Monitoring Water Quality

Checking the quality of a drinking water system is a critical part of providing safe water and an important part of owning and operating a small water system.

Monitoring and comparing water chemistry with the accepted standards for health and aesthetic quality ensures the correct treatment options are selected when necessary. Scheduled, routine checks can help in identifying potential sources of contamination.

Many things can affect the quality of the water you distribute:

• Water quality at the source may vary at any time. This is especially true of surface water sources.
• Water quality tends to deteriorate as the water moves through the system; pH, temperature, taste, odour, colour, and bacteria may be affected.
• Contaminants can enter the system through leaks, breaks, and cross-connections.
  

Therefore, it’s important to obtain water samples regularly and from various locations throughout the distribution system.  For help in identifying changes in water quality, develop a Water Quality Monitoring Program for your water distribution system.

Water Quality Monitoring Program

This is a written document that outlines how you ensure your water is safe to drink. In this document, you should write down the details of how you monitor your water system; the who, what, when, where, why, and how. For instance:

• Is monitoring done manually or automatically?
• Are there any customer complaints that might indicate quality problems*?

* If you find quality problems in the system, immediately activate your Emergency Response Plan.

Part of your Emergency Response Plan involves reporting any problems. Reporting is communicating operating information to those who need to know such as water users and health authorities.

A report might include details about chemical, biological, and usage problems. Maintaining an up-to-date Monitoring Program document means you will be prepared to report valuable information in an emergency.

Monitoring Schedule

An important part of your monitoring program is the monitoring schedule. This outlines the frequency with which the different parts of the water system need to be checked.

The frequency of monitoring depends on:

• the importance of a component to the operation of the system
• the likelihood the component will change or fail

You should customize the monitoring routine for your water system, taking into account its complexity and size. This routine can include automated monitoring equipment and daily, weekly, and periodic manual monitoring.

Continuous Monitoring
Some water systems need equipment capable of performing continuous monitoring because of concerns about:

• UV light intensity
• high chlorine levels
• incoming turbidity levels

Failure of continuous monitoring systems to perform up to standard, and/or a significant deterioration of water quality can become a threat to water users. You must take immediate action to correct these problems.

Daily or More Frequent Monitoring
Where continuous monitoring equipment, such as a continuous chlorine analyzer, is not available (e.g.,), manual methods of testing are required. These tests are necessary for those activities that are more likely to cause a threat to water users should quality levels not be maintained.

Weekly or More Frequent Monitoring
A number of monitoring tasks are less urgent than others. You need to do these on a routine, but not daily, basis. For example, you need to check the amount of chlorine that remains in the chemical feed tank.

Less Frequent Monitoring
Some monitoring tasks only need to be done every now and then, but are still a necessary part of the operation of the water system. For example, you should periodically check your reservoir security.