Happy New Year everyone,

I have a 2BR rental only about 720SF . I have had a good tenant for the past 6 years. He recently called about mold along the walls in back bedroom. When I got there I found a dark sprinkled mold in the bedroom on the baseboard and about 2 feet up the wall. There was heavy mold next to the windows/

I could tell it was not the toxic kiind a some soap and water took it right off. Now the other bedroom has a similar problem. There has never been a mold problem before.

You may want to check and see what they are setting there thermostat at and if they have changed from what they were setting at before to keep the cost down as this could be not allowing the unit to run long enough thus causing the problem.

I would also check to make sure that the windows are sealed tight and not allowing water into the wall.

Check the duct work as well to make sure that it is intact and in good condition.

Also housekeeping could be a contributor as RB said.

I keep a cheap moisture meter in my truck. Just for cases like this.

Has 2 small needle points that you stick in the material.

Compare that wall with another wall. In case maybe a leak inside the wall.

Just another simple tool to use that may indicate there is not a problem.

But I agree chances are you just had mildew.

Get a product called Mold Control. It's a concrobium product. Spray it on the wall area that you just cleaned. It will inhibit the regrowth of the mold.

Used it on a wall in my rental for the same reason as you have.

Is there a gutter over that? Could have had an overflow. Also look at his screens and storm windows. Is the top storm window really at the top? If someone puts the top window on the bottom, water can run down the window and into the window bottom.

Suggestion - If possible you need to determine if it is mold or mildew. From your post you seem to assume it is mold.

Do not use the word Mold loosely, especially around a tenant.

When I talk to tenants I don't use the word Mold unless I am absolutely sure it is Mold and not just Mildew from a leak or poor moisture control. As a LL you need to educate your self and the tenant about the difference between mildew and mold. Most people think any black or gray stain is mold, nothing could be further from the truth. Telling a tenant it is mold, and it is not, is opening up a can of worms, especially if the tenant has allergies.

Fix the problem ASAP.

First off, you cannot tell if a mold is toxic simply by looking at it, it must be tested to determine this. You can't tell by color either.

Second, I agree with 6x6 that you should look at the windows carefully to see if there is a leak or flashing issue. Also, put a humidistat in the room and take daily readings for a week. Anything over about 55% is too high.

How old is the house? Does it have insulation in the walls? Is there a vapor barrier under the siding? Is it on the side of the house that faces the sun?

when a resident says mold I issue a notice to vacate - it is a clause in my lease that court has upheld

Regardless if it is toxic - nobody should want to live in that environment - thats what I told the court

I dont care if it is great tenant that want to stay - they vacate immediately

Thanks for all the great responses. This home is an older frame with siding. windows are aluminum. NO insulation in walls I will be adding a vapor barrier on the crawl space.There is no central HVAC just a gas wall heater( vent not required) and window AC for the summer. If this info helps just leave me another message.