You may be familiar with the feeling: It’s a hot summer day, and you come in from outside and take off your shoes. Is it just you, or does the carpet feel a little moist?

A significant chunk of the population lives in humid climates, so dealing with moisture in the home can be a bit of a challenge. The battle, however, is not geographically limited. Even if you live in a dry state like Arizona or New Mexico, air conditioners can create condensation, rain can seep in through improperly sealed windows, and leaky pipes can create problems under sinks and behind walls. And all of it can lead to mold.

Penicillium mold on bread

Penicillium mold on bread

Mold can cause untold damage to your home and negatively impact your family’s health. To prevent it from taking hold, you need to control the moisture levels in your home, which can be trickier than you may expect. Let’s unpack the problem, and we’ll share our expert advice.

Pro Tip: We have more on the health risks of mold in our definitive guide to mold allergies. Here’s the moral of the story: You don’t want to be exposed to large amounts of mold for any significant amount of time.

What Causes Moisture in Homes?

There are a few types of household moisture you’ll want to know about. Each has its own causes and solutions to consider.

Atmospheric humidity: All air carries some amount of moisture, and its temperature determines how much moisture it can hold.1 That’s why things feel a little stickier during the summer months. When humidity levels rise, you may notice more moisture accumulation in your home.

Structural leaks: Our homes are designed to keep the weather out, but some homes do a better job than others. Your roof, chimney, windows, and doors could all be sources of moisture if they aren’t properly sealed and installed.

Plumbing problems: Your plumbing system is another major cause of excess moisture in the home. Hot and cold water passes through pipes, which can create condensation. Leaky fixtures can quickly create slimy puddles if they aren’t addressed immediately.

Crawl spaces and basements: Some homes are built over crawl spaces that may not be sealed. If you have an earthen crawl space, water can seep in from the moist dirt and create a repository of humid air below your home. Basements can also be sources of moisture. It’s important they are built correctly and encapsulated completely to prevent that familiar musty smell.

Family activity: Everyone loves a long, hot shower — including household mold. Your own activity may be contributing to the overall level of moisture in it. That goes for cooking and using your clothes dryer too.

Now that we understand some of the sources of household moisture, let’s talk about where it’s most likely happening in your home.

What Areas Are Most Prone to Moisture?

Moisture can accumulate anywhere, but there are a few likely places to look for it. Let’s start with the top of your house and work our way down.

Person holding magnifying glass over a house

Examine your home for signs of mold

The roof: Your roof is the first line of defense against water intrusion in your home.2 If it fails to do its job, you can have a major moisture and mold problem on your hands. Make sure you get your roof inspected for damage at least once a year. For more information on that process, check out our guide to roof inspections.

The chimney: We know you’re not normally sticking your head up your chimney to poke around, but damp chimneys can cause a lot of headaches for homeowners. Damaged flashing, issues with your chimney cap, untreated masonry, and poor ventilation can cause moisture to accumulate.3

The doors and windows: Your doors and windows let light and air into your home, but they might also let in water or allow it to condense in humid conditions. Pay attention to your panes since they’re a bellwether that will let you know if your home is too humid.4

The bathrooms: A lot of water passes through bathrooms, so they’re a major source of household moisture. Hot showers on cold days are nice, but the steam created can cause problems down the road if it’s not addressed. Also beware of bathroom exhaust fans that expel humidity into an attic space (and be sure your duct work is up to snuff).

The kitchen: Your kitchen may be one of the biggest sources of moisture in your home. It’s where you boil water for family spaghetti night, but it’s also where your sink may be leaking or condensation from your refrigerator is accumulating.

The basement: Basements are notorious for letting moisture into homes. A lot of your plumbing terminates there, many homes house their washer and dryer in the basement, and they’re more susceptible to water intrusion than any other part of your home just by nature of being below ground level.5

That’s a good list of places to look for moisture problems in your home, but what happens if you find moisture? Is it always a problem?

How Do I Know If My Home Has a Moisture Problem?

There’s no hard-and-fast rule for when moisture in a home becomes problematic, but the EPA recommends keeping your relative humidity below 60 percent — ideally between 30 and 50 percent6 — to prevent mold growth. Mold loves moisture, and preventing moisture is the best way to prevent mold.

Pro Tip: Try as you might, you’re never going to live in a totally mold-free environment. Mold is everywhere — that’s just a fact of life. Learn more about it in our guide to the most common types of household mold.

You may not know the humidity levels in your home — for that you’ll need a hygrometer — but there are signs that your moisture levels are too high.7

  • Seeing mold
  • Smelling musty odors
  • Seeing condensation on windows
  • Damage to materials such as wood and stucco
  • Not sleeping well
  • Paint seems to be chipping
  • Noticing pests such as cockroaches and silverfish
  • Sweating excessively
  • Allergy flare-ups
  • Food spoils quickly

If you notice some combination of those problems, it’s likely you have a moisture problem that you’ll need to get under control. Luckily, there are some simple steps you can take.

How Can I Control Indoor Moisture?

Controlling indoor moisture may be as simple as opening the windows to allow some fresh air to circulate around your house, or it may be as complicated as installing a sump pump in your basement — it all depends on how severe your problem is. Here are some simple things you can do to start addressing the problem.

Woman looking at black mold on wall of home.

Controlling humidity can help prevent mold in your home.

Indoor humidity: When it comes to humidity, you want to reduce the instances where warm air will interact with colder surfaces. You can do this by increasing the ventilation in your home by opening doors and windows, installing insulation on cold-water pipes, and paying attention to your home’s temperature relative to the outside temperature. The bigger the discrepancy between the two, the more problems you can run into.

Pro Tip: If you live in a humid climate, you’re probably familiar with mold and mildew. What you may not know is that your homeowners insurance likely won’t cover the damage it causes. Read up on the topic in our guide to mold insurance.

If your humidity problem is more severe, you may consider investing in a dehumidifier. Decent single-room dehumidifiers cost between $100 and $300, while entire-home systems may run north of $3,000.8 Remember to either pipe the captured water away from your home or empty the trap regularly. If you don’t, you may create a bigger problem for yourself.

Structural issues: For structural problems like wet basements and leaky roofs, you’ll likely need to call in professionals. There are simply too many factors to go over to provide individual solutions for these issues.

That said, there are some universal things you can do to keep moisture out of your home, including installing weather stripping around doors and windows, installing double- or triple-pane storm doors and windows, encapsulating crawl spaces, and having your roof and chimney professionally inspected.9

As far as your plumbing goes, you may need to call in professionals if you suspect a problem behind your walls or under your floors. For problems you can see, simple solutions may involve tightening junctions, applying plumber’s putty, or purchasing better fixtures.10

Pro Tip: Most new parents are concerned that mold and moisture in their homes may negatively impact their infants. It’s a valid concern, but there’s some misinformation out there. We clear everything up in our guide to mold risks for babies and young children.

You may also consider investing in a leak sensor or three. These simple, relatively inexpensive devices automatically sound when they’re in the presence of moisture, and modern ones can even send an alert to your phone. Invaluable, considering how devastating water damage can be if left unaddressed. Read more about them in our guide to home security systems and their components.

Family issues: Your own behavior may contribute to the excess moisture in your home. Cover pots when boiling water, use an exhaust fan or open a window when taking a hot shower, and make sure your dryer is clean and venting properly to the outside. Don’t crank up your air conditioner on hot days (although it’s tempting!) and wipe up any spills or condensation you notice immediately. And remember: Ventilation is your friend. Keeping the air moving in your home will help prevent moisture from becoming a problem.

Now that we’ve discussed the causes of excess household moisture and potential solutions, we have just a few closing thoughts for your consideration.

Final Thoughts on Moisture in Homes

There are many reasons moisture may accumulate in your home. It’s not necessarily the worst thing in the world if you notice some condensation on your windows in the morning, but it is something you want to pay attention to. If unchecked, excessive moisture in your home can lead to mold growth — something you don’t want for myriad reasons.

If you want to learn more about mold, the problems it can cause, how to clean it, and how to prevent it from coming back, check out our exhaustive guide to household mold. You’ll find everything you need to know and more. In the meantime, stay safe and stay dry.

Household Moisture FAQs

What should my indoor relative humidity be?

To prevent mold growth and the negative health impacts that accompany it, the EPA recommends keeping relative indoor humidity below 60 percent.

Is my house too humid?

If you notice things like condensation on your windows, pipes, or ceilings, it’s likely that your home is too humid. Consider opening doors and windows to improve ventilation or investing in a dehumidifier.

How can I dry my carpet?

Wet carpet can be a homeowner’s nightmare. Immediately clean up excess water and, if possible, aim a fan at the affected area until it’s completely dry. You may need to leave the fan running for additional time to dry out the material beneath the carpet too.

Does humidity cause mold?

Mold cannot grow without moisture, and humidity is a primary cause of damp homes. If your home is too humid, it’s very possible that mold is growing somewhere.

Is mold dangerous?

For healthy adults, minimal exposure to small amounts of mold is nothing to worry about. For young children, the elderly, the immunocompromised, and other vulnerable populations, the risks of moldy environments are increased.