Well Water Contamination

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Most of us don’t have to think much about where our water comes from. Of the roughly 120 million households in the US, the vast majority get their water from municipal waterworks, which are responsible for keeping the potable water supply clean and safe. Still, a significant minority of those homes (about 13 million) rely on private wells as a water source.

A well is an ancient technology which is essentially a hole in the ground for getting access to groundwater. Safer and more convenient than surface water, water from a well has hopefully made its way into the local aquifer by filtering through a thick layer of soil, leaving behind contaminants and pathogens. Often, wells work as well as they always have. Various types of pollution, however, can disrupt this natural process of filtration, adulterating the groundwater and making wells unsafe for drinking.


The Problem

Well water contamination is highly dependent on local context. A given well’s proximity to a variety of manmade structures and human activity will make all the difference as to its vulnerability to contamination.


Contamination by Pathogens

Biological contamination can take the form of bacteria, viruses, or water-borne parasites. These microorganisms normally populate the earth’s surface and, as mentioned above, the soil normally filters them out by the time the water reaches the aquifer. This can go wrong in various ways.

Sometimes surface water can pool beside an improperly sealed well and seep down along the liner or casing, thus providing a direct route for pathogens to reach a well.
Sometimes a flooding event will overtop a wellhead and flood water will contaminate the well from above.

A properly made septic drain field should not contaminate a well, but in some cases, a badly made or badly located septic system can introduce pathogens into groundwater. Agriculture activity can sometimes contaminate local groundwater, as in the case of the manure lagoons used by massive hog farms to dispose of tons of fecal material.


Heavy Metal Contamination

Heavy metals like lead, mercury, or arsenic can get into the groundwater from a variety of sources. Industrial activities like mining, refineries, and cement production sometimes release dangerous levels of heavy metals into the water. Leach water from landfills can contaminate wells with heavy metals. Depending on local geology, even naturally occurring heavy metal contamination can be a problem.


Nitrates and Nitrites

Agricultural runoff from chemical fertilizers as well as the above mentioned hog lagoons are a major source of excess nitrogen. This runoff ends up not only in people’s wells, but in rivers and ultimately the oceans, contributing to algae blooms and the dead zones that devastate marine ecosystems.


Chemical Contamination

A wide variety of industries can release chemicals into the environment that end up in groundwater. Petrochemical plants that make products like inks and dyes, plastics, pesticides, solvents, and pharmaceuticals have been a source of chemical contamination. Underground storage of gasoline and other chemicals can leak into groundwater. Inadvertently consuming these toxic compounds can lead to serious health problems in the long term.


How to Protect Yourself

Thinking about all the things that can affect your water supply can be scary, but there are some things you can do to mitigate the risks.



Testing is the first line of defense against drinking water contamination. Getting your water tested will tell you whether you have anything to worry about and help you determine what steps to take if there is a problem.

The EPA suggests getting your well water tested every year. Whether you want to test this often is up to you, but you should certainly get a test done if:

- There has been a problem with wells nearby
- There has been a recent flood or new industrial activity nearby
- You do any work to your well
- You notice anything strange about your tap water


Shock Treatment

If you have biological contamination in your well, and it came from a contaminating event, rather than an ongoing, chronic source of contamination, shock chlorination can be a good strategy.

Shock chlorination of a well requires nothing more than common 5% concentration, unscented household bleach. The bleach must be added to a well at a rate of 3 pints per 100 gallons of water storage.

To determine the amount of water storage, find the distance in feet from the surface of the standing water in the well to the bottom of the well. Multiply that distance by how much water is contained in one foot of well casing. For standard 6 inch well casing, this is about 1.5 gallons.

Run a garden hose from the house to the wellhead. Add the appropriate amount of bleach and run the hose straight into the wellhead for about 15 minutes after you start to smell bleach coming out of the hose. Run each fixture in the house until you smell bleach coming out. Turn off all water and allow the chlorine to work for 12-24 hours before flushing the system until the smell of chlorine is gone.


Shock treatment is effective for occasional problems with pathogens that get into a well. If you want to protect yourself against the ongoing risk of pathogens or other contaminants in your well water, a high quality water filter is an excellent solution.

With the Berkey water purification system, you are protected from all the contamination mentioned above, and more! The three facets of the Berkey’s water filtration system provide total protection against more than 200 kinds of contaminants. The Berkey can take water from nearly any well and turn it into safe, delicious drinking water. Experience the peace of mind that comes from knowing that no matter what happens with your well, you and your family are protected.


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