A common mistake made by homeowners is to test their well water without first making sure the water well system itself is clean. Testing water from a dirty well can lead to false positives—the appearance of contamination even when the ground water is clean. A dirty well also can create an environment for contaminants such as certain types of bacteria.
- Is your water well system clean?
A qualified water well system contractor can determine if your water well system needs cleaning by conducting an anaerobic bacteria test, a coliform test, or other tests that can indicate an accumulation of debris in the well.
Anaerobic bacteria can be an indicator of overall bacterial activity in the well—including possibly harmful bacteria. A qualified professional water well system contractor can take a water sample to determine if the amount of anaerobic activity in your well is significant.
While most coliform bacteria are not harmful, they serve as indicators of possible harmful bacteria.
Other possible indicators of a dirty well may be cloudy water, low water flow, or taste or odor problems.
- Cleaning your well system.
If any test results indicate the presence of anaerobic bacteria and/or coliform bacteria—or if you are experiencing cloudy water, low water flow, or taste and odor problems—the National Ground Water Association recommends having your well cleaned by a qualified professional water well system contractor prior to servicing your well system.
A common misconception by homeowners is that chlorine alone will clean a well—the more chlorine, the better. However, chlorine can serve as an effective disinfectant only after debris and other solid material are removed from the well. Well cleaning must remove debris from the well bottom and may require cleaning other components of the well if determined necessary by a qualified professional water well system contractor.
A qualified water well system contractor is equipped to properly clean your water well system. In addition to removing debris from the bottom of the well, the contractor can brush and clean the well casing to remove any accumulation of solid material, and clean and flush the gravel pack around the well and the natural formation (the aquifer) surrounding the well.
Water intakes should likewise be brushed and cleaned. Open borehole wells can be cleaned by carefully jetting the borehole walls to loosen the debris, which can then be evacuated from the well.
Any water treatment devices that are part of your water well system should be checked and serviced according to specifications. A water treatment device that is not regularly maintained can harbor harmful bacteria.
- Testing your well water.
NGWA recommends well owners test the water:
- Annually for bacteria, nitrates/nitrites, and any contaminants of local concern
- More frequently than once a year if there is a change in the taste, odor, or appearance of the well water, or if a problem occurs such as a broken well cap or a new contamination source
- If family members or houseguests have recurrent incidents of gastrointestinal illness
- If an infant is living in the home
- To monitor the efficiency and performance of home water treatment equipment.
You should also check with your local health or environmental health department for recommendations regarding the type and frequency of testing specific to your location.
The presence of coliform bacteria is a possible indicator of a well’s susceptibility to contamination from animal wastes. E. coli is bacteria that originates from wastes such as those found in sewage, and it can result in severe illness. Its presence suggests a contamination source such as a poor performing home septic system in the vicinity of the well that should be repaired or removed by a qualified septic system contractor.
In the vast majority of cases, nitrates come from farm or industrial contamination, or septic systems, and they can be dangerous to your health. Nitrates from fertilizers and septic wastes could be an indication of a local source of contamination or regionally contaminated ground water.
Arsenic and radon are two examples of water quality concerns that can be present on either a local or regional basis. Both can be naturally occurring in an aquifer. Arsenic is a semi metallic element that occurs in rocks and soils—and water that comes into contact with these rocks and soils. Radon is a colorless, odorless, and tasteless gas that comes from the natural radioactive breakdown of uranium in the ground. Exposure to radon can come from two sources: the air in your home, which seeps up through the foundation, and your well water.
(Note: Arsenic and radon are used here as examples only, and may or may not be a problem in your area. Your state may recommend or require testing for certain contaminants specific to your locality. Check with your state or local health department.)
To find state requirements or recommendations for well water testing, visit our State Contacts page.
To find a certified water testing laboratory in your area, contact your state certification officer by visiting the U.S. EPA Web site at www.epa.gov/safewater/labs/index.html.
- Water well system treatment.
Should any contaminants above levels of health concern remain after proper cleaning and disinfection of the water well system, it does not mean you cannot use your ground water. A water treatment device will often resolve any water quality issues.
A qualified professional water well system contractor can advise you on how to proceed. When considering a water treatment device, make sure its specifications match the substances and concentrations you wish to treat. It is helpful to have your water test results when available working with a water treatment service provider.
Information on water treatment options is also available at the Water Quality Association, a not-for-profit international trade association representing the household, commercial, industrial, and small community water treatment industry.