Is That Mold? Or Just Water Damage?

If you’ve moved into a new home or apartment and found some areas of discoloration on the ceiling or walls, you may be wondering if it’s mold or just old water damage. You could ask the previous owner, or your landlord, but they may not give you a straight answer, especially if you haven’t signed the lease yet.

At My Pure Environment, we have the tools and the know-how to ensure the air you breathe at home is clean and free from mold and pathogens. We want to impart some of that knowledge to you today and help you decide whether that stain on the ceiling is mold or just water damage.

What’s the difference between mold and water damage?

Mold and water damage are related in that, where there’s one, you’ll almost always find the other. The primary factor in determining whether or not mold is going to grow is moisture. Indoor molds prefer to grow on the more fibrous building materials, like wood and drywall. When parts of your home become damp, they are a perfect food source for mold to begin growing.

Water damage doesn’t always result in mold growth however. If the area is dried and treated within an appropriate amount of time, mold spores may not have a chance to take root. Minerals in the water will still leave a stain, and that’s why it’s sometimes hard to tell whether or not the discoloration you’re seeing is mold.

How do I tell if it’s mold or not?

There’s a simple way to tell if you’ve got a mold problem. Just remember the Three S’s. Smell, Shape, and Shade.


One way you can sometimes tell is by the smell. Occasionally you can smell mold before you see it. By the time a mold colony has grown large enough to be visible, the air will have been saturated with spores and might smell damp, musty, or earthy.

Just because the air doesn’t smell moldy, doesn’t necessarily mean that there isn’t mold. So let’s look at another way to tell the difference between mold and water damage.


Water damage will form in a shape that resembles water droplets. Because of the surface tension properties of water, any stains resulting from water damage will resemble pooled or flowing water. Keep in mind that mold forms where there is moisture, so it could be that colonies have formed in a similar shape or pattern.


Water damage is usually visible because the minerals in the water leave a stain. The color of the stain can vary from brown to reddish brown. Mold is typically more of a darker brown, tending towards black, with bits of green or bluish-green.

There are mold varieties that are reddish brown in color, so this shouldn’t be used as the only method in determining whether the spot is water damage or mold.

Contact a Mold Inspection Specialist in Santa Clara, CA

Don’t gamble with your health. We can help you determine whether you’re dealing with old water damage or a harmful mold infestation. If you’re unsure, contact one of our mold experts at My Pure Environment for a free consultation.

Photo used under creative commons license – commercial use (11/16/2020) Atomicdragon136 (WikiMedia Commons)

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