How should I clean mold and mildew at home?
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Fix the water problem first, then scrub the mold off hard surfaces with detergent and water and dry the area completely. That is EPA's household advice: "The key to mold control is moisture control," and "Scrub mold off hard surfaces with detergent and water, and dry completely" [1]. EPA says chlorine bleach "is not recommended as a routine practice during mold cleanup" [1]. Porous materials such as ceiling tiles and carpet may have to be thrown away, and growth larger than about 10 square feet calls for EPA's larger-scale guidance or a professional [1]. This page sorts what you see into what to do, and explains what a "removes mold stains" label does and does not promise.
What you see, what it means, what to do
| What you see | What it likely means | What to do |
|---|---|---|
| Gray or black specks on shower grout, caulk or the tile above the tub | Surface growth fed by daily moisture | Scrub with detergent and water, dry, and improve ventilation after showers [1] |
| Dark spots on a window sill or the inside of a window frame in cold weather | Condensation | Clean and dry; reduce indoor humidity or condensation so it does not return [1] |
| A musty smell with no visible growth | Hidden moisture, behind a wall, under a floor or in an HVAC system | Find the water source. If you suspect the HVAC system, do not run it [1] |
| Mold on drywall, ceiling tile or carpet | Growth into a porous material | It may have to be removed and replaced [1] |
| Growth covering more than about 10 square feet | Too large for a routine household cleanup | Use EPA's mold remediation guidance or hire a contractor with mold cleanup experience [1] |
| Mold after sewage backup or flooding with contaminated water | Contamination beyond mold | Call a professional experienced with water-damaged buildings [1] |
| Stains left after scrubbing | Pigment in grout or caulk | Stain removal is a cosmetic step; replacing old caulk may be simpler |
Cleaning a small area yourself
EPA says you can usually handle a small patch yourself [1]. A practical sequence:
- Find and stop the moisture. A leak, a drip, poor bathroom ventilation or condensation. EPA's point is that if the water problem is not fixed, the mold "will likely return" [1].
- Protect yourself. EPA suggests considering an N-95 respirator, wearing gloves so you do not touch mold with bare hands, and wearing goggles without ventilation holes so spores stay out of your eyes [1]. If you have health concerns, EPA says to consult a health professional before you start [1]. More on choosing protection is on do I need gloves, eye protection or open windows?.
- Scrub with detergent and water. A stiff brush on grout, a cloth on smooth surfaces. The detergent and friction remove the growth [1].
- Dry completely. Fans, an open window, a towel. EPA's instruction ends with drying for a reason: moisture is what mold needs [1].
- Bag porous waste. Moldy rags, sponges and small porous items go in a sealed bag.
- Watch the spot. If growth comes back within weeks, the moisture source is still there.
EPA is frank about the goal: "It is impossible to get rid of all mold and mold spores indoors," because spores are always in the air and dust [1]. Controlling moisture is what keeps them from growing.
When bleach is and is not called for
EPA's mold booklet says using a biocide such as chlorine bleach "is not recommended as a routine practice during mold cleanup" [1]. There may be exceptions, such as when people with weakened immune systems are present, and EPA notes that dead mold must still be removed because it can still cause allergic reactions [1]. In other words, killing mold is not the same as removing it, and removal with detergent and scrubbing is the main job.
If you do use bleach:
- Never combine it with ammonia. EPA: "Never mix chlorine bleach solution with other cleaning solutions or detergents that contain ammonia." [1] The reaction releases toxic chloramine vapors; see bleach and ammonia. Bleach must not meet acids such as vinegar either.
- Follow your bleach label. If your bleach is an EPA-registered product with mold or mildew directions, use them. CDC's household bleach dilution is a disinfecting figure for surfaces, with its own conditions, on making a bleach disinfecting solution; no separate mold or mildew bleach ratio is given here.
- Ventilate and keep the area clear of children and pets until it is dry.
- Expect damage. Bleach can discolor grout, fabric and some finishes. Which surfaces tolerate which cleaners is on which cleaners are safe on granite, wood, grout and stainless steel?.
Porous materials
EPA says "absorbent or porous materials, such as ceiling tiles and carpet, may have to be thrown away if they become moldy" [1]. Mold grows into the material, where scrubbing cannot reach it. Hard, nonporous surfaces such as glazed tile, glass, sealed countertops and metal can be cleaned. Drywall, ceiling tile, carpet, upholstery and unsealed wood that are moldy usually cannot be cleaned to the point of being sound again, which is why EPA's advice turns from cleaning to removal there.
What "removes mold stains" means on a label
Label wording around mold follows federal pesticide law, and the line is between cleaning and killing.
- Cleaning claims. EPA lists "cleans or removes stains from algae, mold, mildew or other non-public health organisms" as a claim that does not, by itself, make a product a pesticide [2]. A cleaner that says "removes mildew stains" is telling you it lifts discoloration. It is not claiming to kill anything.
- Killing claims. A label that says it kills mold, prevents mold growth or controls mildew is making a pesticidal claim and must be an EPA-registered product [2].
- Minimum risk 25(b) products. EPA allows them a claim to control "mold stain" with the right qualifications, but says "neither 'mold remediation' nor 'mold control' can be used as a claim on a minimum risk product" [3]. 25(b) does not cover germ claims of any kind [3].
For you as a buyer, this explains why many bathroom cleaners say "removes mold and mildew stains" in careful words. For you as a maker, it is the wording to stay within; see how do I describe my cleaner without making a germ claim?.
When to call a professional
EPA's thresholds and triggers [1]:
- Mold covers more than about 10 square feet.
- The water damage came from sewage or other contaminated water.
- You know or suspect mold in the heating, ventilation and air conditioning system.
- You have health concerns about doing the cleanup yourself.
For a contractor, EPA says to choose one with experience in mold cleanup [1].
Keeping shower mold from coming back
Most household mold is in the bathroom, where it comes back as long as the room stays damp. Published cleaner recipes for tubs, tile and soap scum, and the habits that prevent buildup, are on what homemade cleaner works on soap scum and hard-water spots?.
References
- U.S. EPA, A Brief Guide to Mold, Moisture, and Your Home, EPA 402-K-02-003, reprinted September 2012. https://www.epa.gov/sites/production/files/2016-10/documents/moldguide12.pdf
- U.S. EPA, Determining If a Cleaning Product Is a Pesticide Under FIFRA, last updated July 6, 2026. https://www.epa.gov/pesticide-registration/determining-if-cleaning-product-pesticide-under-fifra
- U.S. EPA, Conditions for Minimum Risk Pesticides, last updated August 31, 2026. https://www.epa.gov/node/64449
