Top 4 FAQs Answered About Water Quality After a Fire

Posted on September 15, 2023

Water QualityAfter a rough wildfire season in BC and Alberta, it’s normal to come out of the thick of it and wonder – what’s next? CARO is here to help with what we do best: quick and reliable water testing.   Forest fires can have a significant impact on drinking water quality, and to help you figure out your next steps, we’ve put together a list of the most common FAQs our team of scientists’ field after a major fire event.
(VIP BONUS: keep an eye out for a special offer at the end of this post.)

1. How do forest fires affect drinking water quality?

A forest fire can lead to changes in the environment that impact water quality in several ways:

  • Run off

During a forest fire, the intense heat can burn vegetation and organic material on the forest floor. This leaves behind a layer of ash and charred debris. When heavy rains occur after the fire, this ash and debris can be washed into nearby rivers, streams, and reservoirs, leading to increased sediment and turbidity in the water. This can make water treatment more challenging and affect the clarity of drinking water.

  • Direct entry from rain water/fire fighting implements

Forest fires can release various pollutants and contaminants into the environment. These can include substances like heavy metals, organic compounds, and even radioactive materials from burned vegetation, soil, and human-made structures. These pollutants can find their way into water bodies and pose a risk to water quality and human health if not properly treated.

  • Damaged distribution systems

Forest fires can affect the landscape by killing microorganisms that typically help filter and purify water in natural systems. This loss of microbial diversity can result in increased microbial contamination in water sources, potentially leading to waterborne diseases if not properly treated. Forest fires can damage infrastructure like water treatment facilities, pipelines, and reservoirs. This damage can lead to increased vulnerability in the water distribution system and potential contamination of drinking water.

  • Changes in water chemistry due to more nutrients, or less microbes

The combustion of organic matter during forest fires releases chemicals into the atmosphere. When these chemicals come into contact with water droplets in the air, they can form acids that can subsequently be deposited into water bodies as acid rain. This altered water chemistry can impact the pH and overall chemical composition of water sources, affecting aquatic ecosystems and potentially requiring adjustments to water treatment processes.

Additionally, the release of nutrients like nitrogen and phosphorus from burned vegetation can lead to an increase in nutrient load in water bodies. While nutrients are essential for plant growth, an excess can lead to harmful algal blooms in water bodies, which can produce toxins harmful to human health and aquatic life.

2. What are the main pollutants that can get into my drinking water after a forest fire?

The answer here depends on what was in the area that burned, including natural environment and man-made structures. For example: ash, sediments, and various chemicals from burned vegetation can find their way into rivers, lakes, and reservoirs. These can include nutrients from burnt plants, heavy metals from ash, and organic compounds from burnt trees. On the other hand, testing for pollutants in drinking water from burnt structures can be very complex, including the potential for asbestos release, metals and more. All of these pollutants could affect the taste, smell, and safety of your drinking water.Water Quality

3. I know I need to test – but what do I test for?!

To answer this question, you want to consider the potential sources of contamination in your area.   A great resource to guide you in determining the most suitable parameters would be your local health authority – they are the experts on drinking water quality in your specific area and can help you determine what you might want to keep an eye out for.
Once you have that list in hand, CARO can help you find a cost-effective solution for your needs.   CARO’s Essential Drinking Water Test Kit is often a go-to package, and can be customized based on the needs you have identified with the Health Authorities. To learn more about what you need to test for read our ‘Everything You Need To Know About Impacts On Drinking Water Quality From Forest Fires’ blog post, which will provide you with specific information on private well testing and more!

4. How long will it be until my Boil Water Notice will be lifted?

If your local Health Authority has issued a Boil Water Notice, it is important that you follow their instructions until this notice is lifted.  During this time, your local water purveyor will be working diligently to complete one or more of the following checks and balances to ensure that your water and the system that gets it to you, is safe:

  1. Comprehensive chemical analysis from representative locations within the fire impacted zones.
  2. Physical assessment of the water system looking for indicators of damage.
  3. Isolation of suspected damage areas and leak testing to determine the extent of the damage and the possibility of introducing contamination.
  4. Bacteriological samples from multiple areas in the distribution system over a multi-day period to confirm stabilization.
  5. Operational parameter readings- turbidity, chlorine residual, etc.

In many cases, even after the distribution system is deemed safe and the boil water notice is lifted, long-term monitoring activities will continue to ensure that your water quality does not change as conditions settle.


It is our goal to help make testing accessible to all Canadians, so you can make informed decisions about the quality of the water you consume. From now until the end of October 2023, order your water testing kit through CARO’s online store and receive 30% off your order with the code: carowater2023.

For more information about testing your water, visit our water testing page here.  To order your kit, visit our store here.


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