How long does it take for mold to grow after a flood? The microorganisms that turn into mold colonies form quickly—usually within 24 to 48 hours.
Billings has been hit with extraordinary environmental challenges in the past few years with the historic flooding of the Yellowstone River and most recently record levels of rain that caused massive flooding and property damage.

Massive flooding in Yellowstone County left behind major property damage and soaked homes.

Flood water can make the air in your home unhealthy. This is because when things remain wet for more than two days, they usually get moldy. Inhaling mold can cause adverse health effects, including allergic reactions.
Mold can and will cause damage to materials in your home and may contain microorganisms, such as bacteria, or chemicals which may affect your health.
Mold begins growing within 24 hours after water enters your home, but it takes a while before you can actually detect a musty mold odor in your home or business.

Heavy rain recently caused flooding in Billings leaving water damage in homes and businesses.
An apartment complex in Billings is submerged after flash flooding rainfall.
The water can seep deep into the ground and saturate nearby buildings causing moisture damage and health risks.
Environmental Medicine Expert, Dr. Krishna Padiyar

“Symptoms of indoor mold can be very similar to allergies, and can include watery eyes, runny nose, sneezing, itching, coughing, wheezing, difficulty breathing, headache, and fatigue,” explained Dr. Padiyar.

Mildew is a specific type of early-stage mold that appears in white and gray patches. In the home, it’s likely to grow in damp areas like basements, bathroom walls, and places with past water damage. 

A solution of water and bleach can be used but after mold becomes apparent on walls and floors, it’s best to call a professional water restoration business for help.

The main difference between mildew and mold is that mildew can be removed with household products, whereas mold requires stronger cleaning agents or professional cleaning restoration service. Just as it is with mold, painting over mildew does not get rid of it either.

Mold can grow quickly on floors and walls if not treated quickly.

It is important to clean your home as early as possible after a recent flood and everything needs to be dried out completely before it is put back into the house. 

“Look for areas of moisture in your home, which may include; flooding, damp basement or crawl space, leaky roof, leaky plumbing, humidifiers, poorly ventilated areas, and/or clothes dryer vented indoors,” said Environmental Medicine Expert, Dr. Krishna Padiyar, MD.

“Be sure to look under carpets at baseboards and even closets as moisture can come in from gaps in between the joists that may not be sealed properly,” said Dr. Padiyar.

As days go by, you may notice peeling paint, cracking and discoloration on walls, which are signs that you have water leaks. When this happens, it creates a haven for mold that becomes visible after some time.

“Testing for molds is very difficult and expensive and cannot determine whether health effects will occur. Mold is normally found outdoors and counts fluctuate from day to day depending on the season. Due to the uncertainties associated with testing for molds, it is not recommended in most cases,” according to Environmental Medicine Expert Dr. Krishna Padiyar.