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Fire & Water - Cleanup & Restoration

Mold vs. Rust: How to spot the difference

2/8/2019 (Permalink)

Is it mold or is it rust? That is the question.

Are you able to spot the subtle differences between mold and rust stains? You might see a small red stain and make the assumption that it is rust, but that is not always a safe bet. Before you start any major cleaning efforts, it’s good to be able to identify if that stain is rust, mold, or something else entirely.

Is it normal?

When new stains appear in your home, make certain that they are not the result of infiltrating water or humidity. Try to identify the reason for the stain based on the utility of the room it has appeared in. Mold is found in damp and humid areas, while rust forms during the corrosion of metallic surfaces.

Is it mold or is it rust?

Areas that are typically humid, such as your bathroom and basement, are hot spots for mold growth. If you spot a stain in your shower, sink area or basement that appears to be mold, you are going to want to clean it as soon as possible before it becomes a more pervasive issue. There are different cleaning solutions and methods for cleaning mold, grease, hard water stains and rust. If the incorrect cleaner is used, you may not be able to remove the stain completely.

Recognizing rust

Rust is often identified as a red or reddish brown stain on the surface. It is the end result of the corrosion of a metal containing iron. Rust occurs when water or humid air comes in contact with a surface that contains iron. Areas in your home that are prone to rust include, but are not limited to; water pipes, metal roofing and chimneys, oil tanks for homes equipped with oil heating, electrical panel boxes and nails.

Recognizing mold


The smell of mold is very distinctive. It has a very intense musty, dirty and earthy sent. If you find yourself opening your windows often to alleviate this smell, then you may have a mold problem.


Mold comes in many varieties and there are many different species of mold. It can appear as black spots, grey dust or white and thread-like in areas that have remained excessively damp for long periods of time. If you are unsure of what you are looking at and if it is mold or rust, you may want to call in a professional to perform an inspection just to make sure. When you family’s health is at stake, it is always better to error on the side of caution.

Remediation & Removal

Once you have established that you definitely have a mold problem in your home, it’s time to find a professional mold remediation service. SERVPRO of Northwest Portland is a highly reputable mold remediation resource for the Portland area. We are trained mold damage specialists who get started quickly to get your home back to normal, with specific training and certifications to handle your restoration needs. Call us today for a consultation. 503-283-3658

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