Shock chlorination is a relatively simple and inexpensive procedure that can quickly eliminate health threats presented by bacterial contamination.

“With little relief in the weather forecast, the cracks in the South Texas ground are beginning to widen, creating countless pathways for contaminants to reach the water table,” said Garrett Engelking, manager of the Refugio Groundwater Conservation District.

In such conditions, waste run-off and septic leaching can more easily access groundwater, resulting in increased incidence of dysentery and cholera, both of which result from the decomposition and seepage of fecal material into the groundwater supply.

Among the most common and more easily detectable bacteria found in wells, iron and sulfur-feeding bacteria can also be eliminated by shock chlorination.

“If not treated, both produce slimes smelling of rotten eggs that can clog pipes and pumping equipment, resulting in reduced water yield, restricted water flow in distribution lines, staining of plumbing fixtures and laundry, damage to water treatment equipment,” Engelking said.

Wells that supply drinking water should be tested for contaminants and shock chlorinated annually. Engelking supplied the following well shocking procedures that will eliminate any microbes or coli form bacteria that have accumulated in domestic water wells.

1. After locating the well head, remove the access or bolts so that the interior of the well casing is exposed.

2. Pour the appropriate amount of liquid chlorine bleach into the well.

3. Attach a garden hose to the nearest faucet and run water back into the well for at least an hour, allowing chlorinated water to circulate through the water in the well.

4. Remove the hose from and close access to the well.

5. Turn on each faucet and allow the water to run until bleach odor can be smelled. Repeat this step with each faucet in the system.

6. Wait 24 hours before using any of the water for drinking or cooking.

7. After 24 hours, flush each faucet until no bleach odor is present, beginning with those outside.

The depth of the well will determine the volume of bleach that is needed. For wells less than 100 fee, use one quart of bleach; wells from 100 to 200 feet, use two quarts or one-half gallon; for wells 200-300 feet, use three quarts; and for wells 300 or more feet, use one gallon.