Mold in an apartment is common, and it is also easy to make worse by cleaning it the wrong way. A small patch on a bathroom wall is a different job from mold spreading across a ceiling, and the difference matters for your health, your deposit, and who should pay for the fix. This guide follows the approach used by the U.S. Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention (CDC): find and fix the moisture first, clean small patches safely, and get help for anything larger. For more rental advice, browse our Apartment Guides.
TL;DR: How to Get Rid of Mold in an Apartment
- Fix the moisture first — mold will come back unless the leak, humidity or ventilation problem is solved.
- Small patches (under about 3 ft × 3 ft / 10 sq ft) on hard surfaces can usually be cleaned by the tenant, with gloves, an N95 mask and goggles.
- Scrub hard surfaces with detergent and water, dry them fully, and throw out porous items such as mouldy carpet, ceiling tiles and soft furnishings you cannot clean.
- Tell your landlord in writing as soon as you find mold, especially if it is large, spreading, or caused by a leak or building fault.
- Prevent it coming back by ventilating, keeping indoor humidity below 60%, and drying wet areas quickly.
1. What Causes Mold in Apartments?
Mold needs only two things: moisture and something to grow on. In apartments, the moisture usually comes from one of four sources.
Leaks are the most serious cause: a dripping pipe, a leaking roof, a faulty window seal, or water coming through from the apartment above. Condensation is the most common cause, especially in bathrooms and bedrooms — warm, moist air hits a cold wall or window and leaves water behind. High humidity does the same job more slowly, particularly in summer or in apartments with poor airflow. Poor ventilation makes all three worse, because damp air has nowhere to go.
Mold grows on almost any damp surface: painted walls, grout, wood, plaster, fabric and paper. It does not need light, and it does not need a flood. A bathroom that never dries out, a bedroom with the windows always shut, or a kitchen with a slow leak under the sink are all enough. If your apartment also smells musty, see how to get rid of smell in an apartment — mold is one of the most common causes.
2. How to Tell If It Is Mold — and Mold vs Mildew
Mold usually appears as black, green, brown or grey spots or patches, often with a musty smell. Mildew is a type of surface mold: it is usually white or grey, powdery, and grows on damp surfaces such as shower grout and window frames. Mildew is generally easier to clean, but it still means there is too much moisture in that spot.
You do not need a mold test kit to decide what to do. If you can see a patch, smell a musty odour, or notice damp, peeling paint or bubbling wallpaper, treat it as mold and act on the moisture. Testing rarely changes the advice: clean small patches, fix the moisture, and get professional help for large areas.
Be cautious about colour alone. Black mold is not a single species, and a black patch is not automatically more dangerous than a green one. What matters is the size of the affected area, whether it keeps growing, and whether anyone in the home has asthma, allergies or a weakened immune system.
3. Can You Clean It Yourself? The Size Rule
The EPA guidance used by most housing advice is straightforward: if the moldy area is less than about 10 square feet — roughly 3 ft × 3 ft — you can usually clean it yourself, provided you are healthy, you wear the right protection, and the mold is on a hard, non-porous surface.
Clean it yourself when: the patch is small, on tile, glass, metal, sealed wood or painted plaster, and you can find and fix the moisture source.
Do not clean it yourself when: the area is larger than 10 square feet, mold is inside walls or ceilings, it keeps coming back after cleaning, it followed a flood or sewage leak, or anyone in the home has asthma, severe allergies, or a weakened immune system. In those cases, tell your landlord and ask for a professional.
If you are unsure, take a photo, measure the patch, and send both to your landlord. That gives them the information they need to decide, and it creates a record that you reported it promptly.
4. Step-by-Step Safe Cleanup for a Small Patch
Do this only for a small patch on a hard surface. If the area is larger, skip to the landlord section below.
1. Protect yourself. Wear rubber gloves, an N95 respirator mask and goggles. Open a window for ventilation, and keep other people and pets out of the room while you work.
2. Prepare the area. Lay old towels or plastic sheeting under the patch to catch drips. Do not dry-brush, vacuum or sweep mold — that spreads spores into the air.
3. Scrub with detergent and water. Use warm water and household detergent, or a commercial mold remover made for hard surfaces. Scrub the patch and a margin around it, then rinse with clean water. The EPA’s guidance is to scrub mold off hard surfaces with detergent and water and dry the surface completely — that is the core of the cleanup.
4. Dry it completely. This step is as important as the scrubbing. Wipe the surface dry, then ventilate the room or run a fan or dehumidifier until it is fully dry. Mold returns quickly to a surface that stays damp.
5. Throw out what you cannot clean. Porous items — mouldy carpet, ceiling tiles, soft furnishings, books and cardboard that have been soaked — usually cannot be cleaned properly. Bag them, seal the bag, and dispose of them. Do not keep a mouldy item because it looks clean on the surface.
6. Clean your tools and wash up. Wash the cloths you used, or throw them away. Wash your hands and face, and ventilate the room for at least an hour.
What Not to Do
Do not present bleach as the recommended mold killer. Bleach can discolour surfaces, irritate lungs and eyes, and it does not reliably remove mold from porous materials — and it can make the problem look solved while mold remains underneath. Detergent, water and thorough drying are the safer, recommended approach for small hard-surface patches. Never mix bleach with ammonia or other cleaners. And do not paint over mold to hide it: paint traps moisture underneath and the mold will grow through it.
5. When to Tell Your Landlord — and What to Say
Tell your landlord in writing as soon as you find mold, even if the patch is small. In most tenancies, the landlord is responsible for structural damp, leaks, faulty plumbing and building faults, while the tenant is responsible for day-to-day ventilation and cleaning. Reporting early protects both sides, and it is the only way a leak above you or inside a wall gets fixed.
Send a short written message — email is best, so there is a record — with: where the mold is, how big it is, a photo, when you first noticed it, and anything you know about the cause, such as a leak or a window that does not close. Ask them to inspect it and to fix the moisture source. Keep a copy of everything you send, and note the date.
If your landlord does not respond, send a polite follow-up and keep a record of both messages. If the mold is large, spreading, or making anyone ill, and the landlord still does not act, your local housing authority or tenants’ advice service can explain your rights in your area. Do not withhold rent or break a lease over mold without advice — the rules vary by location.
6. How to Prevent Mold Coming Back
Cleaning mold without fixing the moisture is like mopping a floor under a leaking tap. Prevention is mostly about air and water.
Ventilate every day. Open windows for a few minutes, even in winter, and use extractor fans in the bathroom and kitchen. If your apartment has no extractor fan, open a window while you shower or cook. Our guide on how to vent air in an apartment explains how to get airflow without losing all your heat.
Keep humidity below 60%. A cheap hygrometer tells you the number. If humidity is regularly above 60%, a dehumidifier helps — especially in a bathroom or basement apartment. Dry laundry outside or in a ventilated room, not draped over radiators in a closed bedroom.
Dry wet areas quickly. Wipe down shower walls, dry the bathroom floor, and mop up spills and leaks within a day. Mold can start growing on a damp surface within 24 to 48 hours.
Fix small problems fast. Report dripping taps, leaking windows and damp patches early, and check under sinks and behind appliances every few months. A small leak caught in a week is a repair; the same leak caught in six months is a mold problem.
7. Mold, Health and When to Get Help
Most people exposed to a small amount of mold will have no serious symptoms, but mold can irritate eyes, skin, nose and throat, and it can trigger asthma and allergy symptoms. People with asthma, allergies or weakened immune systems should avoid cleaning mold themselves and should leave the apartment while large areas are being cleaned.
Get medical advice if anyone in the home develops a persistent cough, wheeze, skin rash or worsening asthma after mold appears, especially if symptoms improve when they spend time away from the apartment. Tell the clinician about the mold — it helps them assess the cause.
If your apartment is also hot, damp or hard to ventilate, read why is my apartment so hot? and how to cool down an apartment without AC — heat and poor airflow often go together, and fixing ventilation helps both problems.
FAQ: How to Get Rid of Mold in an Apartment
Is it safe to clean mold myself?
For a small patch under about 10 square feet on a hard surface, yes, if you wear gloves, an N95 mask and goggles, scrub with detergent and water, and dry the area fully. Do not clean large areas, mold inside walls, or mold after flooding yourself — tell your landlord and get a professional.
Does bleach kill mold?
Bleach is not the recommended mold cleaner, especially on porous surfaces. It can irritate your lungs and eyes, damage surfaces, and leave mold underneath. Detergent and water, thorough scrubbing and complete drying are the safer approach for small hard-surface patches.
Who is responsible for mold in a rental apartment?
It depends on the cause and your location, but generally the landlord is responsible for leaks, structural damp and building faults, while the tenant is responsible for ventilation and day-to-day cleaning. Report mold in writing as soon as you find it, with photos, so the cause can be assessed.
How do I stop mold coming back in my bathroom?
Ventilate while you shower, wipe down wet surfaces, keep humidity below 60%, and fix any leaks promptly. A bathroom that dries out between showers rarely grows mold; one that stays damp all day almost always will.
How long does it take for mold to grow?
Mold can start growing on a damp surface within 24 to 48 hours. That is why drying spills, leaks and wet bathroom surfaces quickly matters more than any cleaning product.
Final Thoughts
Mold is a moisture problem first and a cleaning problem second. Find the water, fix it, clean small patches safely with detergent and water, throw out what you cannot clean, and tell your landlord in writing. Then keep the apartment ventilated and dry, and the mold has nowhere to grow. If the patch is large, keeps returning, or is inside a wall, do not try to handle it alone — that is the landlord’s job, and a professional’s.
