Well water potability sampling/testing ensures the quality meets the state and or local requirements and the safety of the home's well water supply. Water quality testing of well water regularly is an essential part of maintaining a safe and reliable source. Well water test results allow homeowners to address the specific problems of a water supply. Testing helps ensure that the well water source is being properly protected from potential contamination, and that appropriate treatment is selected and operating correctly.
Well water testing may include checking for coliform bacteria and E.Coli (Escherichia coli), nitrates, manganese, pH, arsenic, and more. Typically, water tests include taking a sample close to the pump, before the water goes through a treatment system. The sample is then sent to a laboratory for analysis to determine whether additional treatment is necessary. Well water potability sampling is outside of the scope of the home inspection as it is not part of the standard of practice.
EPA regulates public water systems; it does not have the authority to regulate private drinking water wells. Approximately 15 percent of Americans rely on their own private drinking water supplies, and these supplies are not subject to EPA standards, although some state and local governments do set rules to protect users of these wells. Unlike public drinking water systems serving many people, they do not have experts regularly checking the water’s source and its quality before it is sent to the tap. These households must take special precautions to ensure the protection and maintenance of their drinking water supplies.
City Water
If you live in the city you are most likely receiving your water from a municipal water supply (city water). One of the biggest concerns of a municipal water supply is bacteria. Municipalities will control the presence of bacteria using disinfectants, most commonly chlorine for its ability to kill the bacteria and maintain its presence as water is traveling miles to its destination. Chlorine isn't foolproof, though, and neither is the infrastructure. Boil water advisories are not uncommon and are the result of a potential concern or failure in the disinfection system.
Well Water
Those of you who live outside of the service area for public water supplies have your own private well. In Texas, an initial test for bacteria is required when the well is constructed. Also, mortgage companies will require a potability test to be done before any lending on the property is available. Because this is your own water supply, you are responsible for your water's safety. Water testing is relatively inexpensive and you should have your water tested for bacteria as well as other basic parameters such as lead, nitrates, and arsenic. It is recommended to have this test done yearly.
To keep your well safe, you must be sure possible sources of contamination are not close by. Experts suggest the following distances as a minimum for protection — farther is better (see graphic on the right):
Many homeowners tend to forget the value of good maintenance until problems reach crisis levels. That can be expensive. It’s better to maintain your well, find problems early, and correct them to protect your well’s performance. Keep up-to-date records of well installation and repairs plus pumping and water tests. Such records can help spot changes and possible problems with your water system. If you have problems, ask a local expert to check your well construction and maintenance records. He or she can see if your system is okay or needs work.
Private, individual wells are the responsibility of the homeowner. To help protect your well, here are some steps you can take:
Have your water tested periodically. It is recommended that water be tested every year for total coliform bacteria, nitrates, total dissolved solids, and pH levels. If you suspect other contaminants, test for those. Always use a state-certified laboratory that conducts drinking water tests. 
Since these can be expensive, spend some time identifying potential problems. Call today for a consultation from Michael Hoff your InterNACHI inspector for information about how to go about water testing.
Testing more than once a year may be warranted in special situations if:
