What Does Mold Look Like? Visual Identification Guide (2026)
What does mold look like in your house? Identify black mold, green mold, white mold, and pink mold with photos. Includes a mold identification chart, health risks, and when to call a professional.
Discovering something suspicious growing in your home can be unsettling. Is it mold? Is it dangerous? This guide will help you identify common types of household mold, understand the health risks, and know when it's time to call a professional.
In This Guide
- What is Mold? — How mold grows and spreads
- Common Types — Black, green, white, and pink mold
- Mold Identification Chart — Quick-reference comparison table
- Mold vs Mildew — Key differences
- Where Mold Grows — High-risk and hidden locations
- Health Risks — Symptoms and who's at risk
- When to Call a Pro — Professional assessment guide
What is Mold?
Mold is a type of fungus that exists naturally everywhere in our environment. It plays a vital role outdoors by breaking down dead organic matter like fallen leaves and dead trees. However, when mold starts growing inside your home, it becomes a problem.
How Mold Spreads
Mold reproduces by releasing microscopic spores into the air. These spores are invisible to the naked eye and can travel through the air, landing on surfaces throughout your home. When spores land in an area with the right conditions, they begin to grow.
What Mold Needs to Grow
For mold to establish itself in your home, it needs:
- Moisture - The most critical factor; can come from leaks, humidity, condensation, or flooding
- Food source - Any organic material including wood, paper, fabric, drywall, or even dust
- Warm temperatures - Most household molds thrive between 60-80°F (15-27°C)
- Stagnant air - Poor ventilation allows moisture to accumulate
Understanding these requirements is key to preventing mold growth in your home.
Common Types of Household Mold
Not all molds are the same. Here's how to identify the most common types you might encounter:
Black Mold (Stachybotrys chartarum)
Often called "toxic black mold," Stachybotrys chartarum is one of the most concerning types of indoor mold.
Warning: Black mold can cause serious health effects. If you suspect black mold, do not disturb it and contact a professional for mold testing immediately.
Appearance:
- Dark greenish-black color
- Slimy or wet texture when actively growing
- May appear powdery when dry
- Often has a distinct musty, earthy odor
Where it grows:
- Areas with chronic water damage
- Drywall that has been wet for extended periods
- Ceiling tiles in water-damaged areas
- Behind wallpaper
- Around persistent leaks
Key characteristic: Requires consistently wet conditions (at least 72 hours of moisture) to establish itself.
Green Mold (Aspergillus and Penicillium)
"Green mold" is a common term that typically refers to Aspergillus or Penicillium species, which are among the most common indoor molds.
Appearance:
- Ranges from light green to dark olive green
- Can appear blue-green or yellow-green
- Usually has a powdery or fuzzy texture
- May have white edges where actively growing
Where it grows:
- On food items (bread, fruits, vegetables)
- Air conditioning systems and ductwork — learn more in our complete mold removal guide
- Walls and insulation
- Fabrics and carpets
- Wallpaper and painted surfaces
Key characteristic: These molds spread rapidly and can cover large areas quickly. While many strains are relatively harmless, some can cause allergic reactions or respiratory issues.
White Mold
White mold refers to several mold species in their early growth stages or specific types that remain white throughout their lifecycle.
Appearance:
- White or light gray color
- Powdery or fluffy texture
- Can be mistaken for efflorescence (mineral deposits) on concrete
- May have a subtle musty smell
Where it grows:
- Basement walls and floors
- Attics and crawl spaces
- Around wood framing
- On furniture
- In closets with poor ventilation
Key characteristic: Often appears first in areas with high humidity but not direct water exposure. Frequently the earliest sign of a moisture problem.
Pink Mold (Aureobasidium pullulans and Serratia marcescens)
Pink mold is commonly found in bathrooms and other wet areas. Interestingly, the pink growth in your shower may actually be bacteria (Serratia marcescens) rather than true mold.
Appearance:
- Pink, orange, or reddish color
- Slimy texture
- Often appears in circular or spot patterns
- May darken to brown or black as it ages
Where it grows:
- Bathroom tiles and grout
- Shower curtains and liners
- Around faucets and drains
- On shampoo bottles and soap dishes
- Window sills in humid rooms
Key characteristic: Very common in bathrooms due to soap residue and standing water. While usually not as dangerous as black mold, it can cause respiratory issues and infections, especially in immunocompromised individuals.
Mold Identification Chart
Use this quick-reference table to help identify what type of mold you're seeing:
| Mold Type | Color | Texture | Common Locations | Risk Level |
|---|---|---|---|---|
| Black mold (Stachybotrys) | Dark greenish-black | Slimy when wet, powdery when dry | Chronically wet drywall, ceiling tiles, behind wallpaper | High — seek professional help |
| Green mold (Aspergillus/Penicillium) | Light to dark green, blue-green | Powdery or fuzzy | Food, HVAC systems, walls, carpets | Moderate — can cause allergic reactions |
| White mold | White to light gray | Powdery or fluffy | Basements, attics, crawl spaces, wood framing | Moderate — early sign of moisture problems |
| Pink mold (Aureobasidium/Serratia) | Pink, orange, reddish | Slimy | Bathroom tiles, grout, shower curtains, drains | Low to moderate — infections in immunocompromised |
Note: Color alone is not a reliable way to identify mold species. Many molds change color as they grow, and laboratory testing is the only way to confirm the exact species. When in doubt, get a professional mold assessment.
Mold vs Mildew: How to Tell the Difference
Mold and mildew are both fungi, but they differ in appearance, growth patterns, and severity:
| Mold | Mildew | |
|---|---|---|
| Appearance | Fuzzy, raised, often dark-colored | Flat, powdery or downy |
| Color | Black, green, red, blue — many colors | Usually white, gray, or yellowish |
| Texture | Penetrates surfaces | Sits on top of surfaces |
| Growth pattern | Irregular patches, can grow behind walls | Grows on surface in flat patterns |
| Common locations | Drywall, wood, insulation, HVAC | Shower tiles, window sills, fabric |
| Health impact | Can cause serious respiratory issues | Milder symptoms, primarily allergic |
| Removal | Often requires professional remediation | Usually cleaned with household products |
The key difference: Mildew sits on surfaces and is relatively easy to clean. Mold penetrates materials and often requires removing the affected material entirely. If growth is raised, fuzzy, or dark-colored, treat it as mold and take appropriate precautions.
Where Mold Commonly Grows
Understanding common mold locations helps you identify problems early:
High-Risk Areas
- Bathrooms - Near showers, tubs, toilets, and under sinks — Bathroom mold guide →
- Kitchens - Under sinks, around refrigerators, and near dishwashers
- Basements - On walls, floors, around foundation cracks — Basement mold guide →
- Attics - Near roof leaks, around vents, on insulation — Attic mold guide →
- Laundry rooms - Behind washers, around dryer vents
- Crawl spaces - On floor joists, vapor barriers, and supports — Crawl space mold guide →
Hidden Locations
Mold often grows where you can't easily see it:
- Behind drywall and wallpaper
- Inside HVAC ducts and systems
- Under carpeting and padding
- Behind cabinets and furniture
- Inside wall cavities around plumbing
- Beneath flooring materials
Signs of Hidden Mold
Even if you can't see mold, these signs may indicate its presence:
- Persistent musty or earthy odors
- Visible water stains on walls or ceilings
- Peeling or bubbling paint or wallpaper
- Warped or buckled flooring
- Chronic allergy symptoms that improve when away from home
Health Risks Associated with Mold
Mold affects people differently based on their sensitivity, exposure level, and the type of mold present.
Common Symptoms of Mold Exposure
Most people experience mild symptoms including:
- Nasal congestion and runny nose
- Sneezing
- Eye irritation (redness, itching, watering)
- Skin rashes or irritation
- Throat irritation
- Coughing
- Headaches
More Serious Reactions
Some individuals may experience severe reactions:
- Difficulty breathing or shortness of breath
- Fever
- Chronic fatigue
- Memory problems or difficulty concentrating
- Persistent sinus infections
Warning for High-Risk Individuals: People with compromised immune systems, chronic respiratory conditions, allergies, or asthma are at significantly higher risk from mold exposure. If you fall into these categories, take extra precautions and seek professional help for any mold issues.
When to Call a Professional
While small mold problems (under 10 square feet) can sometimes be addressed with DIY methods, certain situations require professional help. Not sure if you can handle it yourself? DIY vs professional removal →
Call a Professional Immediately If:
- The affected area exceeds 10 square feet - Larger infestations require professional containment and removal
- You suspect black mold - The health risks are too significant for DIY remediation
- Mold is in your HVAC system - Can spread spores throughout your entire home
- You've had sewage backup or contaminated water - Creates additional health hazards
- The mold keeps returning - Indicates an unresolved moisture problem
- You or family members have health symptoms - Especially respiratory issues
- You can smell mold but can't find it - Hidden mold requires professional detection
Important: When in doubt, err on the side of caution. A professional mold assessment is relatively affordable and can prevent costly health and property issues.
What to Expect from a Professional Assessment
A certified mold assessor will:
- Conduct a thorough visual inspection
- Use moisture meters to detect hidden water issues
- Collect air and/or surface samples if needed
- Identify the moisture source causing the problem
- Provide a detailed report with remediation recommendations
Choosing the Right Professional
Look for professionals who:
- Hold state licensing (required in many states for mold assessors)
- Carry appropriate insurance coverage
- Have verifiable certifications from recognized organizations
- Provide detailed written assessments
- Do not have conflicts of interest — an assessor should not also do remediation (learn why)
Next Steps
If you've identified or suspect mold in your home, take action:
- Document what you see - Take photos and note the size and location
- Address the moisture source - Mold cannot survive without moisture
- Avoid disturbing the mold - This can release more spores into the air
- Assess the scope - Is it under or over 10 square feet?
- Decide on approach - DIY for small areas, professional for larger issues or black mold
Find a Verified Mold Professional
Don't trust your home and health to just anyone. Find a verified mold assessor in your area who has been vetted for proper licensing, insurance, and professional reputation.
📚 This guide is part of our Complete Mold Remediation Guide—your comprehensive resource for understanding, preventing, and removing mold.
Frequently Asked Questions
What does mold look like on walls?
How can you tell the difference between mold and mildew?
Is all black mold toxic?
Can mold be hidden behind walls?
What does mold smell like?
How quickly should you address mold in your home?
This guide is for educational purposes only. Always consult with certified professionals for specific mold situations in your home. If you experience health symptoms, please consult a healthcare provider.