If you live in Pinellas County, you already know the feeling of walking outside in August and needing a second shower. That same moisture is inside your home too, and it’s what feeds the black specks in your shower grout, the musty smell in the hall closet, and the gray film on your AC vents.
Mildew isn’t a sign that a house is dirty. It’s a sign that a house is in Florida. But it does need regular attention, and the sooner you catch it, the easier it is to clean. Here’s where it hides and how to keep it down, whether you’re in a St. Pete bungalow, a ranch home in Kenneth City, or a family house in Pinellas Park.
Mildew vs. mold: what’s the difference?
Mildew is a surface-level growth, usually gray, white, or black, that sits on top of hard surfaces like grout, caulk, tile, and painted walls. It wipes away with the right cleaner and some scrubbing.
Mold tends to grow into a material rather than on top of it, like drywall, wood, carpet padding, and insulation. It’s often fuzzy or slimy, can be green, black, or other colors, and it usually means there’s a moisture problem behind it, such as a leak or water damage.
Regular cleaning handles mildew well. Mold that’s spread across a large area or into building materials is a different job, covered below.
Where it hides
These are the spots we see most often in Tampa Bay homes:
- Shower grout and caulk, especially in corners and along the bottom row of tile where water sits
- Shower curtains and liners, along the bottom hem
- Window sills and sliding door tracks, where condensation collects when the cold AC meets warm glass
- AC vents and return grilles, which can show dark spots when cool air meets humid air
- Closets, particularly on exterior walls or in rooms with little airflow
- Under sinks, where a slow drip can go unnoticed for months
- The washing machine, especially the rubber gasket on front-loaders
- Ceilings in bathrooms without windows, where steam has nowhere to go
How to keep it down between cleanings
You can’t take the humidity out of Florida, but you can take a lot of it out of your home.
- Keep indoor humidity below 60%. The EPA recommends keeping it under 60%, and ideally between 30% and 50%. An inexpensive hygrometer tells you where you stand.
- Let the AC do its job. Air conditioning removes moisture as well as heat. Setting the thermostat far higher when you leave, or turning it off entirely, lets humidity climb fast.
- Run the bathroom fan. Keep it on during showers and for 20 to 30 minutes after.
- Squeegee the shower. A 30-second pass on the glass and tile after each shower removes most of the water mildew needs.
- Give closets air. Leave a little space between hanging clothes, keep the door open when you can, and consider a small dehumidifier or moisture absorber in a closet that smells musty.
- Fix drips quickly. A slow leak under a sink is one of the most common causes of mold that goes unnoticed.
- Leave the washer door open between loads so the gasket dries out.
Cleaning it safely
For surface mildew on tile, grout, and caulk, a mildew-specific cleaner or a diluted bleach solution, plus a stiff brush, handles most of it. Two rules matter:
- Never mix bleach with ammonia or with acidic cleaners like vinegar. The combinations release toxic gases.
- Ventilate. Open a window or run the fan while you work.
Caulk that has mildew growing inside it, not just on top, usually won’t come clean. At that point the fix is to remove the caulk and replace it.
When it’s a job for a mold professional
The EPA’s rule of thumb is that if mold covers more than about 10 square feet, it’s time to call a professional. You should also call one if mold comes back right after cleaning, shows up on drywall or wood, follows a leak or flooding, or comes with a persistent musty smell you can’t trace. These usually point to a moisture problem that cleaning alone won’t fix, and a mold remediation company is the right call.
When our teams clean, we handle surface mildew on hard surfaces as part of the job. If we see something bigger, like growth on a wall or ceiling or signs of a leak, we’ll point it out rather than scrub over it.
Homes that sit empty
Mildew moves fastest in homes that are closed up for weeks or months, which is why seasonal residents so often come back to a musty smell. If you’re leaving for the summer, our snowbird guide covers what to do before you leave and what to clean when you return. Moving into a home that’s been sitting vacant? Our move-in cleaning guide covers what to clean before you unpack.
A regular cleaning schedule is one of the simplest ways to stay ahead of mildew, because it catches growth while it’s still a quick wipe. Our post on choosing a cleaning schedule can help you decide how often.
Tampa Bay Home Services is a locally owned St. Petersburg company. Every cleaner is a background-checked, bonded W-2 employee. You can read more about how we hire on our Why Us page. We clean homes in St. Petersburg, Kenneth City, Pinellas Park, and across Pinellas County. Get your price and let us take the grout off your list.
This post is part of our complete guide to house cleaning in St. Petersburg.