Safe drinking water and proper wastewater treatment is important. Flooding presents special health risks and requires extra attention for private wells and septic systems.
If your well has been flooded, you need to disinfect it to protect your family's health. Floodwaters carry bacteria, viruses, and parasites, as well as chemicals. Diseases such as dysentery, hepatitis and giardiasis can be transmitted through private wells that have been contaminated by floodwaters. Chemicals such as pesticides, solvents and petroleum-based products also pose health risks.
Sediment that enters your well during flooding can cause problems for the pump and plumbing systems. Bacteria that cause a rotten egg smell and stain plumbing fixtures may also be introduced during flooding.
Disinfection kills living organisms but will not remove other chemicals or sediment. The Center for Disease Control (CDC) and the Minnesota Department of Health (MDH) recommend that you bring the water to a rolling boil and boil it for at least one minute. Cool before use. Do not contaminate water with dirty utensils, hands or containers after boiling. Household treatment systems do not provide adequate protection against disease and should be disinfected. Water softeners and water heaters should also be disinfected.
If floodwaters covered the top of your well, you need to disinfect the well and household plumbing. If you have a shallow sandpoint or driven well and floodwaters approached it — even if it was not inundated — you should disinfect to make sure the water is safe to use. After disinfection, test the water supply to make sure you have completely eliminated disease-causing organisms. Use a lab certified by the Minnesota Department of Health.
Shock chlorination of a private well is relatively simple, but a contractor or plumber could be hired. To guarantee disease-causing organisms are completely eliminated, they must be exposed to chlorine at a high enough concentration for an adequate length of time.
Taking care of your septic system to help it recover from flood damage is important, too. First, pump the septic tank and distribution box as soon as possible after the flood to remove silt and debris. Also, don't compact the drainfield by driving or using heavy equipment on it. Saturated ground is especially susceptible to compaction.
Review all electrical connections and wiring BEFORE turning the electricity back on. Also check to make sure the manhole cover is secure and the inspection ports are not damaged or blocked.
Finally, check the drainfield area for erosion or animal damage. If needed, repair erosion damage. Sod as soon as possible if the vegetation over the septic tank or drainfield has been destroyed. If sewage has backed up into the house or garage, thoroughly disinfect the area, because disease-causing organisms in wastewater present a serious health threat.
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Information provided by the University of Minnesota