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WHAT TO DO IF YOUR WELL IS FLOODED

October 04, 2017

Heavy rainfall and flooding can make your tap water unsafe. If you are unsure about the safety of your well water use bottled water, disinfected water, or use both boiled and cooled water for drinking, making beverages or ice, cooking, brushing your teeth, washing dishes, and washing recent surgical wounds. 

Tap water can be disinfected by adding 8 drops of plain unscented household bleach (4 to 6% strength), which is about 1/8 tsp or a dime sized puddle, per gallon of water. If a higher strength bleach is used (8.25% strength), only add 7 drops of bleach. Mix the solution and let it stand for 30 minutes. If the water is cloudy after 30 minutes, repeat the procedure once. Use a container that has a cap or cover for disinfecting and storing water to be used for drinking. This will prevent contamination. Iodine or other disinfection tablets (available at sporting goods departments or stores) may also be used.

If your well has been flooded, please call the Environmental Health division at the Florida Department of Health in Orange County (DOH-Orange) at 407-858-1497 for information on how to sample your water and where to bring the sample for bacteriological testing. If the test reveals bacteria, the well and water system need to be disinfected.

It is important to disinfect both well and plumbing water with unscented household bleach to ensure that all infectious agents (germs) are killed. If you have water treatment devices, remove all membranes, cartridges, and filters; replace with new ones after the disinfection process is completed. 

DOH recommends the following steps to disinfect a contaminated well:

  • If the water is discolored before adding the bleach, run the water until it is clear for up to 10 minutes. If after a while the water does not clear up, wait until you have clear water before proceeding, as this means your well may still be affected by the flooding.
  • Turn off the pump
  • Turn off and then drain your hot water heater, as bleach is not effective in water above 105 degrees. 
  • Remove all membranes, cartridges, and filters. Replace with new ones after the disinfecting process is completed.
  • To avoid adding contamination to the well during disinfection, clean the work area around the top of the well. Then remove grease and mineral deposits from accessible parts of the well head and flush the outside surfaces with 1/2 cup of unscented household bleach in 5 gallons of water.
  • Disinfect the pump. Remove the cap or the well plug on the rubber seal. There are many types of well caps and plugs. If you have questions, contact a licensed well driller. If you have a jet pump, you may also want to contact a licensed well driller for advice on disinfection procedures. 

Consult the bleach chart and pour the recommended amount of regular unscented bleach (4 to 8.25% strength) solution into the well. Try to coat the sides of the casing as you pour. If you get bleach on the pump or wiring, flush it thoroughly with fresh water to prevent later corrosion. 

Well Depth in Feet           Well Diameter in Inches
2”     4”       5”         6”
20’     1 cup    1 cup     1 cup      1 cup
30’    1 cup     1 cup     1 cup      2 cups
40’     1 cup     1 cup     2 cups    2 cups
50’     1 cup     2 cups   2 cups    3 cups
80’     1 cup     2 cups   1 qt         1 qt
100’     1 cup     3 cups   1 qt         1.5 qts
150’     2 cups     1 qt       2 qts       2.5 qts
200’     3 cups     1.5 qts   2.5 qts    3 qts

Conversions 8 oz = 1 cup /16 oz = 1 pint = 2 cups
24 oz = 3 cups / 32 oz = 1 quart / 48 oz = 1.5 quarts
64 oz = 2 quarts / 80 oz = 2.5 quarts / 96 oz = 3 quarts

  • Re-cap or plug the well opening and wait 30 minutes.
  • Turn on and, if needed, re-prime the pump. Open all the faucets on the system one at a time. Start with the ones outside to limit the amount of water entering the septic system, especially if the drainfield area is flooded. Allow the water to run until there is a noticeable smell of bleach. You may also want to flush the toilets. If you have outside faucets, you may want to direct the water away from sensitive plants. If you cannot detect a bleach odor, repeat the disinfecting process.
  • Turn off all the faucets and allow the bleach to remain in the system for at least eight hours.
  • Backwash water softeners, sand filters, and iron removal filters with bleach water.
  • Again, open all the faucets and run the water until there is no bleach smell—for up to 15 minutes. Again, start with the ones outside, close to the well first. This will limit the amount of both bleach and water from entering and possibly effecting the septic tank and drainfield.

IS IT SAFE NOW?
The only way to verify that the water is safe to drink is to have it tested by a certified laboratory. Although chlorine bleach is effective against most microorganisms, it will not remove chemical contamination that may have gotten into your well. If chemical contamination occurred, use commercially produced bottled water until a safe water source is obtained. Contact DOH-Orange for sampling instructions to get your water tested.

For further information, go to http://www.floridahealth.gov/ or contact DOH-Orange at 407-858-1497.