How to Clean & Disinfect a Basement After Flooding

A brightly lit gray cinderblock wall with dark stains.

Basement cleaning and sanitizing after a flood is an important step in restoring your space. Here's what to do when there's flooding in a basement.

Flooded basements can result from heavy rain, burst pipes or groundwater seepage, leaving behind water damage, mud and potential health hazards. Here's how to clean a flooded basement once the water's gone and your basement is thoroughly dry.

When to clean

Cleaning a flooded basement should begin as soon as water recedes. The faster you act, the better your chances of preventing mold, mildew and bacterial growth. Disinfecting with bleach is recommended immediately after drying, and again after any repairs or replacements.

What should I use to clean a flooded basement?

How to clean a flooded basement

  1. Remove standing water

    Use a wet/dry vacuum or pump to remove as much water as possible.

  2. Clear debris

    Dispose of damaged items, especially porous materials like carpet or drywall.

  3. Dry the area

    Use fans and dehumidifiers to reduce moisture.

  4. Prepare bleach solution

    Mix ⅓ cup Clorox™ Disinfecting Bleach per every 1 gallon of water needed.

  5. Scrub surfaces

    Apply solution and scrub all hard, nonporous surfaces like concrete, tile and sealed wood.

  6. Wait

    Keep surfaces visibly wet for 6 minutes.

  7. Rinse if needed

    For food-contact areas, rinse with potable water. Always follow label directions for use.

  8. Air dry

    Allow surfaces to dry completely before moving items back into the space.

Tips to clean a flooded basement with bleach

  • Know the right bleach-to-water ratio. Check out our handy chart.
  • Use freshly mixed solutions. Bleach loses potency when diluted and stored.
  • Never mix bleach with vinegar, ammonia or other cleaners. This can create dangerous fumes.
  • Wear gloves and ensure good ventilation. Open windows or use fans to circulate air.

Tips for cleaning mold

  • Use Clorox™ Disinfecting Bleach to remove mold stains on hard nonporous surfaces.
  • Let solution sit for 5 minutes before rinsing.
  • Avoid using bleach on porous materials like carpet or unsealed wood.

Household ingredients vs. bleach

Homemade DIY household cleaning solutions may seem appealing, but they often lack the disinfecting power needed after a flood. Clorox™ bleach is EPA-registered to kill 99.9% of germs on hard, nonporous surfaces — making it the best choice for flood cleanup.

Frequently Asked Questions

What’s the best way to disinfect a basement floor after flooding?

Use Clorox™ Disinfecting Bleach diluted with water (⅓ cup per gallon). Apply to hard nonporous surfaces, let stand for 6 minutes, then air dry. This kills 99.9% of germs and protects surfaces from future mold.

Can I use bleach on concrete walls and floors?

Yes. Bleach is safe for sealed concrete and other hard, nonporous surfaces. Avoid using on porous or unsealed materials.

How long should I wait before disinfecting after a flood?

Begin disinfecting as soon as standing water is removed and surfaces are dry. The sooner you clean, the lower the risk of mold and bacteria growth.

Can I mix bleach with other cleaners for stronger results?

No. Mixing bleach with other chemicals like ammonia or vinegar can create toxic fumes. Always use bleach alone and follow label instructions.