Mold after a flood can grow on wood, drywall, carpet and furniture that stay wet for more than 24 hours, according to the Environmental Protection Agency (EPA). Start the clock the moment the water is out. Anything wet with flood water that cannot be cleaned and dried within 24 to 48 hours comes out of the house. Hard surfaces get cleaned with detergent and water before any disinfectant touches them. The house then keeps drying for days to weeks until walls and floors read dry.
The steps below follow the four actions EPA lists for flood cleanup: stay safe, sort and throw away, clean, and dry. Flood water can carry sewage and other contamination, along with bacteria, chemicals or other hazards. The information here is general. Anyone with health concerns should talk to a health professional before starting any cleanup work.
The flood-specific sequence comes first. For a visible patch that is still there after the house has dried, see how to get rid of mold.
The First 48 Hours After a Flood Decide What Stays
Wet materials that stay wet for more than 24 hours can grow mold, so the first 24 to 48 hours decide what you keep. EPA says to dry water-damaged areas and items within 24 to 48 hours to prevent mold growth, and it says moisture control is how you control mold.
The Florida Department of Health (DOH) gives a shorter line. It says when water stands for even 24 hours, common molds can take hold, and it advises drying wet building materials and carpets within 24 hours.
The Florida Panhandle health departments issued post-storm mold guidance on October 10, 2026, and the Escambia County health department's post-storm list uses the same 24 to 48 hour line. It says to open all doors and windows when you remove wet or moldy materials or clean moldy surfaces.
EPA lists four actions for flood cleanup.
In practice that means anything wet with flood water that cannot be cleaned and dried completely within that window goes outside for waste removal, and what can be cleaned and dried stays.
- Stay safe as you clean up.
- Sort materials and throw away anything you cannot clean and dry.
- Clean the house and everything in it that was wet or moldy.
- Dry the house and everything in it completely.
Stay Safe Before You Start Cleaning
Stay out of the home until it is safe to enter. EPA says a professional may help determine whether it is safe to enter the home, and flood cleanup can be difficult and dangerous work.
Never run a fuel-powered portable generator inside a home, garage, shed or similar enclosed space. EPA says to use portable generators only outside and at least 20 feet away from buildings. Carbon monoxide (CO) from these generators is a gas you cannot see or smell, and EPA says it can kill you in minutes.
The Escambia County list adds that gas-powered or charcoal-burning equipment should be used only outside, at least 20 feet from doors, windows, vents and air intakes. Symptoms of CO poisoning include fatigue, weakness, shortness of breath, stomach pain, vomiting, headaches, confusion, lack of coordination, vision problems and loss of consciousness. If you suspect CO poisoning, call 911 or the Florida Poison Information Center at 800-222-1222. For the detector side of CO safety, see the carbon monoxide detector page.
People with asthma or a weakened immune system should stay away from moldy sites and not take part in flood cleanup. EPA says children and pregnant people should not take part either.
EPA says to wear the following when you clean up.
- An N-95 respirator
- Goggles without vent holes
- Gloves
- Pants and a long-sleeved shirt
- Boots or work shoes
What to Throw Away and What to Clean
What to throw away after a flood depends on one test: whether the item soaks up a lot of water and cannot be cleaned and dried. EPA says you can usually clean and dry materials that do not soak up water.
Porous materials are the hard calls. EPA says mold can grow on or fill the empty spaces of porous materials, which makes complete removal difficult or impossible. Ceiling tiles and carpet are its examples, and they may have to be thrown away if they become moldy.
Fabrics and textiles are sometimes savable. EPA says you may be able to save some by putting them through the laundry, and a restoration specialist may be able to clean and dry precious items.
For wet drywall, see water-damaged drywall. For wet floors, see water-damaged hardwood floors. The 1, 2 and 3 water classification system is covered on water damage categories.
Cleaning in the Right Order
Clean with water and detergent first, and disinfect only after that. EPA says disinfectants do not work on surfaces that have not been cleaned.
Follow this order for each surface:
Use bleach, if you use it, only after everything wet with flood water is thoroughly cleaned. Never mix bleach with ammonia or with chemicals brought in by contaminated flood water, because the combination can be toxic. Read the product label, dilute in a well-ventilated area, and leave the product on the surface for the contact time on the label.
- Make the first pass gently. Wipe with a cloth dampened with clean water and detergent, and avoid stirring up dust or scrubbing at this stage.
- If you can see mold, clean the visible mold gently before you start any fan or dehumidifier. A running fan can spread it.
- If mold remains on a hard surface, scrub it off with detergent and water and dry it completely, as EPA advises.
- Once a surface is clean and does not absorb water, an EPA-registered disinfectant or sanitizer can be used.
- Afterward, dry tools such as a wet/dry vacuum can remove debris that remains.
Drying the House Takes Days to Weeks
Drying a house after a flood usually takes several days to weeks, according to EPA. Keep air moving even after the floors and walls look dry. EPA says hidden surfaces also need to dry.
Start by opening the house up. EPA says to:
If you have power, fans, dehumidifiers or heaters can speed drying. If you can already see mold, wait to start them until you have gently cleaned the mold you can see at least once, so the fans do not spread it.
Power-driven equipment speeds drying, but outside weather can work against you. EPA says very humid, warm outside air can slow drying. In that case, close the doors and windows and run fans, dehumidifiers, air conditioners or heaters instead. If the flood reached a basement, see the guide to a basement dehumidifier.
Treat the HVAC system separately. EPA says that if any part of it was affected by flood water, do not use it to help dry the house. Cleaning and drying an HVAC system is complicated, so have a professional do it. If the system may be contaminated with mold, do not run it, because it could spread mold through the building. If the system works and is not contaminated, it may help, but most HVAC systems cannot dry a home alone when humidity is very high after a flood. You will likely still need fans, dehumidifiers or heaters.
To judge dryness, use a moisture meter on walls, cabinets and flooring. EPA says materials should read 15% or less before they are ready for refinishing. For a concrete slab, the EPA describes a plastic sheet test. Tape the edges of clear plastic sheeting to the slab and wait approximately 16 hours. If moisture is visible on the sheeting, the slab is still too wet to replace the flooring. EPA says this method is based on an ASTM standard.
Hold off on paint and sealants until the materials are completely dry inside. EPA also says not to seal wall cavities that were flooded.
- Leave outside doors and windows open, if it is safe to do so.
- Open inside doors and cabinets.
- Remove drawers, shelves and built-in furniture so hidden surfaces can dry.
When Mold Shows Up Anyway and When to Call a Professional
If you clean up mold but do not fix the water problem, the mold will most likely come back, according to EPA's mold cleanup guidance for homes. For long-run moisture control, see how to prevent mold.
EPA says that if the moldy area is less than about 10 square feet, roughly a 3 foot by 3 foot patch, you can handle the job yourself in most cases. If there has been a lot of water damage, or mold covers more than 10 square feet, EPA points to its Mold Remediation in Schools and Commercial Buildings guidance, which is written for other building types.
A professional inspector may help decide when you have cleaned up enough, according to EPA.
EPA says to ask a professional about qualifications, training, experience and references. Ask each company about:
- Qualifications
- Training in water damage restoration or mold removal
- Experience drying out buildings
- References
Certifications, Contaminated Water and Who Is Affected
EPA says a qualified professional may have certification, training or experience in water damage restoration, mold removal or drying out buildings. Those professionals may be affiliated with or certified by organizations such as NEHA, AIHA, IICRC or ACAC. EPA does not have a certification program and does not maintain a list of contractors who can perform flood cleanup.
If the water or mold damage came from sewage or other contaminated water, EPA says to call a professional who has experience cleaning and fixing buildings damaged by contaminated water. EPA also says older homes may have building materials that contain asbestos or lead.
Florida licenses mold assessors and remediators through the Florida Department of Business and Professional Regulation, under Florida Statutes sections 468.84 to 468.8424. That is one state's system, so check your own state's rules.
What Mold and Flood Water Can Do to Your Health
EPA says flood water can make the air in your home unhealthy, and breathing in mold can make you sick. Flood water can also contain bacteria, chemicals or other hazards that may affect your health.
EPA says molds produce allergens, irritants and in some cases potentially toxic substances called mycotoxins. Inhaling or touching mold or spores may cause allergic reactions in sensitive people, such as sneezing, a runny nose, red eyes or a skin rash.
Mold can trigger asthma attacks in people with asthma who are allergic to mold. It can also irritate the eyes, skin, nose, throat and lungs of both mold-allergic and non-allergic people. EPA says research is ongoing.
Flood water can bring microorganisms into buildings, including those from sewage. Exposure can cause allergic or irritant effects, and in some cases infectious disease.
According to EPA's brief guide to mold, moisture and your home, it is impossible to get rid of all mold and spores indoors, and spores will not grow if moisture is not present.
This page does not diagnose symptoms or say whether a house is causing a health problem. Anyone with breathing problems, a weakened immune system or other health concerns should talk to a healthcare provider.
Common questions
How long does mold take to grow on wet carpet?
EPA says mold can grow on carpet that stays wet for more than 24 hours. EPA's published guidance gives no longer timeline, while Florida's health department advises drying carpets within 24 hours. EPA also says porous materials like carpet may have to be thrown away if they become moldy.
Can mold grow in water?
EPA says spores will not grow if moisture is not present. The published guidance describes mold growing on wood, drywall, carpet and furniture that stay wet for more than 24 hours. After a flood, the work is drying the materials that held the water.
Can I clean up flood damage myself?
In most cases, EPA says you can handle a moldy area under about 10 square feet yourself. Flood cleanup can be difficult and dangerous, so EPA says it may be best to get help from experienced, qualified professionals. Children, pregnant people, and people with asthma or weakened immune systems should not take part in the cleanup work.
Can I use bleach after a flood?
EPA says to use bleach only after you have cleaned everything that was wet with flood water, using clean water and detergent. Never mix bleach with ammonia or with chemicals brought in by contaminated flood water, because the combination can be toxic. Read the label, dilute in a well-ventilated area, and respect the contact time on the label.
How do I know the house is dry?
According to EPA, materials should read 15 percent or less on a moisture meter to be ready for refinishing. For a concrete slab, moisture visible on taped plastic sheeting after about 16 hours means the slab is still too wet to replace flooring. Keep air moving even after things look dry, since drying usually takes several days to weeks.
Should I run the air conditioner or HVAC to dry the house?
If flood water affected any part of the HVAC system, do not use it to help dry the house, and have a professional handle it. A working, uncontaminated system may help, but most HVAC systems cannot dry a home alone when humidity is very high after a flood. If the system may be contaminated with mold, do not run it.