Water quality testing is an important part of environmental monitoring. When water quality is poor, it affects not only aquatic life and the surrounding ecosystem, but also public health. In Canada, Health Canada in collaboration with the Federal-Provincial-Territorial Committee on Drinking Water develops guidelines for drinking water quality in public water systems. Responsibilities for monitoring and ensuring water quality are spread among many Federal, Provincial, Territorial, and local government agencies. 

Monitoring water quality is a growing challenge due to the large number of chemicals and other contaminants used in our everyday lives and in industry that can make their way into our water supply. Monitoring water quality is important for both environmental protection and public health.

Numerous factors and contaminants can affect the quality of water, and these typically fall under three domains: physical, chemical and biological.

• Physical: Temperature and turbidity can impact water quality.
• Chemical: pH levels, dissolved oxygen and high levels of naturally occurring chemicals (such as arsenic, radon, uranium) can impact water quality.
• Biological: Algae, phytoplankton, sewage, on-site water treatment systems (like septic systems) or livestock runoffs can impact water quality. 

These factors are relevant to monitoring and assessing the quality of surface water (like oceans, lakes and rivers), but can also affect the quality of groundwater and have wide reach repercussions for industries and residential drinking water.

Consistent and accurate water quality monitoring provides the necessary evidence to make decisions on managing water quality. Routine water quality monitoring and collecting water data can alert you to current, ongoing and future problems, helping you to make timely decisions. 

Measuring and Monitoring Water Quality

A range of different techniques and tools are used to measure and monitor water quality. Measuring water quality allows specialists to understand potential causes of contamination. On top of hydrological measurements used in measuring the environmental water quality of larger bodies of water, there is a range of water quality measurements that can be used at smaller scales for residential or commercial uses. 

There are four key parameters for water analysis for residential, commercial and industrial purposes.

pH

Whether you're attempting to determine the quality of water for residential, commercial, or industrial purposes, one of the most effective measurements to take is the pH of the water which will indicate if the water is acidic or alkaline. Water is considered to be neutral at a pH of 7. If the pH of water is too high or too low, aquatic organisms living within it will die. pH can also impact the solubility and toxicity of chemicals and heavy metals in the water. Humans tend to have a higher tolerance for pH variability (humans can consume water with pH levels between 4-11). Higher and lower pH ranges can cause negative health issues in humans and pH levels outside of 6.5-9.5 can cause damage to pipes and other systems, increasing heavy metal toxicity

Measuring the pH level of water is straightforward and there are several sensors and meters to measure the pH level of your water source either on-site or remotely. 

Oxidation-Reduction Potential

The oxidation-reduction potential, or ORP, of water measures the ability of a body of water to cleanse itself or break down waste, such as contaminants or dead biological matter. When the ORP value is high, there is a lot of oxygen present in the water, allowing bacteria to decompose contaminants more effectively. Higher ORP levels can be correlated with higher levels of sanitation, which is important for monitoring drinking water quality or determining if the ORP of water is high enough for use in swimming pools. 

There are tools available to measure and monitor ORP in a water source. 

Conductivity

Conductivity is a measure of water's ability to pass electrical current and is directly related to the concentration of ions present in the water. Conductive ions can come from salts and inorganic materials. The more conductive ions present, the higher the conductivity of the water. Each body of water tends to have a relatively consistent range of conductivity that can be used as a baseline for comparison with regular conductivity measurements.

If there are significant changes in conductivity, it could be an indicator that there is discharge or another source of pollution in the water source. These changes in conductivity can negatively impact the condition or health of the water and the organisms that live in it, which can, in turn, negatively impact the surrounding environment or human health.

Consistent monitoring of conductivity is important to prevent the loss of aquatic life and maintain safe drinking water. There are tools available to measure and monitor the levels of conductivity in a water source.

Temperature

Temperature is an important factor in assessing water quality. In addition to its own effects, temperature can influence several other water quality parameters and can alter the physical and chemical properties of water. On its own, changes in water temperature can affect the metabolic rates and biological activity of aquatic organisms, which can affect the solubility and toxicity of certain compounds in the water. Changes in water temperature can impact the parameters listed above as well as compound toxicity and water density. 

Measuring water temperature is an important element of monitoring water quality. There are numerous tools available to measure and monitor water temperature. 

Dissolved Oxygen

Dissolved oxygen refers to the level of non-compound oxygen (or oxygen that is freely found in water and not bound to hydrogen). Dissolved oxygen often enters the water through the air or as a plant byproduct. Unusual levels of dissolved oxygen can harm aquatic life and affect water quality by allowing contaminants to exist at unsafe levels (like an algae bloom) making the water undrinkable. 

Proper monitoring of dissolved oxygen is important to prevent the loss of aquatic life. There are tools available to measure and monitor the levels of dissolved oxygen in a water source.