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How Can I Protect My Well Water from Contamination?

Protecting Your Well from Contamination: Essential Tips and Strategies

SP w carson river 098 10 10 2010

What to do if your well is near a site where contamination was recently discovered

“I just received an alarming letter from my county environmental health department that our property well is near a site where contamination was recently discovered. Our well is our primary source for drinking water. What do we do? Should we be worried?”

First, try not to panic. We realize this can be concerning news, especially when the letter does not provide helpful information, or the language is overly technical and hard to understand. In most cases, private, domestic wells that serve a residential property are often installed to depths much deeper than the source of contamination and draw from a different underground water source (aquifer). To better understand this concept, which can feel abstract since we can’t see underground, let’s look at the graphic below which illustrates what this scenario might look like.

well depthsAn aquitard is a layer of bedrock or other impermeable material that separates different aquifer zones. In most cases, an aquitard will prevent mixing between shallow and deeper aquifers. If the contamination affects the shallow aquifer, and a nearby well is drawing from a deeper aquifer, it’s not likely the same contamination will be found in the deeper aquifer because it’s separated by the barrier of the aquitard.

This graphic is only a generalized view, but it can put into perspective what might be the case for your well. To understand the situation more fully and what it means for your water source, you’ll want to review the installation records for your well. Once you have that information, you can compare your well with the depth of the contamination that was discovered. If you don’t have information on your well and don’t know the depth, the Department of Water Resources (DWR) may have a record of your well in their database. It is state law that geologic logs and pertinent information on all wells drilled in California be provided to DWR.

Next Steps if Your Well is Contaminated

Here are Your Next Steps:

  1. Find your well information and review the design specifics.
  2. Prepare a list of questions - here are some suggestions:
    • Should we stop drinking our water until it can be tested?
    • How did you determine this contamination is a threat to our water source?
    • Who will pay for testing?
    • Who is the consultant hired to mitigate the contaminated property?
    • How can I get records and status updates on the cleanup?
  3. Call the person at the environmental health department who sent the letter for more information.
  4. Call an environmental cleanup agency or consultant for an independent assessment of the situation.

What if the site has been identified as a source of contamination

When a site has been identified as a source of contamination, one of the first requirements from the oversight agency handling the case is to conduct a well survey, which is a tool to identify all the wells within a given radius from the source (usually ½ mile). The caseworker will analyze the survey and identify which wells could be affected by the contamination based on their construction and the distance from the source. The next step is usually obtaining permission from the well owners who could be affected to test the water from their well. 

Right now we are consulting for a property owner who had a small farm in the family. Underground storage tanks (USTs) were used at the farm for fueling equipment and vehicles. Although the USTs were removed in the 1980s, they leaked, and fuel was released into the surrounding soil and groundwater. A neighbor who lives in a house next door draws water from a private well on their property and is within proximity to the source of contamination. Although their well is constructed to draw water from a deep zone at 300 feet, their well has a screen that extends through the shallower aquifer where contaminants have been discovered in groundwater samples. We’ve tested samples from the well at least twice per year since 2007, and none of those samples showed traces of contaminants. It is the responsibility of the land owner or responsible person of the contaminated site to provide for testing, and relay the results to the well owner.

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It can be daunting to receive a letter with such alarming news, but arming yourself with information and asking the right questions will go a long way toward helping you feel safe about the integrity of your water. We have over 40 years of experience dealing with government agencies and cleaning up environmental messes - we can help you. Give us a call at (831) 475-8141 or click the link below for a free consultation.