Drinking well water can cause illness because it is a private source not subjected to the federal regulations that govern municipal water supplies. The safety of private well water falls entirely on the property owner. This lack of oversight means the water is vulnerable to contamination from various sources. The only way to guarantee the water is safe for consumption is through regular testing and, if needed, proper treatment.
Acute Illnesses Caused by Pathogens
Biological pathogens cause acute gastrointestinal illness and are the most immediate health threat from well water. These contaminants are often microscopic organisms, including bacteria like E. coli, and parasites such as Giardia intestinalis and Cryptosporidium. These organisms typically enter the groundwater when the well is compromised by surface runoff, agricultural waste, or a failing septic system nearby.
Pathogen exposure can lead to sudden, severe symptoms collectively known as acute gastroenteritis. Common effects include diarrhea, vomiting, stomach cramps, and a fever, which generally manifest shortly after consuming the contaminated water. While most healthy adults recover fully, the illness presents a greater danger to vulnerable populations who can face severe dehydration and complications. Infants, the elderly, and individuals with compromised immune systems are particularly susceptible to these waterborne diseases.
Giardia and Cryptosporidium are highly resistant to typical chlorine disinfection methods used in public water systems. The cysts of these parasites can survive for extended periods in the environment, posing a prolonged risk to the well owner. If a well is compromised by fecal matter, the presence of total coliform bacteria in a test is a strong indicator that dangerous pathogens may also be present.
Chronic Health Threats from Non-Biological Toxins
Long-term exposure to non-biological toxins in well water poses chronic health threats that often develop without any noticeable immediate symptoms. These chemical contaminants can originate from both natural geological formations and man-made pollution. Since they lack taste, odor, or color, they can go undetected for years unless specialized testing is performed.
Arsenic is a common inorganic contaminant, a naturally occurring heavy metal that leaches into groundwater from surrounding rock and soil. Chronic ingestion of arsenic is associated with an elevated risk of developing serious conditions, including cancer (such as skin, bladder, and lung), heart disease, and diabetes. Another risk is lead, which typically enters the water supply from corrosive water dissolving the metal from older plumbing fixtures or well components within the home.
Nitrates represent another serious chemical concern, often stemming from the overuse of agricultural fertilizers or poorly maintained septic systems. High nitrate levels are particularly hazardous for bottle-fed infants under six months, as the chemical interferes with the blood’s ability to carry oxygen, a condition known as methemoglobinemia, or Blue Baby Syndrome. This acute condition can develop rapidly and can be life-threatening if not addressed quickly.
Essential Steps for Testing and Monitoring Well Water
Because private wells are unregulated, the diagnosis of contamination is solely the owner’s responsibility, making routine testing a mandatory practice. The minimum recommendation is to test the well water at least once every year for total coliform bacteria and nitrates. These annual tests provide a snapshot of the water’s quality and can reveal signs of potential fecal or chemical contamination.
Testing should be performed more frequently, or immediately, if any changes in the water’s appearance, taste, or odor are noticed. Testing is also necessary after any event that could introduce contaminants, including:
- Seasonal flooding.
- A new or repaired septic system installation nearby.
- Significant maintenance or repair to the well itself.
The only way to get a reliable assessment of the water quality is by submitting samples to a state-certified laboratory, which follows strict protocols to ensure accurate results.
Interpreting the basic test results is the first step toward safeguarding the water supply. A positive result for total coliform bacteria suggests that surface water has entered the system, creating a pathway for harmful pathogens. Results showing nitrate levels above the maximum contaminant level of 10 milligrams per liter indicate a need for immediate corrective action, especially in households with infants or pregnant women.
Water Treatment Options for Private Wells
Once testing confirms the presence and type of contaminant, the appropriate treatment system must be selected to remediate the issue effectively. For biological contamination, shock chlorination can be used as a temporary measure to disinfect the well casing and plumbing system. For a persistent problem, a continuous chemical treatment, such as a chlorine injection system or an ultraviolet (UV) light disinfection unit, is typically installed to kill microorganisms.
Chemical toxins and heavy metals require different solutions, often relying on various forms of physical or advanced filtration. Activated carbon filters are highly effective at removing organic chemicals like pesticides and volatile organic compounds, which bind to the surface of the carbon material. For inorganic contaminants like arsenic, lead, or nitrates, advanced systems such as reverse osmosis (RO) are commonly employed.
The RO process forces water through a semi-permeable membrane that blocks the minute molecules of dissolved solids and heavy metals. This system is typically installed at a single tap, known as point-of-use, to provide purified water for drinking and cooking. Successful treatment depends on matching the specific technology to the specific contaminant identified in the testing results.