After a hurricane or flood: your well, boil notices and your filters

By the ClearFlow Water team · Updated September 30, 2026 · How we create content

What you do after a storm depends on your water source. On a public system, the utility decides when the water is safe. On a private well, that job is yours. SC health officials put it simply: if you are on public water, “check with your water provider to be sure it is safe to drink,” and if your well was flooded, it “needs to be disinfected and the water tested” (SC Department of Public Health).

Boil-water advisories on city water

A boil-water advisory tells you to boil your tap water before using it, because boiling kills germs that could make you sick (CDC). It is different from a “do not drink” advisory (use bottled water for drinking and cooking) or a “do not use” advisory (use bottled water for everything) (CDC).

While an advisory is in effect, SC DES says to bring water to a rolling boil and “keep it there for at least 1 full minute,” then let it cool, and to use boiled or bottled water for cooking, washing hands, washing dishes and brushing teeth (SC DES). A few points people often miss:

• Boil tap water even if it has been through a home filter or a filter pitcher (CDC).
• Don’t use ice or water from a refrigerator connected to your water line (CDC).
• SC DES also says to stop using ice makers, coffee makers and tea brewers that run on tap water (SC DES).
• If you can’t boil, SC DES says to use unscented bleach with 4 to 6 percent chlorine: “1 teaspoon of bleach to every 4 gallons of water,” then let it stand 30 minutes (SC DES).

Most advisories are local and short. When a main leak put part of Restaurant Row under a precautionary notice in 2022, the City of Myrtle Beach said lifting it “usually occurs within 48 hours” once tests confirm the water is safe (City of Myrtle Beach).

Where local utilities post notices

Not sure which utility you have? It is the name on your water bill.

If your well was flooded

SC DPH is direct about this: “Do not use the water from a flooded well until it has been tested” (SC Department of Public Health). Until then, SC DES says to use bottled water or water you boil for drinking and cooking (SC DES). If floodwater did not reach your well, SC DES says its water “is likely unchanged” and no action is needed (SC DES).

Think about power first. EPA warns not to turn the pump back on until the wiring has been checked by a qualified electrician, well contractor or pump contractor (US EPA). CDC says to turn off all electricity to the well area before clearing debris (CDC). EPA also notes that wells more than 10 years old or less than 50 feet deep “are likely to be contaminated, even if there is no apparent damage” (US EPA).

If your water smells like fuel or chemicals, CDC says boiling or disinfecting will not make it safe; use bottled water and call your health department (CDC).

Disinfecting (shock chlorinating) a flooded well

CDC and NC DHHS recommend having a well contractor or your health department do this (CDC) (NC DHHS Private Well and Health Program). If you do it yourself, here is the SC DES method, in its words where it matters (SC DES):

1. If the water is muddy or cloudy, run an outside spigot until it runs clear.
2. Pour 1 gallon of unscented household bleach into the well casing.
3. Run water from an outside hose back into the casing until you smell chlorine.
4. Open the cold faucets inside and outside until you smell chlorine, then shut them off.
5. Wait 6 to 24 hours. Do not drink, cook, bathe or wash with this water.
6. Run an outside hose into a safe area until the chlorine smell is gone.

EPA adds one step that matters if you have treatment equipment: switch it to bypass before you open the indoor faucets (US EPA). NC DHHS sizes the amount of bleach to the depth and diameter of your well, with a table in its flood guide, and warns that if your well is damaged, the procedure will not work (NC DHHS Private Well and Health Program).

Getting a bacteria test

SC DES recommends testing 7 to 10 days after disinfection (SC DES).

• South Carolina (Horry, Georgetown): pick up a coliform bacteria kit from your local SC DES regional office or health department (SC DES). The sample must be returned the day you collect it (SC DES), and SC DES accepts samples Monday through Wednesday, with results by mail in two to three weeks (SC DES). Questions go to the SC DES Private Well Hotline, 1-888-761-5989 (SC DES).
• Brunswick County: county Environmental Health (910-253-2150) offers a bacteria test that includes total coliform and fecal coliform/E. coli (Brunswick County Health Services, Environmental Health).
• New Hanover County: county Public Health can test well water for E. coli and fecal coliform bacteria (New Hanover County); call On-Site Water Protection at 910-798-6667 (New Hanover County).
• Pender County: Environmental Health samples drinking water for bacterial and chemical contaminants; 910-259-1200 (Pender County).

One clean result is not the end of it. EPA cautions that after a big flood a well “may not be a safe source of water for many months,” so plan on repeat testing (US EPA). Our guide to well water testing in SC and NC covers routine testing once things settle.

Your softener, filters and RO system

A home filter is not a substitute for boiling during an advisory (CDC). Once the advisory is lifted or your well is disinfected, the equipment needs attention too:

• Bypass it first. NC DHHS says to put softeners and household filters in bypass or “out of service” before shock chlorinating, and to have the manufacturer’s cleaning instructions on hand (NC DHHS Private Well and Health Program).
• Sanitize, then reconnect. NC DHHS says to disinfect your softener or household filters “according to the manufacturer’s instructions” and then reconnect them (NC DHHS Private Well and Health Program).
• Replace the cartridges. Michigan’s health department says filters “may have collected bacteria and viruses,” so change the cartridges once a boil advisory is lifted (Michigan Department of Health and Human Services).
• Think like a building manager. CDC’s recovery checklist for health care buildings says to “change pre-treatment filters, backwash carbon tanks, regenerate softener, and clean and disinfect RO membranes,” and to throw out ice from ice machines (CDC). It is written for facilities, but it is a useful home checklist too.

For a reverse osmosis system or whole-house filtration, follow your manual or call whoever services it. If your water still looks milky later, our page on cloudy tap water explains the usual causes.

Power outages and your well pump

If you have an electric well pump, you cannot pump water during an outage (PrivateWellClass.org (RCAP and University of Illinois, USEPA-funded)). PrivateWellClass suggests turning off the pump’s breaker so it doesn’t start on its own when power returns, and notes you can use the water in your pressure tank from a faucet near its bottom in the meantime (PrivateWellClass.org (RCAP and University of Illinois, USEPA-funded)). Before a storm, NC DHHS suggests filling the pressure tank and turning off power to the well (NC DHHS Private Well and Health Program). If the well was flooded, don’t restart it until the wiring has been checked (US EPA).

Numbers to keep handy

• SC DES Private Well Hotline: 1-888-761-5989 (SC DES)
• EPA Safe Drinking Water Hotline: 1-800-426-4791 (US EPA)
• GSWSA: 843-443-8200 (Grand Strand Water & Sewer Authority) · City of Conway utilities: (843) 248-1770 (City of Conway)
• Brunswick County Public Utilities: 910-253-2657 (Brunswick County) · Brunswick Environmental Health: 910-253-2150 (Brunswick County Health Services, Environmental Health)
• New Hanover On-Site Water Protection: 910-798-6667 (New Hanover County) · Pender Environmental Health: 910-259-1200 (Pender County)

Once the water is back to normal

When the advisory is lifted or your lab results come back clean, we’re glad to come out for a free in-home water test. It’s a screening at your tap that shows how your filters and softener are doing. It is not a lab test; for bacteria, nitrate, lead or arsenic, a certified laboratory test is the way to confirm. You can book through our Horry County or Brunswick County pages, or see water testing near you.

Sources

• SC Department of Public Health: Water & Food Safety (storm and hurricane preparedness)
• SC DES: Private Wells: What to Do Before and After Storms
• SC DES: Drinking Water Safety After a Flood
• SC DES: Well Water Quality Testing Services
• US EPA: What to Do After the Flood (EPA 816-F-05-021, updated October 2024)
• US EPA: Emergency Disinfection of Drinking Water (last updated February 24, 2026)
• CDC: Drinking Water Advisories: An Overview (reviewed March 4, 2024)
• CDC: Preventing Crypto at Home During a Boil Water Advisory (July 7, 2025)
• CDC: How to Disinfect Wells After an Emergency (reviewed May 29, 2025)
• CDC: Guidance for Healthcare Water System Repair and Recovery Following a Boil Water Alert or Disruption of Water Supply (reviewed October 24, 2024)
• NC DHHS Private Well and Health Program: Preparing Your Well for the Next Flood (10/2024)
• Michigan Department of Health and Human Services: How to Use Water Filters During a Boil Water Advisory
• PrivateWellClass.org (RCAP and University of Illinois, USEPA-funded): What do I do if there is a power outage and my well won’t work? (March 19, 2026)
• GSWSA: Public Notice - Water Safe for Consumption (September 6, 2019)
• Grand Strand Water & Sewer Authority: home page (office and after-hours emergency number)
• City of Myrtle Beach: Boil Water Advisory in effect for select Myrtle Beach homes (March 25, 2022)
• City of Conway: Public Utilities
• City of Conway: Public Notices
• Brunswick County Public Utilities: Advisories & News
• Brunswick County: Public Utilities (contact)
• Brunswick County Health Services, Environmental Health: Well Water Testing Description
• New Hanover County: Drinking Water Safety
• New Hanover County: On-Site Water Protection (Septic Systems & Wells)
• Pender County: Environmental Health