Recently constructed or recently repaired wells must be disinfected to prevent bacterial growth in the well and in the plumbing system.  Also, if routine bacteriological testing reveals the possibility of contamination, then well disinfection is recommended.

WELL DISINFECTION PROCEDURES FOR THE HOME OWNER:

1.  Locate the wellhead and remove an access plug or bolt so that the area within the well
     casing is exposed
2.  Using a funnel, pour in an appropriate amount (see table below) of liquid chlorine bleach.
     A concentration of 50 parts per million is recommended.
3.  Using the nearest hose tap and a garden hose, allow water to run through the funnel into
     the well for two or three hours.  This will circulate the well water and facilitate the
     bactericidal action by allowing all fittings and equipment in the well to be exposed to
     chlorine solution.
4.  At this point, you may flush the system and collect another sample for bacterial analysis
     of the well itself, but we recommend that you extend the disinfection process throughout
     the entire plumbing system.
5. To disinfect the remainder of the plumbing system, go to the next available faucet and let
     it run until the bleach odor can be detected.  Continue this process throughout the
     plumbing system at each faucet.  Allow the chlorinated water to sit in the plumbing
     system at least overnight, and it is recommended that the highly chlorinated water remain
     in the system for 24 hours.
6.  The next morning, flush all faucets until the bleach odor disappears and the water is
     clear of any debris or color.
7.  You may now submit another bacteriological sample to determine if the disinfection
     process was successful.

REMEMBER:  Well systems, especially shallow wells, hand-dug wells and old wells are subject to more bacterial contamination.  A single disinfection may not be sufficient and you should periodically submit bacteriological samples to check water quality.  If your doctor suggests that gastric cramps or chronic diarrhea may be caused by contaminated water, you should immediately disinfect the well and submit samples for analysis.

                                          DOSAGE TABLE FOR CHLORINE BLEACH *

             * These dosages are approximate.  Greater amounts are recommended for
                excessively turbid water or for hand-dug wells

Information is provided by:
                      Wichita Falls City - County Health Laboratory
                      1700 Third Street in Wichita Falls, Texas  76301