Water System Monitoring


Record keeping is one of the most important parts of a water operator’s responsibilities. It helps you quickly recognize when there is a problem anywhere in your system and correct it before there are any threats to human health.

Regular monitoring of your small water system ensures that drinking water is safe and reliable by

  • Helping identify problems early so you can take action quickly and efficiently
  • Ensuring your treatment system is working properly
  • Providing information about your water source, including changes in water quality

By being familiar with your system’s normal operating parameters, you can readily identify changes and be prepared to take action.

Glossary of Terms

Related to the study of bacteria.


The introduction into water of micro-organisms, chemicals, toxic substances, wastes, or wastewater in a concentration that makes the water unfit for its  intended use.


The process designed to kill or inactivate most microorganisms in water, including essentially all pathogenic (disease-causing) bacteria. There are several ways to disinfect, with chlorination being the most frequently used in water treatment.

distribution system

The equipment involved with the delivery of treated water from the treatment facility to the intended end-point user.

indicator bacteria

Bacteria in a water sample which indicates that fecal contamination is present.

pressure tank

A tank used in water systems to maintain pressure and provide storage.


A pond, lake, basin, or other structure (natural or artificial) that stores, regulates, or controls water.


The cloudy appearance of water caused by the presence of suspended and colloidal matter. In the waterworks field, a turbidity measurement is used to indicate the clarity of water. Technically, turbidity is an optical property of the water based on the amount of light reflected by suspended particles.


Large distribution pipes that run along road major roadways.

well log

Records kept during well drilling that record the type of soil encountered, at what depths, and some characteristics of the aquifer.

You will monitor all the components of the system by 

  • regularly checking infrastructure
  • observing and recording data provided by treatment and monitoring equipment 
  • sampling and testing water at various points along the system for different parameters

Best Practices in water system monitoring include having a water system monitoring plan and keeping records of monitoring activities.


The purpose of sampling is to collect a representative amount of water to be tested for various characteristics, or parameters, that will provide information on the safety and operation of your water system.

Many parameters are time sensitive and need to be tested within a certain amount of time after sampling, often called the hold-time.

Sampling is a snapshot in time. The conditions shown in today’s sample can change tomorrow, so sampling must be done regularly.

Your local health authority can provide you with information on proper sampling techniques and approved laboratories. For an example of sampling techniques, read How to Submit a Water Sample (Interior Health).

Depending on the parameters being sampled, a specific type of bottle or container will be required and sometimes a special preservative is added to the container before sampling. An analytical testing laboratory can supply the correct containers with any required preservatives and advise on hold-times. 

Monitoring bottle being filled from tap
Figure 1: Taking a sample from a tap. Source: Interior Health.


Microbiological, Chemical and Physical Parameters to Monitor

You will be sampling for certain microbiological, chemical and physical characteristics:

  1. Microbiological Parameters, such as bacteria, viruses and parasites. These are usually monitored by sampling and testing for indicator bacteria.
  2. Chemical and Physical Parameters, such as metals, including arsenic and uranium; anions, including nitrates and fluorides; chlorine; and turbidity. These are usually monitored by sampling and testing directly for the parameter of interest.

Exactly which parameters need to be monitored and how often will depend on the nature of your water system. For example, a system with a water source close to agricultural activity may need to monitor the source water for nitrates several times a year.

B.C.'S Drinking Water Protection Act requires you to take regular bacteriological samples. Your drinking water officer will have indicated on your operating permit how often you need to take samples and from where. These samples will be tested for coliforms (e.g., fecal coliforms and E. coli), which indicate if fecal matter could be present.

Starting with a baseline chemical and physical analysis of your water source, you and your Drinking Water Officer will identify a list of substances that should to be routinely evaluated and from there establish a monitoring program that suits your situation.

The Guidelines for Canadian Drinking Water Quality set the maximum acceptable concentrations for chemical parameters, which will help you set up appropriate treatment procedures for your situation. An example of a Chemical Analysis Form, from the Northern Health Authority, is attached here.

Water System Monitoring Plan

A water system monitoring plan will be different for every water system. It will depend on the water source, any specific parameters of concern, type of water treatment and other infrastructure. The plan should identify what parameters need to be monitored, how often they should be monitored, and any special instructions that need to be followed to collect the sample.

Record Keeping

It is important to keep detailed records to keep track of water system performance over time. The records can also be used to demonstrate that the water being provided is safe.

Regularly Check Infrastructure

From source-to-tap, you should check your system for vulnerabilities on a regular basis.

Infrastructure: At a minimum, you should include the following items from your infrastructure in your monitoring plan

  • New Construction Records: wells, pumps, boosters, storage tanks, water mains, disinfection equipment – recorded on an as-built drawing
    • For Wells: well drillers’ report, well log, pump suppliers’ equipment sheet, construction details of pump base, motor specifications, pump controls wiring diagrams, parts lists, etc.
    • Operating Instructions for all of the above
  • Equipment Records: manufacturers’ specifications and instructions, warranty documentation
  • Repairs and Modifications: include a drawing of the work done

Monthly Operational Record: You should have a monthly operational record at each facility in your system. Each time you visit the facility, fill it out indicating

  • the purpose of the visit (e.g., routine service),
  • equipment measurements (e.g., meter readings, air level in pressure tank, water level in well before and after pumping, etc.) and
  • actions taken (e.g., lube oil added).

Sample log sheets are available at Appendix C in Small Water System Guidebook (BC Ministry of Health). 

Representative Sampling

Representative Sampling means sampling a portion of water that is as nearly identical in content and consistency as possible to the larger body of water being sampled.

Most bodies of water are not well mixed—the characteristics are not the same from spot to spot—challenging attempts to get a representative sample. So, we take small portions of water from points across the water body or tank and mix them together into what is called a composite sample.

Proper sampling procedures are essential to obtain accurate information on the condition of your water.

Source Water Sampling:

  • Rivers: The sample(s) must represent the entire flow at that time
  • Streams: For small- or medium-sized streams, a single sampling point may be possible. Larger streams may require more than one sample.
  • Reservoirs and Lakes: In reservoirs and lakes, the water is usually poorly mixed, so a number of samples need to be collected from different depths and areas.
  • Groundwater:­ Groundwater also does not usually mix. Usually the only way to take a sample is from a pumped sample. If the pump has not run for some time, well pumps and casing may contribute to sample contamination, as can leaking seals and oils.

In-Plant Sampling:

Here, too, the samples need to be representative of the water passing through a particular point of the plant, not in dead zones of the reservoir. Have the sample taps at points that are representative of the passing water. Follow the protocols for sampling from a tap.

Distribution System Sampling:

Sampling from the distribution system gives a true indication of the quality of water being delivered to the customer. For smaller water systems, use the customer’s faucet to collect the sample. The best sample points are front yard faucets on homes supplied by short service lines, because the short service lines are located on the same side of the street as the water main. An ideal sample station has a short, direct connection with the main and is made of corrosion-resistant material.

Sampling Videos