Mold After a Leak: When You Can Clean It Yourself and When to Call a Pro

Published September 25, 2026 · Water damage and mold

You can clean small mold patches yourself, especially if they are less than about 10 square feet and not from contaminated water. For larger areas, extensive damage, or if your heating and cooling system is affected, hire a professional.

Stop the Water First

Before you do anything else, you must find and stop the source of the water. Mold needs moisture to grow. If you don’t fix the leak, the mold will keep coming back.

Once the leak is stopped, dry out any wet materials as quickly as possible. The U.S. Environmental Protection Agency (EPA) says that if wet or damp materials are dried within 24 to 48 hours after a leak or spill, mold will not grow in most cases. Use fans, dehumidifiers, and open windows to help speed up the drying process. Removing the moisture is the most important step to prevent mold.

When to Clean Mold Yourself

You can often handle mold cleanup yourself if the problem is small. The EPA suggests you can clean mold yourself if the area is less than about 10 square feet. This is roughly the size of a 3 foot by 3 foot patch. This applies to surface mold on non-porous materials like hard plastic, glass, tile, or metal. You should also be able to identify the source of the moisture and easily fix it.

If the mold is only on a small, contained area and the water damage is not extensive, you can usually take care of it without professional help. However, you must always take safety precautions.

How to Clean Small Mold Areas Safely

Cleaning mold requires careful steps to protect your health and prevent the mold from spreading. Dead mold can still cause allergic reactions, so it must be removed, not just killed. Here’s how to clean small mold areas:

Safety Checklist:

• Protect yourself: Wear gloves (rubber or non-porous), eye protection (goggles), and a respirator mask to avoid breathing in mold spores. You can find these at hardware stores.
• Ventilate the area: Open windows and doors to get fresh air moving. If possible, use a fan to blow air out of the room.
• Contain the area (optional for very small areas): For slightly larger small areas, you might want to cover nearby items with plastic sheeting.
• Prepare your cleaning solution: Mix a simple solution of detergent and water. Dish soap or a general household cleaner works well. Do not mix chlorine bleach with ammonia or other cleaning products. The EPA warns that mixing these can create toxic fumes that are very dangerous.
• Scrub the mold: Use a stiff brush or a sponge with your detergent and water solution. Scrub the mold off the hard surfaces.
• Rinse and dry: After scrubbing, wipe the area clean with a damp cloth. Make sure the area is completely dry. You can use fans to speed up drying.
• Dispose of materials: Place any moldy porous materials (like rags, sponges, or small pieces of drywall you removed) in a heavy-duty plastic bag. Seal the bag tightly and throw it away with your regular trash. Clean your gloves and tools thoroughly with the detergent solution.

When This Advice May Not Fit

There are specific situations where you should not try to clean mold yourself. The EPA suggests getting professional help in these cases:

• Large moldy area: If the moldy area is more than about 10 square feet (roughly a 3 foot by 3 foot patch).
• Extensive water damage: If there has been a lot of water damage, or if the mold has spread deeply into porous materials like drywall, carpet, or insulation. These materials often need to be removed and replaced by a professional.
• Contaminated water: If the water damage was caused by sewage or other contaminated water, you should always call a professional. This type of water can contain dangerous bacteria and viruses.
• Heating and cooling system: If you suspect mold is growing inside your home’s heating and cooling system (HVAC), you need a professional. Mold in these systems can spread spores throughout your entire home.
• Hidden mold: If you smell a musty odor but cannot see any mold, it might be hidden behind walls or under flooring. A professional can help find and remove it.
• Health concerns: If you have health problems, especially breathing issues or a weakened immune system, you should avoid mold cleanup and hire a professional.
• Structural damage: Never try to repair mold damage that affects the structural parts of your home, such as support beams or subflooring. A qualified professional, such as a structural engineer or a contractor specializing in water damage, should handle these issues.

In these situations, a qualified mold remediation specialist has the right equipment and training to safely and effectively remove the mold. They can also help identify the source of the moisture and prevent future mold growth.

Preventing Mold from Coming Back

The best way to deal with mold is to prevent it from growing in the first place. This means controlling moisture in your home.

Here are key steps to prevent mold:

• Fix leaks immediately: Repair any leaky roofs, windows, or pipes as soon as you find them. Remember the EPA’s guidance: drying wet materials within 24 to 48 hours is key to preventing mold.
• Clean and dry after floods: If your home floods, clean and dry all wet items and areas within 24 to 48 hours.
• Control humidity: Keep indoor humidity levels low. You can use a dehumidifier, especially in damp areas like basements.
• Ventilate: Ensure good ventilation in areas that produce a lot of moisture, such as bathrooms, kitchens, and laundry rooms. Use exhaust fans when showering, cooking, or running the dryer.
• Insulate cold surfaces: Insulate cold surfaces like pipes or exterior walls to prevent condensation, which can lead to moisture buildup.
• Clean gutters: Keep gutters clear of debris to ensure water drains away from your home’s foundation.

By staying on top of moisture issues, you can significantly reduce the chances of mold growing in your home.