If you rent, you usually cannot fix the leak, replace the drywall or change the ventilation that causes mold. What you can do is document it well, report it the right way and keep the moisture down while it gets fixed.
Is it mold?
Mold is usually fuzzy or slimy, grows in spots that spread, and smells musty. Water stains are flat and do not grow. You do not need to know the species: CDC and EPA advise that any mold growing indoors should be removed, and there are no federal limits to compare a test against. "Black mold" is not a separate danger category; the color does not tell you how harmful it is.
Document it before you report it
- Photos with dates, close up and wide, and again every week or two to show it spreading.
- The cause if you can see it: a leak, condensation on windows, a bathroom with no working fan.
- Humidity readings. A cheap hygrometer or air quality monitor that shows humidity above 60% for days is evidence of a moisture problem, not just poor housekeeping.
- Any damage to your belongings, and any doctor visits.
Report it in writing
Tell the landlord or property manager by email or through the tenant portal, not only by phone, so there is a dated record. Describe where, how big, the likely moisture source, and ask for the repair and a date. Keep copies of every reply. In most states, landlords must keep a rental fit to live in, and some states and cities name mold specifically; California, for example, lists visible mold as a substandard housing condition.
If the landlord says it is not mold, or does nothing
- A professional mold assessment gives you a written report from a third party, which carries more weight than a DIY kit. Only a few places license mold assessors, among them Texas, Florida, New York, Louisiana and Washington DC; see your state on our air quality by state pages.
- Local code enforcement or the health department can inspect for housing code violations in many cities.
- In HUD-assisted housing, the federal inspection standards cover mold-like growth, and you can ask the housing authority for an inspection.
- Tenant rights groups and legal aid know your local rules. Get their advice before withholding rent or breaking a lease; doing either the wrong way can leave you owing money.
What you can do meanwhile
- Keep humidity at 30 to 50%: run bathroom fans during and after showers, use the kitchen fan, and run a dehumidifier in damp rooms.
- Wipe condensation off windows and keep furniture a few inches off damp outside walls.
- EPA's guidance is that a small patch under about 10 square feet can be cleaned with detergent and water. Ask the landlord first, since cleaning does not fix the moisture behind it, and photograph it before you clean.
- Do not paint over mold. It grows back through the paint and hides the evidence.
Health
Mold can trigger stuffy nose, wheezing, itchy eyes and asthma attacks, and people with asthma, allergies or weakened immune systems are more affected. If you have symptoms, see a doctor and tell them about the mold; a note from your doctor also strengthens a repair request.