Well flooded now? If your well and pump has been inundated by flood waters, you should first try to get the well pump restarted to pump out any flood water that has entered the casing. If you do not have electrical skills and experience, leave this to someone who does. Ground Water Science assumes no responsibility and you can be electrocuted. If you have an above-ground pump with air-cooled motor and it has been flooded, assume that the motor is dead and buy a new one of the same size and capacity. If pump box/controls have been flooded, replace those. Seek competent advice on this (maybe or maybe not available at the store). Pro installation is recommended. Once it is safe and the pump is functioning, first divert all flow away from the building's plumbing and the structure (and your neighbors'), then pump to clear the casing and well bore. Pump for several hours at least. This clears flood material. If the pump seizes due to clogging debris, shut it off immediately and clear it. Once pumped clear, disinfect using sodium or calcium hypochlorite intended for use in wells, NOT just any bleach or pool chemical. Follow dosing instructions offered by your health department, but what you need is 100-200 mg/L total chlorine in your well. The amount needed depends on the diameter and water depth in your well, and may range from cups to liters. This EPA page has good pictures. Get it to and below your pump. Let sit 24 hr. Pump off until chlorine is gone. Don't be surprised if pumped water is black or brown. That's the crud in your well. Get the well tested for coliform bacteria. Boil all water used for drinking and cooking until the tests are clear. If this procedure does not decontaminate the well, consult a qualified water well contractor as you have bigger problems.   

Now you can read on: A common consequence of drenching hurricane (cyclone, typhoon) rains is large-scale flooding in coastal areas. In 1999, Hurricane Floyd drenched North Carolina and adjacent U.S. states and caused flooding over large areas. This flooding was environmentally destructive as it breached manure lagoons and drowned large numbers of feedlot livestock, and inundated thousands of wells. The National Ground Water Association was tapped by FEMA to study the aftermath and possible responses. NGWA engaged Ground Water Science to conduct the research due to our hands-on experience in this field, resulting in a report submiited to FEMA in 2002.

Through subsequent hurricane seasons, tsunamis, and other flooding events, up through Katrina, we waited for a sign that FEMA was going to use or distribute the many recommendations provided. The report was never officially published as far as we can tell. It was accepted by them after qualified peer review, so we fail to understand why it wasn't put to use. With the permission of NGWA, we are now publishing it before another hurricane season goes by. Feel free to download this work, paid for by US taxpayers following this link. The report reviews current practice in reactive well disinfection (i.e., after contamination), described field work conducted in North Carolina by Ground Water Science and our contractor, EGIS P.A. (Mike Vaught's company), and offers detailed recommendations for how to set up and implement a local capacity to respond to mass inundation. We hope you find the work useful (but don't wish the circumstances on you, that's for sure) and welcome your comments.

For the "Cliffs Notes" summary version: Go here.