How Fast Does Mold Grow After a Water Leak?

Have you recently dealt with a water leak? If so, you might be worried about mold.

In the presence of excess moisture — often as a result of a water leak — mold can begin to proliferate indoors on surfaces such as drywall, plywood, and tile.

One of the main concerns homeowners have about mold is that it can cause significant damage to buildings.

As mold grows, it breaks down wood and other organic materials, resulting in both structural and cosmetic damages.

Exposure to certain species of mold can also be dangerous to your health. Common mold-related symptoms include headaches, fatigue, rashes, allergic reactions, and other respiratory problems.

Proper moisture control is the key to preventing unwanted mold growth from damaging your home and your health. If your home has recently suffered any water damage, you should take steps to prevent mold from growing.

How Fast Does Mold Grow After a Water Leak?

There are many factors that contribute to the speed of mold growth. For example:

  • Temperature and humidity
  • Presence of mold spores
  • The species of mold
  • Types of surfaces affected

A general rule of thumb, according to the EPA and the CDC, is that mold can start to develop on surfaces within 24 to 48 hours of water exposure.

However, at this stage the mold spores are not easily visible to the naked eye. It usually takes around 18 to 21 days for the mold spores to colonize and become apparent.

Under favorable conditions, mold can begin to grow as quickly as a few hours. That’s why it’s so important to act quickly in the event of a water leak or flood.

Furthermore, mold releases spores into the air as it grows, which can spread to other surfaces that have been exposed to moisture.

Do Water Leaks Always Result in Mold Growth?

Any water leak carries the risk of mold growth, but that doesn’t necessarily mean that mold growth is certain.

The chance of mold depends on many factors, such as the severity of water damage, how quickly it was cleaned up and dried, and the extent of surfaces affected.

After a water leak, you should always remove any excess water or moisture as quickly as possible. Any affected surfaces should be thoroughly dried within 24 hours.

If excess moisture in your home is left unchecked for longer than 48 hours, there is a good chance that mold will grow.

According to the EPA, if you are not able to thoroughly dry your home within 24 to 48 hours after a flood, you should assume that you have mold growth.

How to Prevent Mold After a Water Leak

There are several precautions you can take to lower the chance of mold growth:

  • Fix leaks and remove excess moisture as quickly as possible.
  • Remove any water-damaged materials or items that can’t be cleaned or completely dried.
  • Use an air conditioner or dehumidifier to keep humidity levels as low as possible.
  • Allow air to circulate by using fans or opening doors and windows.

Keep in mind that moisture after a leak or flood can be hidden in walls or flooring.

A common mistake that many homeowners make is cleaning and drying only the visible surfaces after a leak. They neglect any water or moisture that may be trapped within the walls or underneath floorboards, giving mold ample space to grow undetected.

When Should You Call a Mold Professional?

Any and all indoor mold can be a potential threat to your health and should be promptly removed, regardless of the appearance or species.

If you have more than 10 sq. feet of visible mold growth (roughly about a 3 ft. x 3 ft. patch) in your home, the EPA recommends using a professional to assess and remediate the problem.

Per NYC’s Local Law 55 (the “Asthma-Free Housing Act”), mold is a health hazard and must be handled using safe work practices. These safety requirements include sealing and isolating the work area with plastic sheeting and properly disposing of mold-contaminated materials.

If there are more than 10 square feet of mold in a building with 10 or more units, Local Law 55 requires the landlord to hire both an NYS-licensed mold assessment firm and an NYS-licensed mold remediation firm to fix the problem.

About Green Orchard Group – Licensed Mold Experts in NYC

Green Orchard Group has 25+ years of experience providing trusted environmental health & safety services. Our services include mold testing, assessment, and remediation by licensed and knowledgeable mold specialists.

For help with mold or water damage in New York City or the Tri-State Area, call (212) 219-8261 or send us a message today!