Surface Water Quality Program

Surface Water Quality

Surface water quality refers to the condition of water found in lakes, rivers, and streams. It is affected by both natural factors and human activities. Monitoring surface water is important for protecting the environment, supporting recreation, and ensuring safe drinking water.

Several key factors influence surface water quality:

1. Nutrient Levels

Excess phosphorus and nitrogen in the water can lead to eutrophication—a process where nutrient overload causes fast algae growth, which can reduce oxygen levels and harm aquatic life. These nutrients come from sources such as agricultural runoff, untreated wastewater, lawn fertilizers, and industrial discharge. Some algal blooms, known as harmful algal blooms (HABs), can pose health risks. A common type is cyanobacteria, which can produce toxins. To learn more about HABs and their potential health impacts, visit the City of Hamilton's Harmful Algal Blooms webpage.

Hamilton Public Health Services monitors water quality at public beaches for levels of cyanobacteria. To learn more visit the Beach Water Quality webpage.

2. Microbial Contaminants

Pathogens like E. coli bacteria can signal the presence of fecal contamination (from human or animal waste), which can pose health risks to people. Sources of E. coli include animal waste, untreated sewage entering stormwater systems, septic systems, and agricultural practices . E. coli (Escherichia coli) is a bacteria that, when consumed, can cause serious illness. In most cases, the illness is self-limiting, with symptoms such as diarrhea, fever, vomiting and abdominal cramps, but it may lead to a life-threatening disease including haemolytic uraemic syndrome (HUS), especially in young children and the elderly. It is transmitted to a person most commonly through consumption of contaminated food or water. 

Hamilton Public Health Services monitors water quality at public beaches for levels of E. coli bacteria. To learn more visit the Beach Water Quality webpage.. 

The City of Hamilton has a large complex wastewater collection network consisting of both separated sewer and combined sewer systems. Modern areas of the City have separated sewer systems, which consist of sanitary sewers that carry wastewater from toilets and household drains in one sewer system, and storm sewers which carry surface water such as rainwater or snowmelt in another separated system. In older areas of the City, a combined sewer system collects both storm water (rainwater or melt water), and wastewater in the same pipe. During periods of heavy rainfall or snowmelt, combined sewers are inundated with large volumes of storm water that can exceed the capacity of the pipes. This can lead to combined sewage, which would include E. coli bacteria, being released to the environment to prevent rainwater and wastewater from backing up and causing basement flooding, surface flooding of our roads and potential damage to the Wastewater Treatment Plants. To learn more about the City’s monitoring of sewer overflow events visit the Monitoring Wastewater Overflows and Bypasses webpage.

To learn how the City is working to reduce sewage entering the stormwater system, visit the Enhanced Sewer Inspection Program webpage.

3. Chemical Pollutants

Chemicals such as pesticides, heavy metals, and industrial pollutants can harm aquatic ecosystems and human health. These substances often enter the water through industrial processes, agricultural practices, and urban runoff.

4. Physical Parameters

Factors such as temperature and pH (the acidity or alkalinity of water) are important indicators of water quality. These factors influence how chemicals behave in the water and affect aquatic life, drinking water, and recreation.

How the City of Hamilton Monitors Surface Water

The City’s Surface Water Quality Program (SWQP) collects and analyzes water samples from rivers, creeks, and streams across Hamilton each month  . These samples are tested for:

• Chemical parameters (e.g., nutrients and metals)
• Biological parameters (e.g., E. coli)
• Physical parameters (e.g., temperature and pH)

The program helps the City understand how infrastructure impacts surface water and supports efforts to reduce pollution. The SWQP also works closely with other City departments and outside partners to share findings and improve water quality.

Surface water sampling locations and data are available on the Open Hamilton Data Portal. This public website provides easy access to water quality information for learning, tracking trends, and research.

Surface Water Sample Locations

The surface water data is exported from the City Laboratory nightly, providing up-to-date surface water quality data through the Open Hamilton Data Portal. Select any sample location on the map to access the data. Once selected, click the ‘Download’ icon near the top left of the Open Hamilton page to access the full dataset through the ‘Download Options’.

Surface Water Quality Parameters

The data collected is reviewed against municipal, provincial and federal regulations and guidelines for general baseline condition purposes only. The guiding documents provide water quality benchmarks, in order to monitor and measure water quality improvements, overtime.  

View a detailed table, outlining the water quality parameters and guiding documents(PDF, 169.18 KB)

Additional water quality data collected within the City of Hamilton and surrounding areas can be accessed, viewed and downloaded from the Great Lakes DataStream. Great Lakes DataStream is an open access platform for sharing information on freshwater health. It brings together water quality datasets collected by monitoring groups throughout the Great Lakes and Saint Lawrence Basin.