What to Do When Your Basement Floods
Quick answer: Don’t step into the water until the power to the basement is off. Then find and stop the source, pump or vacuum out the water, and get wet items out to dry. Everything that got wet needs to be dried or removed within a day or two to stop mold.
Safety before anything else
- Keep out of the water while the power is on. Water touching outlets, extension cords, a dryer or a furnace can carry current. Turn the basement circuits off at the breaker only if you can reach the panel from a dry floor. If you can’t, call an electrician.
- Smell for gas. If a gas furnace or water heater stands in the water, or you smell gas, leave the house and call the gas utility from outside.
- Dress for dirty water. Wear rubber boots and gloves. Flood water that came in from outside or up through a floor drain can carry sewage and chemicals.
- Take photos and video. Record the water depth against a wall, the source if you can see it, and damaged belongings before you move them.
Find where the water came from
The source decides how dirty the water is, how fast it will stop, and often how an insurance claim is handled.
| Source | Signs | First move |
|---|---|---|
| Burst pipe or supply line | Spraying or running water, often clear | Shut off the main water valve. |
| Water heater | Puddle spreading from the tank base | Close the cold supply valve and cut power or gas. See water heater leaking: what to do. |
| Sump pump failure | Pit overflowing, pump silent or running nonstop | Check the breaker, the float and the discharge line. |
| Rain seeping through walls | Water along the wall-floor joint or through cracks | Clear gutters and push downspouts away from the house. |
| Floor drain backup | Dark water, sewage smell, rising from the drain | Stop using all sinks, toilets and the washer. |
Basements in the Spartanburg area sit in Cecil red clay, which drains slowly and swells when wet. After a heavy summer storm the soil stays saturated for days and keeps pressing water through cracks and the joint where wall meets floor, even after the rain stops.
Getting the water out
For an inch or two of water, a wet-dry vacuum works. Deeper water calls for a submersible pump with the discharge hose run well away from the foundation. If groundwater is still high outside, pump the basement down gradually over several days. Draining it all at once can let soil pressure crack or bow the walls.
Once the standing water is gone, open windows if the air outside is drier, and run fans and a dehumidifier. Pull baseboards and cut away the bottom of soaked drywall so the wall cavity can dry. Clean and dry or remove wet items within 24 to 48 hours, because that is how fast mold starts on damp materials in a warm house.
What to keep and what to throw out
| Item | Clean water (pipe, heater) | Dirty water (outside flooding, drain backup) |
|---|---|---|
| Carpet | Can often be dried if caught within a day | Throw out |
| Carpet pad | Usually replaced | Throw out |
| Drywall and insulation | Cut out the soaked part | Cut out everything the water touched, plus a margin |
| Upholstered furniture, mattresses | Maybe, if dried fast | Throw out |
| Hard plastic, metal, glass | Clean and dry | Clean, then disinfect |
| Papers and photos | Freeze in zip bags to dry later | Photograph for records; most can’t be saved |
Water that rose from a floor drain or came in from outside is treated as contaminated. Cleaning it up safely is closer to sewage cleanup than to drying out a pipe leak.
When it needs a professional
A wet corner from a single storm, caught the same day, is often manageable with a wet-dry vacuum, fans and a dehumidifier. Call for flooded basement cleanup when:
- Water is deeper than an inch or two, or covers a finished basement
- It came from a floor drain, a sewer line or outside flooding
- Drywall, carpet or insulation got wet and isn’t drying
- The basement still smells musty after a few days
Common questions
It depends on the source. A burst pipe or failed water heater is usually covered. Surface flooding and groundwater seepage usually are not covered by a standard homeowners policy and need separate flood insurance. Sump pump failure and sewer backup are often covered only if the policy has a water backup endorsement.
With fans and a dehumidifier running, a few inches of clean water usually take three to five days to dry. Concrete, block walls and finished basements take longer. Check with a moisture meter rather than by feel.
Clean hard surfaces with detergent and water first. If the water was contaminated, disinfect afterward following the product label. Never mix bleach with ammonia or other cleaners.
Pump out water from a pipe or appliance right away. If the basement flooded because the ground outside is saturated, lower the water a few feet a day so outside soil pressure doesn't damage the walls.
A lingering musty smell usually means something is still damp, such as the bottom of the drywall, carpet pad or wood framing. Mold can grow there where you can't see it.