Mold inspection in Ann Arbor
Almost every other page on this site depends on this one. With no state license to check and no legal exposure limit to measure against, the survey report is the only evidence you have that somebody competent understood your building.
The awkward part
There is nothing to measure against
Most inspections in most trades end in a number compared to a limit. Mold has no such limit. Washtenaw County states the position plainly: in most cases testing or sampling for mold is not necessary, because there are no established safe levels or regulatory standards for mold. There is no federal exposure limit, no state one, and no threshold above which a result means anything definite.
Which puts a lab result in an odd position. A spore count of some number per cubic meter cannot be compared to a legal maximum, because none exists. It can only be compared to another sample, usually one taken outdoors on the same day, and interpreted by somebody with the training to say what the comparison means. That is a real discipline, and it is also not what most people are sold when a company offers a free mold test.
In most cases, testing or sampling for mold is not necessary. There are no established safe levels or regulatory standards for mold.Washtenaw County Health Department · Mold testing
The city's rental office reaches the same place from a different direction. Its guidance to tenants says its office cannot test nor recommend anyone to test for mold or lead, and refers environmental health questions to the county on 734-222-3800. Two public offices, both declining to route people toward testing.
When it does earn its cost
Five situations where sampling is worth paying for
The county does not say testing is never appropriate. It lists the specific circumstances where it is, and the list is short enough to check yourself before agreeing to anything.
- Someone in the household has symptoms that appear related to mold exposure, and a doctor is involved in the question.
- There is a musty odor with nothing visible. Here sampling is doing real work, helping locate something you cannot see.
- You suspect hidden growth after water damage, typically behind a wall or under a floor that has already been wet.
- You need to confirm a remediation actually worked, which is the one case where a before-and-after comparison has a clear meaning.
- You need documentation for a sale or a legal matter, where the point of the report is evidence rather than diagnosis.
Outside those five, the county's guidance is to assume a problem exists and go looking for the moisture. If a company's first proposal is a paid air sample and your situation is not on that list, ask which of the five it thinks applies.
Where sampling is warranted, the county is specific about who should do it: professionals with experience in designing sampling protocols and interpreting results, with analysis following methods recommended by the American Industrial Hygiene Association or the American Conference of Governmental Industrial Hygienists. That is a fair thing to ask about before the swab comes out.
What the visit is for
Looking for water, not for mold
If the mold is visible, its location is not the discovery. The discovery is why that particular surface is wet, and a survey that does not answer that has not finished. Washtenaw County puts moisture first in its own cleanup guidance: the most important step in solving a mold problem is identifying and correcting the moisture sources that allowed it to grow.
What a competent survey covers
- The whole moisture story of the building, not the room you called about. Roof, gutters and where they discharge, grading against the foundation, the sump, the crawl space, and where every exhaust fan in the house actually terminates.
- Readings rather than impressions. Relative humidity in the affected space, surface temperature where condensation is suspected, and moisture content in the materials themselves. The target range to work back to is 30% to 60% relative humidity.
- Whether the problem is seasonal, which is the single most useful question in a Michigan basement. Worse in July points at condensation; worse after heavy rain points at water arriving through the wall; unchanged all year points at a leak.
- The extent, measured. Square footage decides the method and the price, and the thresholds are public: about 10 square feet, and 100.
- Whether the air handling system is implicated, because if it is, the instruction is to stop running it before anything else happens.
What belongs in the written report
A survey you cannot hold a later quote against has not given you much. The document should name the moisture source and the evidence for it, state the affected area in square feet, list which materials are coming out and which are being cleaned, and separate the moisture repair from the mold work as two distinct pieces with their own prices. Photographs throughout, and readings with the locations they were taken at.
The separation matters more than it looks. Remediation without the moisture repair is temporary by definition, and quoting them as one undifferentiated figure makes it impossible to tell whether the moisture repair is in there at all.
Straight answers
Questions about the survey itself
Should a survey be free?
A free survey is paid for by the work it recommends, which is a structural reason to expect it to recommend work. That does not make every free assessment dishonest, and plenty of good companies offer one. But a paid survey from somebody who is not going to do the remediation is the version with no conflict in it, and on a large or contested job (a purchase, an insurance claim, a dispute with a landlord) it is usually worth the money.
Can I just do this myself?
For a small patch, largely yes, and the county publishes the method instead of gatekeeping it: under about 10 square feet, with gloves, goggles, an N-95 and the moldy material bagged before it is carried through the house.
What is harder to do yourself is the diagnosis. Distinguishing a wall that is wet from outside from one that is condensing is a judgment made from several readings, and getting it wrong means either digging up a garden that was fine or running a dehumidifier against a leak.
The seller's disclosure says no known mold. Is that worth anything?
It is a statement about knowledge, not about condition, and in a city where 45.5% of housing units are owner-occupied a good number of sellers are landlords who have not been in the basement lately. If a house has a below-grade finished room, the useful questions are what is behind the paneling, where the sump discharges, and whether the downspouts run away from the foundation. None of those need a lab.
What if the survey does not find anything?
That is a legitimate outcome and you should be told it plainly. A musty smell in a basement that turns out to be a damp concrete floor in August, with humidity that a dehumidifier will hold in range, is a real answer even though it comes with no invoice for demolition.
The version to be wary of is the survey that never returns a negative — if every visit a company makes discovers work, the visit is not a survey, it is the first stage of a sale.
How long does a survey take?
An hour to two for a typical house, longer if there is a crawl space or the moisture source is not obvious. If somebody is in and out in fifteen minutes with a price, they have measured nothing, and the number they wrote down is based on the same information you already had.
Start with a survey, not a sales visit
Ask for a survey
Tell us what prompted it: a smell, a stain, a purchase, a leak you already know about, or an inspector's write-up. What started it changes what the visit should be looking for, and it is worth settling before anyone books a date.
Related work we arrange
What a survey usually leads to
Basement and crawl space mold
Where most Ann Arbor mold lives. A below-grade wall can be wet from outside, wet from condensation, or wet from a leak, and the three want completely different repairs.
Attic mold and roof ventilation
Usually a ventilation fault rather than a roof leak. A bath fan discharging into the attic puts warm wet air against a cold roof deck every night of a Michigan winter.
Water damage drying and material removal
The 48-hour window the EPA sets for drying wet building materials, and which porous materials have to come out rather than be dried in place.
Rental property mold and certificates of compliance
Ann Arbor inspects every rental unit every 30 months. Passing that inspection and fixing the moisture behind it are two different jobs, and only one of them holds until the next one.