Mold Testing – How to test for mold in house

The problem of hidden and invisible mold

Mold that has grown into colonies is easily visible and is detected on time. However, there can be mold present in your house that is totally invisible and resides in air and leaves no visible traces anywhere. And still it would affect your health.

Mold Testing

Mold testing a process of analyzing the air quality in a particular area of your house, like a bedroom or bathroom. Specific chemical tests are able to test and detect mold spores that are present and thrive in just the air around without giving any signs of presence other than health problems to the occupants.

The test can tell if there is hidden mold in the place, the level of air quality and also identify the species of molds present.

Professional Mold Testing

Mold testing can be done by a proper mold testing agency or service provider. They will collect samples and send it for analysis to labs and get accurate reports on the mold samples. Hiring professionals gets you highly detailed and accurate reporting on the mold.

mold testing
Mold Testing

To find a suitable mold testing service in your locality search on google or some local classifieds site.

DIY Mold testing kits

The other way of testing for mold is doing it yourself with mold testing kits that are easily available in the market. You can find a good do-it-yourself mold testing kits on

This particular video shows how a mold testing kit can help you discover invisible mold that resides in the atmosphere without you having any knowledge of it.

Mold testing kits are a less expensive way of testing for presence of mold in your house, but with limitations. These mold kits can be used to detect active mold spores in the atmosphere or on a surface.

However they cannot give you detailed information about the species of the mold, or whether they are toxic or not. For a detailed analysis you better opt for a professional mold testing provider.

Types of Mold Tests

The three main types of mold tests, depending on how the mold samples are collected –

  • Air testing
  • Surface testing
  • Bulk testing

Air Testing for Mold

Air test checks for mold spores present in the air. The samples are collected from a particular room at a time and then the samples undergo examination. These samples under examination reveal if mold is present in the air and in what quantity.

This test helps to detect mold, even if there are no visible signs or symptoms. The test reveals the quality of the air that all the occupants of the house are breathing.

Surface testing for Mold

Surface testing involves collecting samples from somekind of a surface where there might be some signs of mold growing. For example a wooden surface. Samples are collected using cotton swab, tape lifting or other methods. Later on, its send for analysis to the laboratory.

Surface test can detect, if the moldy growth is actually mold or just soot or dirt. If its detected as mold, then you know its time to clean it.

Bulk Testing for Mold

Bulk testing is a more intensive way of carrying out the tests for mold. In the process, actual objects or pieces of affected material are collected from the home and take to the laboratory for examination under the microscope.

Culture Test

In Culture test, the mold sample is kept in a special environment where it can grow into large colonies. Then the colony can be examined to identify the species of the mold.

This method is used in many diy mold testing kits where in, after collecting the sample you have to keep it in a special chemical apparatus where it will grow into colonies in a few day. The culture test works only if there are alive mold spores in the sample that are capable of growing.

However, even dead mold particular can cause health issues. So even if the culture tests show negative signs of mold in the sample, you can go for other tests that can detect even the dead mold spores.

When do you need to test for mold

Like mentioned earlier, the main reason behind mold testing is to detect mold that is invisible or difficult to detect by human eyes.

However, you may want to go for mold test due to any or all of the following reasons –

  • You notice signs of mold and want to do a thorough inspection
  • Identify the mold species and get information of related health issues
  • Find the source and root cause of the mold growth
  • Test the quality of air indoors by measuring the mold spore density
  • To check if mold has been completely removed after treatment

Presence of Mold signs and symptoms

The foremost reason to go for mold testing and inspection is the presence of mold signs in your house. These can be visible mold growing in some part of the house or health problems being faced by some or all members of the house.

If you notice musty smell in any corner of the house, it is a strong indication of mold growing somewhere.

If any member of the house is suffering allergic symptoms, there could be mold present in the air or some surface that is often touched or comes in human contact. Mold in air will cause breathing or respiratory problems like irritation, sneezing etc. Whereas mold on surfaces will cause skin problems.

For more information on the health problems and symptoms caused by mold, check this post –

What are the health symptoms caused by black Mold

Identifying Mold Species

Another important reason to go for mold testing is to identify the mold species. This might sound insignificant. However there are scenarios where the mold the highly toxic and spreads rapidly due to climatic and environmental conditions. In such cases, the residents of the place need to exercise greater caution to be safer.

Some of toxic mold species are Stachybotrys (often called toxic black mold) and Aspergillus.

If there is mold infection somewhere in your house or even outdoors, which are unable to eliminate permanently and you are suffering toxic symptoms due to it, then its extremely necessary to get the mold tested. Such an examination can be done only by professional testing labs.

Finding the root cause of Mold

Sometimes, it could be difficult to identify the exact location where mold is originating in your house. You entire house might feel free of water and moisture problems and yet there might be mold coming in from somewhere.

The test can identify the exact location where the mold is originating from. For example damaged walls that are absorbing moisture from outdoors or wooden structure absorbing moisture from soil. Once you are able to identify the exact place the mold is coming from, treatment becomes easier.

Testing indoor air quality

Mold testing also reveals the level of air quality in places where mold spores appear even after repeated treatments.

Assessing the air quality becomes even more important if there are kids or pets in the house. They are more susceptible to health problems and symptoms and need more care.

Sometimes, there are no visible signs of mold growing anywhere in the house and still the members suffer breathing problems. This can be due to mold spores that are present in the air that might have come from outdoors. In such a situation, its better to get the air quality level checked and proper mold test done.

If the test reveals that there indeed are mold spores present in the air, you can be sure of what treatment needs to be done next.

Mold testing after Mold removal

If there has been a lengthy mold treatment process going on in your house, its a very good idea to do a mold test after the mold removal is done. This is useful to ensure that the mold removal process was successful and that mold was actually removed completely without any left over traces.

All the places affected by mold earlier should be thoroughly tested. Samples should be collected from air and surfaces. If the test shows residual presence of mold anywhere, then you need to carry out the removal process and cleaning again.

Once the tests show that the mold spores have been completely eliminated and that the air quality level is in a safe range, you can be sure that the job is done quite well.


That was some very basic information about mold testing. To learn more about the process you should contact some local mold testing laboratory.

Mold testing is becomes necessary in cases where its difficult to detect the mold by mere visual inspection. It happens when mold spores either originate from deep hidden places or are carried into the house from outdoors by airflow.

If the mold is visible, its easily detected and all you need to do is to prepare for the cleaning and removal process. Then you can just do the usual cleaning and skip the testing unless it seems necessary later on.

References and Resource – More information about mold testing and sampling at EPA – Information on Mold Testing at Minnesota Department of Health

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