Grimsby Water Treatment Plant - 2025 Annual Water Quality Report
This annual water quality report summarizes the quality of drinking water from the Grimsby Water Treatment Plant, drinking water system number 220007150, from Jan. 1 to Dec. 31, 2025.
This report satisfies the requirements of Ontario Regulation 170/03 - Drinking Water Systems.
Description of drinking water system
A conventional surface water treatment plant incorporates the following steps in its purification process:
- Zebra mussel control
- Travelling screens
- Coagulation
- Flocculation
- Sedimentation
- Filtration
- Disinfection
The plant has a rated daily flow capacity of 44,000 m3/day. Primary disinfection is achieved with sodium hypochlorite.
The Grimsby Water Treatment Plant supplies water to the towns of Grimsby (260001851), Lincoln (260004319) and West Lincoln (260002876) in Niagara. The Grimsby Water Treatment Plant is located on Lot 115, Concession 1, in North Grimsby.
The water treatment chemicals used over this reporting period are:
- Sodium hypochlorite
- Aluminum sulphate
Water treatment plant infrastructure / system infrastructure
Monetary expenses
To ensure safe and efficient operations, the following major repairs or upgrade projects took place:
- Ontario Street watermain replacement - $1,586,657
- New transmission main Smithville - $726,415
- Plant expansion - $219,697
- New trunk watermain from the plant to Parkridge Reservoir - $157,997
- Phase 2 Grimsby watermain replacement (Baker Road to Park Road) - $140,595
- Low lift pump addition - $108,895
- Grimsby water system storage addition (15 ML) - $39,093.75
Summary of adverse water quality incidents
The following table summarizes the notices of adverse water quality incidents submitted in accordance with the Safe Drinking Water Act. Adverse water quality incidents are reported to the Spills Action Centre and the Medical Officer of Health.
| Incident date | Location | Adverse condition | Corrective action | Notice of issue resolution |
|---|---|---|---|---|
| Sept. 9 | Smithville Elevated Tank | Laboratory sample likely contaminated. Sample ID: 5716-5T taken Sept. 8 at 10:54 a.m. Analytical results: 2 total coliform, 1 E. coli FAC = 0.92 mg/L |
Sample ports thoroughly flushed. Two sets of samples were collected and submitted to an external lab for analysis: the location of the original sample in question and upstream and downstream locations. Both resampled bacteriological analytical results were negative. |
Sept. 12 |
| Nov. 6 | Grimsby Water Treatment Plant | Drawdown sight tube was left closed after drawdown tests were done which caused possible underdosing of alum on Side B of the treatment train. The relief in the plant Municipal Drinking Water Licence states that a loss of coagulation greater than 20 minutes must be reported. Even though there was no alarm for loss of coagulation and the flow meter showed flow, proper dosage cannot be confirmed for that time frame. |
Alum flow was restored to Side B of the treatment train. The alum pump was run at max speed for a few minutes to clear any air in the line. Drawdown confirmed proper alum dosage is being attained. Instrumentation was called in and confirmed that the alum flow meter was reading correctly. Operators did manual turbidity samples every half hour on Side B settled water and every hour on Filters 3 and 4 effluent turbidities to monitor effects of possible underdosing. No abnormal turbidity readings were noted and all samples were well within operating parameters. |
Nov. 6 |
Water quality test results
Reported results that are shown with "ND" (non-detect) instead of a numerical value indicates that the sample result is below the lowest possible detection limit for the parameter.
Microbiological testing
Microbiological testing carried out under Schedule 10 of Ontario Regulation 170/03 - Drinking Water systems, during this reporting period.
| Location | Number of samples | Range of E.coli results (minimum number) - (maximum number) | Range of total coliform results (minimum number) - (maximum number) | Prescribed standard* | Unit of measure |
|---|---|---|---|---|---|
| Raw | 52 | 0 - 2 | 0 - 140 | Not applicable | CFU/100 ml |
| Treated | 52 | 0 | 0 | Not detectable | CFU/100 ml |
| Distribution | 210 | 0 | 0 | Not detectable | CFU/100 ml |
*Prescribed standards are copied from Ontario Regulation 169/03 - Ontario Drinking Water Quality Standards.
Heterotrophic plate count testing
Heterotrophic plate count testing (HPC) is conducted on some treated and distribution system samples. The heterotrophic plate count test is used as a tool to monitor overall quality, but the results are not indicators of water safety. There is no prescribed standard for heterotrophic plate count.
| Location | Number of samples | Range of HPC results (minimum number) - (maximum number) | Unit of measure |
|---|---|---|---|
| Treated | 52 | 0 - 2 | CFU/ml |
| Distribution | 210 | 0 - 8 | CFU/ml |
Operational testing
Operational testing carried out under Schedule 7 of Ontario Regulation 170/03 - Drinking Water Systems, during this reporting period. An analyzer continuously monitors the water treatment process and records results on a predetermined frequency. Where continuous monitors are used, 8,760 is reflected as the number of samples.
| Parameter | Number of samples | Range of results (minimum number) - (maximum number) | Unit of measure |
|---|---|---|---|
| Filter turbidity | 8,760 | 0.012 - 0.231 | NTU* |
| Treated chlorine | 8,760 | 0.92 - 1.27 | mg/L |
*NTU (nephelometric turbidity units) is a unit that measures the lack of water clarity.
Additional testing
Summary of additional testing and sampling carried out in accordance with the requirement of an approval, order or other legal instrument.
| Date of legal instrument issued | Location: parameter | Date sampled | Result value or range (minimum number) - (maximum number) | Requirement | Unit of measure |
|---|---|---|---|---|---|
Municipal Drinking Water Licence |
Environmental discharge: free chlorine residual | Weekly (January to December) | 0 - 0.01 | < 0.02 | mg/L |
Municipal Drinking Water Licence |
Environmental discharge: total suspended solids | Monthly (January to December) |
< 3 - 92 | 25 (running annual average) | mg/L |
| Municipal Drinking Water Licence Issue 10 Dec. 16, 2024 |
Raw: microcystin | Weekly (June to October) | ND | 0.0015* | mg/L |
| Municipal Drinking Water Licence Issue 10 Dec. 16, 2024 |
Treated: microcystin | Weekly (June to October) | ND | 0.0015* | mg/L |
*Prescribed standards are copied from Ontario Regulation 169/03 - Ontario Drinking Water Quality Standards.
Inorganic testing
Inorganic parameter testing carried out under Schedule 13 of Ontario Regulation 170/03 - Drinking Water Systems, during this reporting period. Inorganic substances include heavy metals and dissolved minerals that may be present in treated drinking water.
| Parameter | Number of samples | Last sample date | Range of results (minimum number) - (maximum number) | Prescribed standard* | Unit of measure | Exceedance |
|---|---|---|---|---|---|---|
| Antimony | 4 | Nov. 5 | ND |
0.006 | mg/L | No |
| Arsenic | 4 | Nov. 5 | ND - 0.0006 | 0.01 | mg/L | No |
| Barium | 4 | Nov. 5 | 0.021 - 0.023 | 1 | mg/L | No |
| Boron | 4 | Nov. 5 | 0.021 - 0.026 | 5 | mg/L | No |
| Cadmium | 4 | Nov. 5 | ND | 0.005 | mg/L | No |
| Chromium | 4 | Nov. 5 | ND - 0.001 | 0.05 | mg/L | No |
| Fluoride | 12 | Nov. 5 | ND - 0.08 | 1.5 | mg/L | No |
| Mercury | 4 | Nov. 5 | ND | 0.001 | mg/L | No |
| Nitrate | 12 | Nov. 5 | 0.2 - 0.42 | 1 | mg/L | No |
| Nitrite | 12 | Nov. 5 | ND | 10 | mg/L | No |
| Selenium | 4 | Nov. 5 | < 0.0004 - 0.0005 | 0.05 | mg/L | No |
| Sodium | 4 | Nov. 5 | 15.5 - 16.9 | 20 | mg/L | No |
| Uranium | 4 | Nov. 5 | ND | 0.02 | mg/L | No |
*Prescribed standards are copied from Ontario Regulation 169/03 - Ontario Drinking Water Quality Standards. The prescribed standard for sodium is copied from Ontario Regulation 170/03 - Drinking Water Systems.
Lead testing
Lead testing carried out under Schedule 15.1 of Ontario Regulation 170/03 - Drinking Water Systems, during this reporting period.
| Location type | Number of samples | Last sample date | Range of lead results (minimum number) - (maximum number) | Prescribed standard* | Unit of measure | Exceedance |
|---|---|---|---|---|---|---|
| Treated | 4 | Nov. 5 | ND | 0.010 | mg/L | No |
| Distribution | 4 | Nov. 5 | ND | 0.010 | mg/L | No |
*Prescribed standards are copied from Ontario Regulation 169/03 - Ontario Drinking Water Quality Standards.
Organics testing
Organic parameter testing carried out under Schedule 13 of Ontario Regulation 170/03 - Drinking Water Systems, during this reporting period. Trace organic test parameters include: volatile organic substances, pesticides, solvents, dioxins, PCBs and disinfection by-products.
| Parameter | Number of samples | Last sample date | Range of results (minimum number) - (maximum number) | Prescribed standard* | Unit of measure | Exceedance |
|---|---|---|---|---|---|---|
| 1,1-Dichloroethylene (vinylidene chloride) | 4 | Nov. 5 | ND | 0.014 | mg/L | No |
| 1,2-Dichlorobenzene | 4 | Nov. 5 | ND | 0.2 | mg/L | No |
| 1,2-Dichloroethane | 4 | Nov. 5 | ND | 0.005 | mg/L | No |
| 1,4-Dichlorobenzene | 4 | Nov. 5 | ND | 0.005 | mg/L | No |
| 2,3,4,6-Tetrachlorophenol | 4 | Nov. 5 | ND | 0.1 | mg/L | No |
| 2,4,6-Trichlorophenol | 4 | Nov. 5 | ND | 0.005 | mg/L | No |
| 2,4-Dichlorophenoxy acetic acid (2,4-D) | 4 | Nov. 5 | ND | 0.1 | mg/L | No |
| 2-4 Dichlorophenol | 4 | Nov. 5 | ND | 0.9 | mg/L | No |
| 2-Methyl-4-chlorophenoxyacetic acid (MCPA) | 4 | Nov. 5 | ND | 0.1 | mg/L | No |
| Alachlor | 4 | Nov. 5 | ND | 0.005 | mg/L | No |
| Atrazine + N-dealkylated metabolites | 4 | Nov. 5 | ND | 0.005 | mg/L | No |
| Azinphos-methyl | 4 | Nov. 5 | ND | 0.02 | mg/L | No |
| Benzene | 4 | Nov. 5 | ND | 0.001 | mg/L | No |
| Benzo(a)pyrene | 4 | Nov. 5 | ND | 0.00001 | mg/L | No |
| Bromoxynil | 4 | Nov. 5 | ND | 0.005 | mg/L | No |
| Carbaryl | 4 | Nov. 5 | ND | 0.09 | mg/L | No |
| Carbofuran | 4 | Nov. 5 | ND | 0.09 | mg/L | No |
| Carbon tetrachloride | 4 | Nov. 5 | ND | 0.002 | mg/L | No |
| Chlorpyrifos | 4 | Nov. 5 | ND | 0.09 | mg/L | No |
| Diazinon | 4 | Nov. 5 | ND | 0.02 | mg/L | No |
| Dicamba | 4 | Nov. 5 | ND | 0.12 | mg/L | No |
| Dichloromethane | 4 | Nov. 5 | ND | 0.05 | mg/L | No |
| Diclofop-methyl | 4 | Nov. 5 | ND | 0.009 | mg/L | No |
| Dimethoate | 4 | Nov. 5 | ND | 0.02 | mg/L | No |
| Diquat | 4 | Nov. 5 | ND | 0.07 | mg/L | No |
| Diuron | 4 | Nov. 5 | ND | 0.15 | mg/L | No |
| Glyphosate | 4 | Nov. 5 | ND | 0.28 | mg/L | No |
| HAA - Distribution (latest running annual average) | 12 | Dec. 17 | 0.020 | 0.080 (running annual average) | mg/L | No |
| Malathion | 4 | Nov. 5 | ND | 0.19 | mg/L | No |
| Metolachlor | 4 | Nov. 5 | ND | 0.05 | mg/L | No |
| Metribuzin | 4 | Nov. 5 | ND | 0.08 | mg/L | No |
| Monochlorobenzene | 4 | Nov. 5 | ND | 0.08 | mg/L | No |
| Paraquat | 4 | Nov. 5 | ND | 0.01 | mg/L | No |
| Pentachlorophenol | 4 | Nov. 5 | ND | 0.06 | mg/L | No |
| Phorate | 4 | Nov. 5 | ND | 0.002 | mg/L | No |
| Picloram | 4 | Nov. 5 | ND | 0.19 | mg/L | No |
| Polychlorinated Biphenyls (PCB) | 4 | Nov. 5 | ND | 0.003 | mg/L | No |
| Prometryne | 4 | Nov. 5 | ND | 0.001 | mg/L | No |
| Simazine | 4 | Nov. 5 | ND | 0.01 | mg/L | No |
| Terbufos | 4 | Nov. 5 | ND | 0.001 | mg/L | No |
| Tetrachloroethylene | 4 | Nov. 5 | ND | 0.01 | mg/L | No |
| THM - Distribution (latest running annual average) | 12 | Dec. 17 | 0.029 | 0.100 (running annual average) |
mg/L | No |
| Triallate | 4 | Nov. 5 | ND | 0.23 | mg/L | No |
| Trichloroethylene | 4 | Nov. 5 | ND | 0.005 | mg/L | No |
| Trifluralin | 4 | Nov. 5 | ND | 0.045 | mg/L | No |
| Vinyl Chloride | 4 | Nov. 5 | ND | 0.001 | mg/L | No |
*Prescribed standards are copied from Ontario Regulation 169/03 - Ontario Drinking Water Quality Standards.
Parameters exceeding prescribed half-standard
Any inorganic or organic parameter(s) that exceeded half the standard prescribed in Schedule 2 of prescribed standards documented in Ontario Regulation 169/03 - Ontario Drinking Water Quality Standards or prescribed standards documented within Ontario Regulation 170/03 - Drinking Water Systems for large municipal residential drinking water systems.
Sodium - prescribed standard is <=20*
| Result value or range (minimum number) - (maximum number) | Date of sample |
|---|---|
| 15.5 - 16.9 mg/L | Feb. 3 |
*Prescribed standards are copied from Ontario Regulation 169/03 - Ontario Drinking Water Quality Standards. The prescribed standard for sodium is copied from Ontario Regulation 170/03 - Drinking Water Systems.
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