7	<0.0160	<0.0160	<0.0160
Hexachloroethane	parts per billion	7	<0.0080	<0.0080	<0.0080
Malathion	parts per billion	6	<0.0250	<0.0250	<0.0250
Methoxychlor	parts per billion	7	<0.0080	<0.0080	<0.0080
Methyl   Parathion	parts per billion	6	<0.10	<0.10	<0.10
Metolachlor	parts per billion	6	<0.0250	<0.0250	<0.0250
Metribuzin	parts per billion	6	<0.10	<0.10	<0.10
Metsulfuron-methyl	parts per billion	6	<0.050	<0.050	<0.050
Mirex	parts per billion	7	<0.0080	<0.0080	<0.0080
Omethoate	parts per billion	6	<0.050	<0.050	<0.050
Oxychlordane	parts per billion	7	<0.0080	<0.0080	<0.0080
o,p-DDD	parts per billion	7	<0.0040	<0.0040	<0.0040
o,p-DDE	parts per billion	7	<0.0040	<0.0040	<0.0040
o,p-DDT	parts per billion	7	<0.0040	<0.0040	<0.0040
p,p-DDD	parts per billion	7	<0.0040	<0.0040	<0.0040
p,p-DDE	parts per billion	7	<0.0040	<0.0040	<0.0040
p,p-DDT	parts per billion	7	<0.0040	<0.0040	<0.0040
Total-DDD	parts per billion	7	<0.0060	<0.0060	<0.0060
Total-DDE	parts per billion	7	<0.0060	<0.0060	<0.0060
Total-DDT	parts per billion	7	<0.0060	<0.0060	<0.0060
Parathion	parts per billion	6	<0.10	<0.10	<0.10
Pentachloronitrobenzene	parts per billion	7	<0.010	<0.010	0.025
Phorate	parts per billion	6	<0.250	<0.250	<0.250
Propachlor	parts per billion	6	<0.0250	<0.0250	<0.0250
Propanil	parts per billion	7	<0.10	<0.010	<0.10
Propoxur	parts per billion	6	<0.0250	<0.0250	<0.0250
Simazine	parts per billion	6	<0.10	<0.10	<0.10
Terbufos	parts per billion	6	<0.50	<0.50	<0.50
Trans-Nonachlor	parts per billion	7	<0.010	<0.010	<0.010
Triallate	parts per billion	6	<0.10	<0.10	<0.10
Trichlopyr	parts per billion	7	<0.50	<0.050	<0.50
Trifluralin	parts per billion	6	<0.10	<0.10	<0.10

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