Are you ready to have you home inspected for mold and water damage? 

If so, you are probably thinking of hiring an Indoor Environmental Professional (I.E.P.) – a smart move, as this person plays a key role in determining what might be going on in your home or building. 

However, finding the right I.E.P. to inspect your home can be an overwhelming process because “I.E.P.” is a general term used to describe someone who performs indoor environmental inspections and assessments of a building. The requirements, qualifications, and skill sets vary greatly among I.E.P.s.  

You cannot assume that because a person is an I.E.P. that they are bound by certain requirements, standards, laws, or operating procedures. 

Further, if an I.E.P. doesn’t do their job well, your family could be wasting valuable time and money while also putting the health of you and your loved ones at further risk. This is why you must thoroughly vet anyone you hire. 

To make this process a little less overwhelming, we have provided some sample questions that can assist you when hiring an I.E.P.  

Questions about the process:

  • What does a typical mold inspection look like? Does your inspection include the entire home (including the exterior areas as well as attics, basements, crawlspaces, and HVAC)? Is there anywhere you won’t look during your inspection? How long does it last?
    • A good I.E.P. understands that mold is often hidden. Just because you may not see or smell mold doesn’t mean it’s not there! Further, what is visible, may just be the tip of the iceberg and can be the first clue to a much bigger problem that is hidden underneath surfaces, walls, and flooring. 

    • A good inspection includes the entire home, top to bottom, including hard to reach places like attics, crawlspaces, basements, HVAC systems, and ductwork. It should also include an inspection around the exterior of the property to look for drainage, grading, and other issues that may impact the home. 
      Your I.E.P. should use a variety of tools and a variety of tests. Tests should include source samples (areas of actual or suspected microbial growth) and progressive samples (areas that may be impacted by cross contamination from source areas). 
      The I.E.P. should also factor in the history of the home and the health symptoms of the people in it. This is usually a multi-hour investigation.
      To learn more about the role of an I.E.P. and what a good inspection looks like, be sure check out our interviews with Indoor Environmental Professional, Brian Karr, here and here.

  • How does the history of the home factor into your inspection?
    • The history of the home, when known, should play a key part in an inspection. Historical water damage from things like burst pipes, floods, leaks, overflowed tubs, toilets, and washing machines are important clues. Water that is trapped behind walls for longer than 24-48 hours can lead to mold growth. Do not hire an I.E.P. who dismisses the signs of water damage simply because the area is now dry. Dormant mold growth is still a health hazard.
  • How do I prepare my home for your visit? Do I need to empty out closets or under sinks? Do I need to turn off air purifiers or keep windows closed for a certain period prior to your visit?
    • Each inspector will have their own requests in this area. Your I.E.P. may ask you to turn off any air purifiers and keep the windows closed for a few days prior to inspection. Even if your I.E.P. does not request it, it’s generally a good idea to empty out everything from under your sinks. You want your I.E.P. to be able to easily see any signs of water damage. While you usually do not need to empty out your closets, make sure your I.E.P. can clearly see the floor and walls. Consider pulling furniture away from walls and windows so your I.E.P. can easily see walls, baseboards, and areas around windows. Most I.E.P.s will not move furniture or belongings, so it is important that you make these areas as accessible as possible.

Questions related to tools and testing:

  • What tools do you use to help in your inspection?
    • Tools like moisture meters, thermal imaging cameras, hygrometers, and flashlights can assist an investigation. All tools have specific purposes and limitations. The most important tool your I.E.P. should use are their eyes. Do not rely on an I.E.P. who depends solely on tools like moisture meters or thermal cameras as these tools may miss previous water damage that has already dried.
  • What types of testing do you do? How do you conduct each of those tests?
    • There are a variety of tests that can provide valuable information about your home. It is important to remember that all tests have specific purposes and limitations and that there are no perfect tests. All testing should be targeted and strategic. If your I.E.P. suspects an area of your home is a problem, testing can confirm if that is true. The information from that test will help the I.E.P. provide an accurate assessment of what might be going on in your home.


      An I.E.P. will match the type of testing to what is found in the home. Testing methods may include air testing (close to a suspected source or in a wall cavity), dust testing, and surface sampling (i.e. swab or tape). How a test is conducted influences the accuracy of the results. Your I.E.P. should be able to explain how and why they are collecting tests in that way. Do not rely on an I.E.P. who only takes ambient air samples in the center of different rooms. Testing in this way may not arcuately reflect what is going on in the home. 
      Be sure to check out our website for our upcoming mini classes on testing options for your home.
  • How do you decided when a test is needed?
    • All testing should be done for a specific reason and to collect specific data. Testing is done to prove or disprove if mold, microbial growth, or other contamination are present in the home. An I.E.P. should be able to tell you why they are testing a specific area. An I.E.P. should not randomly be taking samples. Testing should always answer a question about your home and/or influence your next steps.
  • How do you use that testing to inform your recommendations?
    • Testing should always answer a question you have about your home or influence your next steps. It should confirm if something is or is not going on in the building. Any data from a test should be combined with information from the thorough physical inspection in order to paint the most accurate picture of what might be going on in the home. Ultimately the data from these tests will help the IEP write the recommended protocol if remediation is needed.
  • Do you test for and address cross contamination in the rest of the home? If so, how?
    • Mold spores, fragments, and in some cases, mycotoxins, can easily move around a room or building on air currents, people, pets, and possessions. For example, mold growing in the corner of your basement can lead to cross contamination of other areas of the home like adjoining rooms, other levels, and even your HVAC system. These spores, fragments, and mycotoxins can impact your health.  It is important to understand how these contaminants may have impacted other areas of the home so they can be successfully removed. Testing for cross contamination is sometimes referred to as progressive sampling.
  • If remediation is done, what does the post-remediation verification (testing) look like? What clearance criteria is used to decide if a remediation project was successful?
    • The goal of post-remediation verification is to confirm if the remediation was successful and met the expected goals. Like the initial inspection and assessment of your home, post remediation verification includes a visual inspection and testing of the home. A sampling (testing) strategy is determined the day of post-remediation verification based on what the I.E.P. finds during the inspection of the remediated areas. The I.E.P. should perform the visual inspection first. Based on what is discovered during the visual inspection, the I.E.P. should discuss with you which testing options are appropriate for your situation. Typically, the post testing may mirror the testing done during the initial inspection and assessment.
      A remediation project may fail simply because the visual inspection shows mold, dirt, or debris inside the containment. Be sure you, your I.E.P., and your remediation company agree prior to any work beginning about what circumstances will result in a project passing or failing post-remediation verification (testing). Be sure this agreement is in writing.  


Questions about their background:

  • What certifications and training have you received?
    • There are several organizations that offer certifications in the indoor air quality industry that are specific to assessing residential properties. In addition to the list of the most widely accepted certifications, it is important to check state regulations as some require licenses to perform mold inspections. The ACAC and NORMI websites are a good place to start your search for an I.E.P.
      •  ACAC https://www.acac.org/find
        • CMI (counsel-certified microbial investigator)  
        • CIE (counsel-certified indoor environmentalist) 

      • NORMI  https://www.normipro.com/search-certs.php
        • CMA (certified mold assessor) 
  • Have you worked with sick or sensitive individuals before? Does your process or recommendations change in that case? If so, how?
    • It’s recommended to work with someone who understands how those who are sick or sensitive to mold may be affected by seemingly small amounts of contamination.  

Questions about remediation:

  • What standards or guidelines do you use to develop your protocols and recommendations?
    • There are no federally mandated standards in the United States. The ANSI IICRC S520 provides a reliable and accredited set of standards that can serve as a starting point for your remediation project.  
  • What does a remediation protocol that you write typically entail?
    • A remediation protocol should outline the entire scope of the work to be performed including the standards and procedures to be followed. It should include information about proper engineering controls (like containment and pressure), how the home and workers will be protected, and specifics about how demolition, removal, and cleaning inside the containment will occur.

Questions about reports:

  • What information can I expect in my report? Are pictures included? If remediation is warranted, is a remediation plan included or is that an additional fee? 
    • You should get a detailed report that includes pictures, test results, observations about the entire home. The report should include the analysis and explanation of any test results as well as make recommendations about next steps.
  • How long will it take to receive my written report?
    • Time will vary. Be sure you are comfortable with the timeline for your project.
  • What is included in the post-remediation report?
    • A post-remediation report should include observations from the visual inspection, test results, analysis, and a final statement about if the remediation project passed testing. 

Questions related to cost:

  • What are your fees for an initial inspection? What is included in that cost? What is not included in that cost?
    • Cost can vary greatly depending on the location and scope of the project. Be sure you are clear on prices and ask about any hidden or additional fees. A thorough assessment with a strategic sampling (testing) plan with a variety of sample types can start at a few thousand dollars and increase depending on the condition of the building and size of the home. 
  • How much does each type of test cost? Can you tell me ahead of time how many tests you will run?
    • Be sure to understand how much each type of test costs. Unfortunately, it’s hard to say how many tests will need to be run in a home until the assessment occurs. Discuss with your I.E.P. ahead of time how and when your I.E.P. will run a test and if they should notify you once on site where they will plan to test.  
  • How much does post testing typically cost?
    • Post-remediation testing is an additional and important cost. Based on the scope of the work, you should be able to get a pretty good idea of the types and number of samples that will be needed.

For more information on the role of an Indoor Environmental Professional, be sure to check out these resources: