Does Your Water Contain an Unsafe Level of Cyanide?

If you’re like me, you probably want to know more about what’s in your family’s drinking water. In this article, we’ll look at Cyanide and the effects it can have on water quality and your health.

Cyanide is a naturally occurring chemical compound used in a variety of industrial processes, including metallurgy, the manufacture of plastics, and the production of chemicals. It typically leaches into our drinking water supply from discharges made by factories that utilize the chemical in their processes. Consuming water containing Cyanide at levels greater than or equal to 0.2 mg/L can cause adverse health effects.

Cyanide is one of the drinking water contaminants regulated by the EPA. This means public water companies are required to monitor their water supply for Cyanide and work to ensure the water they provide their customers does not exceed the legal limit for the contaminant. However, even with this standard in place, it’s still possible for your tap water to contain excessive levels of Cyanide.

How Cyanide Can Affect Water Quality and Your Health

Manufacturing facilities, like steel and fertilizer factories, can produce significant amounts of wastewater. When these facilities discharge or dispose of wastewater, it can cause our water supply to become contaminated with a host of chemicals, including Cyanide.

What is Cyanide, exactly? Cyanide is an inorganic substance that’s typically found together with other chemicals in compounds like Sodium Cyanide and Hydrogen Cyanide.

Some living organisms can produce Cyanide, and it can be found in some common plant-based foods, including almonds, lima beans, soy, and spinach. Exposure to Cyanide can be harmful to your health, but luckily, the amounts of Cyanide contained in the edible portions of these plants are relatively low.

How can drinking water that contains Cyanide affect your health? If you consume water that contains elevated levels of Cyanide over many years, you may develop nerve damage or thyroid problems.

At what level can Cyanide cause health problems? Cyanide is known to cause adverse health effects when its concentration in drinking water is at or above 0.2 mg/L.

In an effort to protect our health, the EPA established legally enforceable standards to limit the amount of Cyanide in our drinking water. Public water companies are required to ensure the concentration of Cyanide in the water they provide their customers is kept at or below 0.2 mg/L.

Given available treatment technology, water utility companies should be able to provide drinking water that meets this quality standard. However, at least one public water system violated the regulatory limit for Cyanide in 2019.

Does Your Drinking Water Contain a Harmful Amount of Cyanide?

Public water companies are required to provide customers with an annual water quality report, also known as a Consumer Confidence Report (CCR). Inside this report, you’ll find important information about your drinking water, including where it comes from, and whether it tested positive for any regulated contaminants like Cyanide.

If you’re curious to know how much Cyanide was found in your city’s drinking water, grab a copy of the latest CCR and look for the section of the report that covers “Inorganic Contaminants.” Here, you’ll find test results for Cyanide as well as other contaminants like Arsenic, Barium, and Cadmium.

How to Interpret Your Water Quality Report

When looking at your water quality report, you’ll see test results for Cyanide reported in Parts per Billion (ppb). 1 mg/L equals 1,000 ppb, so 0.2 mg/L is equivalent to 200 ppb.

Below is an example of what you might see on your annual water quality report if Cyanide is detected in your town’s drinking water:

Example Water Quality Report

MCLG (1)MCL (2)Average
Your Water

Definitions from the EPA:
1. Maximum Contaminant Level Goal (MCLG) – The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety and are non-enforceable public health goals.
2. Maximum Contaminant Level (MCL) – The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to MCLGs as feasible using the best available treatment technology and taking cost into consideration. MCLs are enforceable standards.

In this example, water samples contained an average of 220 ppb of Cyanide, exceeding both the public health goal level (MCLG) and the legal limit (MCL) for the contaminant.

Will You Be Notified If Your Water Contains an Unsafe Level of Cyanide?

In addition to providing you with an annual quality report, your water company is required by the EPA to notify you if they identify a problem with your drinking water.

If your water company delivers water that could negatively impact your health, they have to notify you of the situation within the timeframe set by the EPA. Depending on the severity of the issue, the company is given 24 hours to 30 days to provide this notice.

If your city’s water exceeds the Maximum Contaminant Level (MCL) for Cyanide, your water company will likely be given 30 days to notify you of the violation. Typically, you will receive this notice via the media or through the mail.

What Can You Do to Remove Cyanide from Your Tap Water?

Fortunately, if you want to limit your family’s exposure to Cyanide, there are some effective options for removing the contaminant from your tap water.

But how can you tell which products work and which ones don’t? Well, not all in-home water treatment products can remove Cyanide from your water. However, according to the EPA, certain Reverse Osmosis devices and Ion Exchange systems remove Cyanide from water effectively.

3 steps for selecting the right water treatment system for your family:

  1. Review your area’s annual water quality report to find out what’s in your drinking water.
  2. Determine which contaminants you’d like to reduce from your water.
  3. Select a water treatment product that is third-party tested and certified to work effectively against those contaminants you’d like to reduce from your tap water.

Just remember, no matter which water treatment product you choose, you need to make sure to perform the routine maintenance suggested by the manufacturer. This will help keep the device in proper working order and limit your family’s exposure to Cyanide.



I’ve moved several times over the years, so I know just how stressful it can be to relocate. I want to help put your mind at ease. That’s why I research and write about all the things I think you should consider when moving to a new town.

Recent Content