What We Wish Everyone Knew About Well Water Testing After A Flood

Posted on January 28, 2022

At the end of 2021, many cities and municipalities across British Columbia were hit by devastating floods, mudslides, and rainstorms.  Many individuals were displaced due to these extreme weather events and are slowly being allowed to return home. Among the many factors to consider when inspecting the fitness of your home after a flood event, the safety of private drinking water systems including wells should not be overlooked.   But what exactly are you looking for?

Look no further (OK fine, we’ll stop), as CARO is here to help guide you through drinking water testing after a flood.  Make sure you follow along all the way to the end, where we have provided a discount code for 30% off our private well water testing kits available through CARO’s online store.

Why should I test my well water after a flood or large environmental event?

Testing your private well water is an important part of returning home after an event such as a flood, rainstorm, or mudslide to ensure the safety of yourself and your family. These major environmental events can cause damage to water sources and your well which could lead to immediate and long-term health impacts.  Contaminated run-off and microbial or bacterial contamination are two major sources of concern that should be addressed.

Part of assessing the risk of possible contamination is looking for a change in colour, odour, and clarity, but just because your water may look safe, does not mean it is.  Many of the most harmful water contaminants are not visible to the naked eye, which is why soliciting the help of your local water testing laboratory is a smart first step in returning home.

What should I be testing my well water for?

There are two main categories of contaminants you should be testing your well water for: Bacteriological Testing (the little living critters that can make you sick), and Chemical Testing.

1.  Bacteriological testing

Many of us have seen the images of cattle being let through floodwaters, and brave neighbours navigating flood rivers to help save people and livestock.  Now, imagine that same water entering your private drinking water source, carrying with it all the little critters that once lived on that cow or on the bottom of that boat.

A basic drinking water test, including Total Coliforms and Escherichia coli (E.coli) is a good indicator of whether or not this contamination has entered your private water source.  E.coli in particular can be harmful to humans and cause illnesses such as nausea and diarrhea. When E.coli is present in water, it is not safe to drink until further measures are taken to eliminate this bacteria from the water.


2.  Chemical Testing

Many of the impacted areas in British Columbia are areas where farming and similar agricultural operations were commonplace.  Run-off from agricultural properties may bring with it some unique contaminants that should be considered when designing your testing program:

Anions and Nitrates – High levels of nitrates can be  caused by fertilizer run-off into private well systems from farms and agricultural operations. Unfortunately, nitrate has no color, taste, or odor, so detecting its presence can only be done by testing your water.   Additional anion testing CARO provides include chloride, fluoride, nitrite, and sulfates.

Metals – Metals can be found in contaminated run-off from soil, rocks, and other elements. Consumption of water with heavy metal contamination can have long-term health impacts. CARO tests for a variety of metals in drinking water, including elements from Aluminum to Zirconium.

Each of these categories of chemicals play an important role in the agricultural industry, from controlling pests to increasing yield and providing the public with access to local produce. Where you do NOT want them, is in your drinking water.  If your well has been impacted by flood water, as indicated by a basic bacterial drinking water test, it may be helpful to consider a more comprehensive testing regime that includes other sources of contamination that are common in your area.  If you need help with this one, our team of scientists is happy to help find the perfect balance of testing – contact us at [email protected] to chat with a scientist today.

What happens if the water tests come back positive for contamination?

Most things are OK in moderation, so it is always important to compare your data to the Guidelines for Canadian Drinking Water Quality (or, because scientists love acronyms, the GCDWQ).  Our drinking water quality reports come complete with comparison to these guidelines, so you don’t have to go combing through the tables yourself.  If your tests come back with contaminants that exceed the GCDWQ, it is important to contact an environmental professional in your area for guidance on next steps.

Positive tests results of bacterial contamination of well water is somewhat common, and means you need to disinfect your well.  A filtration system installed in your well pipe system, under sink water filter or a countertop system work well to help filter the contaminants out of the water, or there are other chemical approaches (iodine, chlorine bleach, etc.) that are best discussed with a professional.

How do I test my own well water?

The contaminants listed above can all be detected using CARO’s at-home water testing kits. The Essential Drinking Water Test Kit, for example, covers total coliforms, E.coli, anions, total metals, and the general chemical makeup of your water.  All our kits come with easy-to-follow instructions and can be delivered right to your door.

Our goal is to empower Canadians to make informed decisions about the quality and safety of their water. For a limited time, use the code CAROCARES through our store (, to save 30% off all our water testing kits. If you have questions about how to get started on testing your well water after a flood, rainstorm, or any other environmental event, reach out to Team CARO via email: [email protected], or call 1-888-311-8846.

Order your kit here, and for more information on water testing, visit our water testing page.


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