How DHEC Recommends Treating Your Well Water Once a Year for Bacteria

Why You Should Test and Treat Your Well Water Annually

If your home or business depends on a private well for drinking water, you're not alone—many South Carolinians rely on private wells as their main water source. But unlike public water systems, private wells aren't regularly monitored by the government. That means the responsibility for keeping your water clean and safe falls squarely on your shoulders.

The South Carolina Department of Health and Environmental Control (DHEC) strongly recommends testing and treating your well water at least once a year—especially for bacteria. One of the most common contaminants is coliform bacteria, which includes E. coli. These microorganisms don’t always make water look or smell bad, but they can cause serious health issues, particularly for young children, the elderly, or those with weakened immune systems.

What to Test For

Over time, even a well that’s been functioning perfectly can develop issues. Rain, runoff, cracked well caps, and nearby septic systems can introduce bacteria into your groundwater source without warning.

DHEC recommends an annual water quality test, specifically for:

• Total coliform bacteria
• E. coli
• Nitrates and nitrites
• Lead and arsenic (depending on your area)

But even if your water tests clean, a yearly shock chlorination is still a smart preventive measure. Think of it as a deep-cleaning for your well—a way to kill off any bacteria that might have settled in without yet causing trouble.

What Is Shock Chlorination?

Shock chlorination is a method of disinfecting your entire well system using household bleach (chlorine). It helps eliminate bacterial contaminants that might be hiding in your well casing, plumbing, pressure tank, and even in your home’s pipes.

According to DHEC, the ideal time to shock your well is once a year, or:

• After repairing or opening the well system
• If your water has a sudden odor, taste, or cloudiness
• If a recent test found bacteria

What You'll Need

Before you get started, gather the following:

• Unscented household bleach (5–6% sodium hypochlorite)
• A clean garden hose
• Rubber gloves and eye protection
• A large bucket
• Access to the top of the well

You’ll also want to avoid using your water for 12–24 hours after treatment, so plan accordingly.

Step-by-Step: How to Shock Your Well

1. Turn Off Power to the Pump

Start by turning off the electricity to your well pump at the breaker box to ensure safety while working near water.

2. Mix the Chlorine Solution

Use about 1 gallon of bleach per 100 feet of well depth. Mix it with several gallons of water in a large bucket. For example, if your well is 200 feet deep, you’ll need about 2 gallons of bleach.

3. Pour the Solution into the Well

Remove the well cap and carefully pour the chlorine-water mixture into the well casing. Take your time—splashes can damage wiring or parts inside the casing.

4. Recirculate the Water

Turn the power back on. Connect a clean hose to an outdoor spigot and run water from the house back into the well for 30 minutes to circulate the chlorine through the system.

5. Open Faucets

Turn on all indoor and outdoor faucets one by one until you smell chlorine. Once all faucets smell of bleach, turn them off. Don’t forget to flush toilets and run water through appliances like dishwashers and washing machines.

6. Let It Sit

Let the system sit unused for at least 12 hours. This gives the chlorine time to disinfect every part of your plumbing.

7. Flush the System

After the waiting period, run your outside hose or faucet (not into your septic system!) until the chlorine smell disappears. This may take several hours. You can then flush your indoor faucets too.

After Treatment: Retest Your Water

About 7–10 days after shock chlorination, it’s important to retest your well to ensure the treatment worked and your water is bacteria-free.

You can obtain testing kits through the DHEC, your county health department, or certified private laboratories. If bacteria are still present, a second chlorination may be necessary, or it could be a sign of a larger issue, such as a cracked well casing or a nearby contamination source.

When to Call a Professional

If you’re unsure about doing this yourself or if your test shows ongoing contamination, it’s a good idea to call a licensed well contractor or water treatment specialist. They can inspect your well, recommend necessary repairs, or install a long-term disinfection system, such as a UV light or chlorinator.

Clean Water Is Worth the Effort

Taking care of your private well isn’t difficult, but it does require some attention. Annual testing and shock chlorination can prevent illness and protect your family’s health. Even if your water looks and tastes fine, bacteria can be invisible—and dangerous.

By following DHEC’s guidelines each year, you're staying ahead of potential problems and ensuring your water stays clean, fresh, and safe for everyone under your roof.

Need Help with Well Water Treatment in South Carolina?

If you're in South Carolina and need assistance with disinfecting your well or testing for bacteria, please give us a call. We provide well inspections, water testing, shock chlorination, and full well pump services to homeowners across the state.

Protect your health—get your well checked today!