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South Carolina Well-Water Risks After a Flood

After a flood, drinking water in wells can become contaminated in several ways. Here's what South Carolina residents should know about well water risks after a flood.

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After a flood subsides in South Carolina, the problem is no longer having too much water. Instead, the issue is about water quality.  

Flooding has a direct impact on private wells, causing homeowners to have unsafe drinking water. Find out how flooding affects well water and learn what you can do to protect your drinking water. 


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What Type of Contaminants Are in Floodwaters?

During a flood, the water will carry the contaminants of whatever it touches. The types of contaminants will vary by location, but floodwaters could contain toxic or dangerous substances. Frequently, floodwaters contain sewage from septic systems or treatment plants, bacteria such as E.coli or coliform, and chemicals such as car fluids or industrial waste. 

With so many dangerous contaminants, contact with these waters can cause rashes, vomiting, gastrointestinal illnesses, and infections of open wounds. The CDC recommends anyone who touches floodwaters should wash their skin with soap and water as soon as possible. 

How Can Flooding Contaminate Your Well?

Water readily mixes with itself, and if a flood reaches the well in your yard, the well is likely contaminated with whatever was in the floodwater. This means the water coming out of your faucet has the same health risks as the floodwaters in the streets. 

The flooding doesn’t even need to come in direct contact with your well for it to become contaminated. Because of how groundwater moves below the surface of the soil, a well’s drinking water could be contaminated if it reaches the same groundwater tables as a nearby flood. 

Learn more about what could be in your water after a flood with this EPA guide to sources of well water contamination.

Has Flooding Affected South Carolina’s Well Water?

Yes, private wells from Greenville to Charleston have been affected by flood contamination. For example, during the 2018 hurricane season where flooding overwhelmed so many parts of the state, an estimated 134,595 wells in South Carolina were potentially affected by flood contamination, according to the National Ground Water Association. 

However, even though the geography of impact can be wide, well water testing can be uncommon. After Hurricane Matthew in 2016, South Carolina’s Department of Health and Environmental Control only tested 74 private wells. Residents may have sought out well testing from other sources, but this number is still shockingly low. 

Of the South Carolina wells that were tested after the 2016 hurricane flooding, 41 percent had coliform and eight percent had E.coli.

8 Steps to Protect Your Well Water After a Flood

The owners of private wells are responsible for their safety, and these eight steps can help you address water quality concerns after a flood. 

1. Test your well. 

The only way to know exactly what’s in your well water is to send it to a lab for analysis. For help, call the EPA’s Safe Drinking Water Hotline at 1-800-426-4791 or learn more about South Carolina’s well testing services.

2. Run water until clear.

Follow guidelines from the water testing lab, and when you’re ready to disinfect your well, the first step is to flush out any sediment by running the water in an outside spigot until it’s clear. 

3. Shock well with bleach. 

Each well head is designed slightly differently. Use manufacturer’s guidelines to remove the well cover and pour the recommended amount of bleach into the well casing. Next, cycle the bleach through the system by using an outdoor hose and adding water into the casing until you smell bleach coming from the hose. 

4. Populate the lines, wait, and flush system.

To kill any bacteria lurking in your pipes, run the cold water in each faucet until you smell bleach, and then shut the faucets off. Wait six to 24 hours without using the water. Afterward, run the water from an outdoor hose until you no longer smell bleach in the water. 

5.  Re-test water.

Test your well water about seven to 10 days after disinfection. Testing too early could give you a false reading that your water is safe. Any risks from remaining bacteria would need time to repopulate to detectable levels. Take a long-range view for well safely and re-test your well every few months to ensure that contamination from nearby flooding hasn’t leached into the groundwater or your well.

6. Don’t use septic systems immediately after a flood.

A functioning septic system relies on dry soil. Using a septic system during a flood could cause sewage to back up into your basement. Always follow the recommendations of a plumber or safety inspector for when your plumbing is safe to use. 

7. Drink bottled water until you are certain water is free of contaminants.

Prioritize safety by drinking bottled water. Well water contamination can cause serious health issues, and you may have other property issues to deal with, such as foundation repairs, improving drainage, or installing a sump pump

8. Get a professional foundation inspection to identify damage.

Flooding can cause hidden damage to the structure of your home, weakening it over time, reducing its market value, and affecting the home’s livability. For example, mold can start to grow in just 24 to 48 hours of wet conditions, and if water shifts the soil below your home, a process of differential settlement could start where your home tilts, bows, or cracks. 

Learn how you can protect your home with a free inspection from the basement and waterproofing experts at Mount Valley Foundation Services.

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