Mold and Moisture in a Rental Home

Everyday habits that keep a home dry

From the guide’s own habits. Tick each one as you go. Your ticks stay on this device. These are examples; your home may need others.

• Run the bathroom fan during showers and for 20 to 30 minutes after.
• Use the range hood while cooking, and keep lids on pots.
• Wipe window condensation.
• Keep the shower curtain inside the tub.
• Keep indoor humidity between 30 and 50 percent, and below 60 percent at most. An inexpensive humidity gauge makes this easy to check.
• Keep vents and return grilles clear, and leave interior doors open when you can.
• Do a dry paper towel check under every sink once a month.
• Let your owner know in writing, with a photo, whenever you notice a leak, stain or musty smell.

All done. Your home has a steady plan to stay dry.

If you find a leak

1. Keep everyone away from water near electricity first.
2. Stop the water at the nearest valve or the main shutoff.
3. Mop and towel up water, and run fans and a dehumidifier.
4. Move belongings off wet floors and out of wet cabinets.
5. Photograph everything and report it urgently, by phone and in writing.
6. Soaked carpet and pad, wet drywall, wet insulation and anything still damp after 48 hours usually need professional drying. Water from toilets, sewers or floods needs professional cleanup.

If water is coming through a ceiling or a ceiling is sagging, stay out from under it, turn off power to that area only from a dry spot and call right away.

Cleaning a small mold spot safely

From the guide’s own steps for a small spot on a hard surface. Tick each one as you go. Your ticks stay on this device. These are examples; your home may need others.

• Fix or report the moisture source first.
• Keep children, pregnant people, anyone with asthma and pets out of the room.
• Wear rubber gloves, goggles without vent holes and, ideally, an N95 mask.
• Open a window or run a fan blowing outward if possible.
• Scrub with detergent and water, then dry the area completely.
• Bag used rags and throw them away.

All done. Keep an eye on the spot, and report it if it comes back.

What not to clean yourself

• Areas larger than about 10 square feet.
• Mold in heating and cooling ducts.
• Mold after sewage or floodwater.
• Mold on porous materials like ceiling tiles, insulation or carpet, which often need replacing.
• Anything high enough to need a ladder.

Bleach isn’t required for most mold cleanup. If you choose to use it, follow the label, ventilate well and never mix it with ammonia or other cleaners. If anyone is exposed, Poison Control can help at 1 800 222 1222.

A few things to avoid

• Please don’t point a fan at mold.
• Please don’t paint over mold. It grows back through the paint. Clean, dry and fix the moisture first.
• Please don’t mix bleach with other cleaners.

When you see mold, ask first: where is the water coming from?

The moisture walk at move in and move out

From the guide’s move in and move out check. Tick each one as you go. Your ticks stay on this device. These are examples; your home may need others.

• Check under sinks, around tubs and toilets, closets on outside walls and around windows.
• Run the tissue test on each bath fan.
• Record the humidity in a few rooms.
• Photograph and date what you find, and send the list early.
• Repeat the same walk at move out.
• Report anything new honestly and promptly, including stains found behind furniture while packing.

All done. Your moisture walk is on record.

Do the move in moisture walk before your furniture arrives, when walls and closets are easy to see. Bunklow Walk makes the move in report easy. See Bunklow Walk.

Before move in

From the guide’s list for owners. Tick each one as you go. Your ticks stay on this device. These are examples; your home may need others.

• Clean the gutters.
• Check every vent fan.
• Recaulk tubs and sinks.
• Fix and dry any leaks.
• Walk these areas together with your tenant at move in.

All done. The home starts out dry.

Raising a concern without blame

Mold isn’t a cleaning failure or a sign that someone is careless. It’s what happens when water stays where it shouldn’t. Here is the guide’s own wording, word for word:

Raising a moisture concern. “Hi, I’ve noticed some mold spots in the bedroom corner that keep coming back, even after cleaning. I’m running the fan and keeping humidity down, so I think there may be a moisture source we can’t see. Could we look at it together? Thank you.”

Reassuring a worried resident. “Thank you for telling me about the mold. You did exactly the right thing. Mold almost always comes from a moisture problem in the building, and we’ll find it and fix it together.”

Guides that go well with this one

• Humidifiers and Dehumidifiers
• Indoor Air Quality
• Windows and Condensation
• Basements and Crawl Spaces
• Leaky Faucets and Fixtures

Helpful resources

U.S. Environmental Protection Agency: Mold. Who handles what is shaped by the lease and by the rules where the home is. Owners usually fix leaks and building problems, and residents control everyday moisture and report promptly. Every state handles this a little differently, so we’d gently encourage a quick look at the rules where your home is. A local landlord or tenant association or an attorney in your area can help.