Why Does Carpet Smell Musty a Year After Getting Wet?
Last updated October 26, 2026
The short answer
Trapped Moisture in the Padding
When carpet gets wet, the padding underneath absorbs water like a sponge. If the water was not fully removed within the first day or two, the padding can stay damp for months. The surface carpet may dry, but the padding remains a hidden reservoir of moisture.
That damp padding becomes a perfect place for mold and mildew to grow. Over time, the mold releases a musty odor that seeps through the carpet fibers. Even if you clean the surface, the smell keeps coming back because the source is underneath. The only real fix is to remove the wet padding and often the carpet itself.
- Check the carpet padding by lifting a corner and feeling the underside.
- Press your hand on the carpet; if it feels cool or damp, moisture is present.
- Look for dark spots or stains on the padding, which signal mold growth.
- A musty smell near baseboards may indicate water in the tack strips or subfloor.
- If the padding is wet or moldy, it must be removed, not just dried.
Moisture in the Subfloor
Water can soak through the carpet and padding into the plywood or concrete subfloor below. Wood subfloors absorb water and dry very slowly, especially in humid climates. If the subfloor never fully dried, it can harbor mold for a year or more.
The subfloor may look dry on the surface, but moisture can be trapped in the wood grain or between layers. A moisture meter used by the pros can detect hidden dampness. If the subfloor is affected, it may need to be dried with specialized equipment or replaced if the wood is rotted.
- A lingering musty smell often comes from the subfloor, not the carpet.
- Wood subfloors can take weeks or months to dry, even with fans.
- Mold on the subfloor can spread to walls and baseboards.
- If the subfloor is rotted or warped, it may need to be removed.
- The pros can test moisture levels and decide if the subfloor can be saved.
Mold Growth in the Carpet Fibers
Mold can grow directly on the carpet fibers if they stayed damp long enough. The backing of the carpet, which is often made of latex or jute, is especially vulnerable. Once mold takes hold in the backing, it is nearly impossible to remove completely.
Cleaning the surface with shampoo or steam may remove some mold, but spores can remain deep in the fibers. The musty smell is a sign that mold is still active. In many cases, the carpet and padding must be removed and replaced to get rid of the odor for good.
Humidity and Airflow in Your Home
If you live in St. Petersburg, the humid subtropical climate means outdoor air is often moist. That humidity can keep a damp carpet from drying fully, even long after the original water event. Without good airflow, moisture stays trapped and mold thrives.
Running air conditioning, using dehumidifiers, and opening windows when possible can help reduce indoor humidity. But if the carpet is already moldy, lowering humidity alone will not remove the smell. You need to address the source of the moisture and the mold itself.
What the Pros Usually Do
When you call local water damage pros, they start by inspecting the carpet, padding, and subfloor for moisture and mold. They use moisture meters and sometimes infrared cameras to find hidden dampness. Based on what they find, they may recommend removing the carpet and padding, drying the subfloor, and treating any mold.
The work usually involves pulling up the carpet, discarding the wet padding, and drying or replacing the subfloor. They may also treat the area with antimicrobial solutions. After that, you can install new carpet or choose a different flooring. The goal is to remove the source of the smell, not just cover it up.
Water damage does not wait
Every hour counts once water gets into floors and walls. One call starts the response.
Call Now (727) 308-5518Frequently asked questions
Can I just use baking soda to get rid of the musty smell?
Baking soda can absorb some odors, but it will not fix the underlying moisture or mold. If the padding or subfloor is still damp, the smell will return. You need to find and eliminate the source of moisture first, then clean and dry the area thoroughly.
How do I know if the carpet needs to be replaced?
If the carpet padding is wet, moldy, or smells musty, it should be replaced. Carpet with mold in the backing is also hard to save. If the subfloor is dry and the carpet is not heavily contaminated, professional cleaning might work, but often replacement is the safer choice.
Will a dehumidifier help with the musty smell?
A dehumidifier can help reduce indoor humidity and make the area less hospitable for mold. However, if the carpet and padding are already saturated, a dehumidifier alone will not dry them quickly enough. You still need to remove the wet materials and address the subfloor.