Can Mold Grow After a Water Leak is Fixed?

Yes, mold can grow after a water leak is fixed, and here are some reasons why:

1. Residual Moisture

Water can seep into building materials during a leak so water damaged building materials must be properly dried or replaced to prevent mold growth. As such, how porous the building materials are, how long they have been moist, and how much moisture is actually in them can all effect the likelihood of mold growth.

2. Lack of Ventilation

Poor ventilation can contribute to elevated humidity levels which makes mold growth more likely.

3. Improper Moisture Detection

Oftentimes water leaks can affect areas such as behind walls that aren’t visible on the surface. Proper moisture detection using a moisture meter is required in order to ensure that all of the moisture is properly detected and taken care of.

mold in bathroom

How to Check for Mold After a Water Leak or Water Damage

Checking for mold is not as simple as many people think, so here’s a guide on how to do it properly.

Do a Visual Inspection

Mold needs moisture to grow so if you find where the moisture is in your property, then you can find where the mold is likely to be. We recommend checking corners, underneath carpets, behind furniture, ceilings, walls, and pretty much anywhere else you can think of for discoloration or water stains. Keep in mind that mold can take on various colors, so don’t just write it off as something else if it’s not black.

Do an Odor Inspection

Mold often produces a musty and earthy smell. Follow your nose to locate areas that have that distinct odor.

Use Mold Testing Kits

There are two types of mold test kits that you can use at home and below we will discuss both of them.

Surface Tests: These kits allow you to collect samples from various surfaces which you can then send to a lab for analysis.
Air Tests: These kits can capture mold spores from the air for lab analysis.

Use Moisture Meters

Sometimes moisture can be hidden in places like behind walls where you can’t see it. Moisture meters are great for detecting difficult to find moisture which could be the source of mold growth.

Seek Professional Help

If you suspect that there is a mold or moisture issue in your property, it’s a good idea to contact professionals like us for a more thorough inspection. Call us now for a free mold inspection and quote!

How Long Can Mold Grow For After a Leak is Fixed?

All mold needs is moisture and a food source to grow so it can continue to grow as long as the water damaged areas contain moisture.

How Fast Does Mold Grow After a Water Leak?

Mold can start growing within 24-48 hours of coming into contact with moisture.

Does a Water Leak Always Mean Mold?

A water leak doesn’t always guarantee that mold will grow, but it significantly increases the risk of mold growth. It all depends on the environment of the property and how quickly and thoroughly the leak and resulting water damage was taken care of.

Is Mold Dangerous?

Yes, mold is generally dangerous to your health and property, but the amount of risk posed by mold will vary depending on how toxic the type of mold present is, how much mold there is, how sensitive you are to the mold, and the duration of the mold exposure.

Here are some points to consider when evaluating the potential dangers associated with mold:

Allergic Reactions and Respiratory Issues

Allergies: Mold spores can trigger allergy symptoms like sneezing, runny nose, itchy eyes, and skin rash.
Asthma: For people with asthma, inhaling mold spores can lead to an asthma attack or worsen existing symptoms.
Respiratory Infections: In some cases, mold can lead to respiratory infections. This is especially likely in people with compromised immune systems.

Toxic Mold

Mycotoxins: Some types of mold produce mycotoxins which can lead to more health problems such as neurological issues and inflammation. The infamous “black mold” (Stachybotrys chartarum) is one such type of mold that produces mycotoxins.

Other Concerns

Mold is a decomposer by nature so it will gradually break down the building materials in your property which leads to structural damage over time. This damage is both hazardous to your health and expensive to repair.

Does Mold Die When it Dries Out?

Mold does not “die” when it dries out; it goes dormant. While mold spores require moisture to grow and multiply, they can survive for a long time under dry conditions.

In this situation when the moisture becomes available again, the dormant spores can reactivate and begin to grow and multiply. This is why simply drying out an area where mold has grown is generally not sufficient for long-term mold control. To effectively deal with mold, you need to remove it physically and prevent future moisture problems.

Top 4 Types Of Mold to Look Out For After Water Damage

Certain types of mold are more likely to grow after water damage. Here are the top 4 types of mold to look out for in your property:

1. Stachybotrys Chartarum (Black Mold)

This is the infamous “toxic black mold” that produces mycotoxins which are harmful to humans. It often grows on high-cellulose/low-nitrogen surfaces like drywall, paper, and wood. It appears black or dark green.

2. Aspergillus

Commonly found indoors, this mold can appear in various colors and can potentially produce mycotoxins. It frequently grows on walls, insulation, and clothing.

3. Penicillium

Known for its blue or green color, this mold often grows on materials like wallpaper, insulation, and furnishings that have been exposed to water. It can spread easily and may cause respiratory issues or allergic reactions.

4. Cladosporium

This type of mold can grow in both warm and cool conditions and is commonly found on wood and textiles. It is usually dark green, brown, or black and can cause respiratory problems.

How to Prevent Mold Growth in My Water Damaged Home?

Remove Water Damaged Materials: Any materials that are water damaged should be removed and replaced if they can’t be adequately dried and cleaned.

Dry the Area: Use fans, dehumidifiers, and other drying methods to thoroughly dry the affected area.

Clean and Disinfect: Use appropriate cleaners and disinfectants to clean the area where water damage occurred.

Ventilate: Make sure the area is well-ventilated to help remove moisture and fumes from cleaning agents.

Inspect for Hidden Moisture and Water Damage: It might be necessary to open up walls or lift carpets to check for hidden moisture or mold. A moisture meter can also help in doing this.

Consult Professionals: For extensive water damage or mold, it may be best to consult professionals like us for proper cleanup and restoration help.

Monitor: Keep an eye on the area over time to ensure that mold does not grow again.


Given the right conditions mold can grow even after a water leak is fixed. That’s why it’s important to call a professional like us as soon as possible if you have a leak in your property. Call now for a free quote!