How Do You Know If You Have Mold in Your House?


A staggering 1.5 million species — that’s how many species of fungi there are in the world. Of these, 300 species are pathogenic — meaning, they can cause disease in humans, animals, and plants.

Some genus of molds, such as Aspergillus, are part of that list of pathogens.

What’s more, many of these harmful molds are everywhere in nature.

Unfortunately, that can include your home. After all, researchers found that 47% of US homes have had dampness issues or mold problems.

The big question now is, how do you know if you have mold in your house? What are the signs of mold in a house that you should be on the lookout for?

Most importantly, what should you do if you do find these fungal species at home?

This post will get to the bottom of all these concerns, so be sure to keep your eyes glued to this page!

A Quick Biology Lesson on Molds

On their own, molds (and their spores) are microscopic, making them invisible to the naked eye. They play essential roles in the environment, such as breaking down organic matter.

Although many mold species are ubiquitous, they — and their spores — can lie dormant for a very long time. However, the right conditions, such as an indoor relative humidity (RH) of 70%, can spur them to life. Pair that with dampness and the presence of organic material, and they’re sure to grow and spread.

In such cases, it can take as little as one to two days for molds to proliferate. The longer you leave them undisturbed, the more time they have to multiply and spread. Give them enough time, and they can take over massive areas of your home.

If this happens, you’re looking at some of the most expensive home repairs you could ever deal with.

So Then, How Do You Know If You Have Mold in Your House?

Have you seen patches of white, brown, orange, purple, green, or black on your walls, floors, or ceilings? If so, then these are surefire signs of mold in your house.

That said, one of the easiest steps on how to spot mold is to give your home a complete surface inspection.

One huge caveat though: if you can already see a lot of these patches, it likely means you have a serious mold issue. That’s why it also pays to know the common causes of indoor molds. This way, you can address them right away before they trigger a whole-house mold invasion.

In any case, here are the other signs, indications, and causes of indoor mold.

The Smell of Your Home Makes Your Nose Wrinkle

If your home smells a bit like a gym locker, old bread, or used socks, chances are, you have molds at home. These foul smells are more noticeable when you first enter your home (or a room). The odors may also be more discernable when your AC or heater cycles on.

Recent Water Intrusion

Water damage claims are some of the most common property damage claims. All 50 states, after all, have had at least two instances of major flooding within the past decade. The frequency and rate of high-tide floods have also doubled within the last 30 years.

As if the water damage isn’t bad enough, it can also give rise to mold growth. Again, molds are very simple organisms — they can survive and thrive with enough moisture. So, if you’ve had a recent water intrusion problem, it’s likely that molds are growing in your home.

Water Leaks

Water leaks in the average US household waste more than 10,000 gallons of water every single year. Aside from the waste they bring, such leaks can also raise your home’s indoor moisture levels. This, in turn, encourages the growth and spread of mold spores.

If you have minor plumbing issues like leaky faucets, get those fixed ASAP. This will help keep your home’s indoor dampness at a minimum.

Be sure to also check your water bill. If it went up without an actual increase in your water usage, it’s likely that you have plumbing leaks. With the use of leak detection technology, a plumber can pinpoint where those leaks are.

People at Home Seem to Always Be Down With a Cold

One in 10 people in the US suffers from mold-related allergies. Worse, half of these people can catch other illnesses due to their allergies.

Molds have also shown to trigger at least four in 10 of all asthma attacks in US households. Even in minute amounts, mold spores can be very dangerous to people with asthma or allergies.

What if no one in the fam is allergic or asthmatic though?

Chronic exposure to mold spores can still trigger cold-like symptoms in healthy folks. At the very least, inhaling mold spores can result in eye irritation, sneezing, or a runny nose. In some people, dry cough or skin rashes may also develop.

Your Headaches Are Growing in Frequency and Severity

If your head has been hurting more often (but just at home), take that as one of the possible signs of black mold exposure. Do note that many types of molds are black though. The term “black mold”, however, often refers to mold species that release mycotoxins.

Mycotoxins, in turn, have shown to cause a plethora of ailments, including headaches.

Get Rid of All Those Patchy Growths Now

There you go, all the possible answers to the question, “how do you know if you have mold in your house?” If you’ve noticed any of the signs above, it’s best to get your home inspected before your mold issues go out of hand.

The sooner you can figure out what’s causing your mold issues, the sooner you can correct them. Prompt mold removable not only keeps pricey home repairs at bay — it also makes your home safe and livable again.

Speaking of livability, here’s a solid guide on DIY home improvement ideas that you may want to check out!

About Author

LaDonna Dennis

LaDonna Dennis is the founder and creator of Mom Blog Society. She wears many hats. She is a Homemaker*Blogger*Crafter*Reader*Pinner*Friend*Animal Lover* Former writer of Frost Illustrated and, Cancer...SURVIVOR! LaDonna is happily married to the love of her life, the mother of 3 grown children and "Grams" to 3 grandchildren. She adores animals and has four furbabies: Makia ( a German Shepherd, whose mission in life is to be her attached to her hip) and Hachie, (an OCD Alaskan Malamute, and Akia (An Alaskan Malamute) who is just sweet as can be. And Sassy, a four-month-old German Shepherd who has quickly stolen her heart and become the most precious fur baby of all times. Aside from the humans in her life, LaDonna's fur babies are her world.

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2 years ago

Thank you for your advice. Mold in the house is terrible, and it is worth reacting quickly if you lead the first signs. I used this article when I wanted to determine if I had mold in my air ducks