Water and Well Disinfection

Any test which is marked unsatisfactory or unsuitable indicates an immediate need to evaluate and/or disinfect your water system.

Evaluation of the Water System

Prior to disinfection, the system should be evaluated to identify and correct possible sources of contamination. Please Note: Disinfecting the water system without first removing the source of contamination provides only temporary health protection. The following list identifies some of the major health related factors to examine:

• A sanitary seal that prevents surface water, insects, and rodents from entering the well
• A ground surface graded or ditched so surface water drains away from the well or spring
• Well casing surrounded by a concrete slab that extends at least 6 inches above the ground
• Well or spring located at least 100 feet (for well) or 200 feet (for spring) from septic systems, barn yards, or other sources of contamination
• Inverted, screened air vents on the well
• No cross-connection of the drinking water system with a non-potable system such as irrigation water

Disinfecting Your Water

You can disinfect your well with household chlorine bleach such as Clorox, Purex, or a generic brand. The chlorine in the bleach kills bacteria. Note that it may take more than one chlorination for your well to return a satisfactory test. This is generally an overnight process so you will need to plan ahead when you decide to chlorinate. To disinfect your well follow this procedure. If you have a storage tank it may also need to be disinfected.

Professional Help

You may prefer to have a well or water supply professional chlorinate your system. 

Temporary Measures

While waiting for chlorination to be completed, water used for drinking and cooking should be from a known safe supply. You can perform emergency disinfection by boiling the water for 1 minute or putting 4 to 10 drops of bleach into 1 gallon of clear water. Stir and let stand 30 minutes. At that time the water should have a slight chlorine taste, if not, add more bleach. You can also use bottled water purchased from a store, or a known safe water supply.