Do I Have to Use a Moisture Meter for Home Inspections?

Though moisture meters are not required for home inspections, many home inspectors go the extra mile and use a moisture meter to help their clients know of any possibilities for moisture issues. The meter gives extra insight that might not be noticeable to the naked eye or touch.

But don’t take our word for it.

We’ll look at industry standards and see what certified home inspectors have to say.

You’ll learn:

• How many home inspectors approach moisture testing
• Whether certain moisture tests are required during a home inspection
• Industry standards for moisture meter use
• Whether you should use a moisture meter

Let’s start by looking at how most home inspectors might answer this question.

What do home inspectors do about moisture testing?

Though using moisture meters isn’t required for inspections, many home inspectors see them as crucial to their work. Having a moisture meter allows them to be thorough. While moisture meters can’t diagnose an issue, they can indicate the potential for one—and being able to share that information with a client adds extra value to an inspection.

Kevin Leonard is a Certified Master Inspector with InterNACHI (International Association of Certified Home Inspectors). If he finds water stains or dampness in a wall of a home, a moisture meter helps him to know whether that stain still contains moisture, which can help identify an active leak.

“If there is an active leak, it’s obviously more serious than a dry stain that may have been there for 10+ years before they last replaced the roof. A good moisture meter is a must-have tool for a home inspector,” he shares.¹

Moisture meters can’t give exact readings on all types of materials, but when used in “relative mode,” they can indicate areas of higher and lower moisture. Doing comparative measurements can still provide very useful information about what could be going on under a surface.

Randy Mayo, another InterNACHI inspector, doesn’t take any chances.

Here’s what he had to say about it on an InterNACHI forum:

“In 27 years I can say with confidence that 95% of all issues in a home are water-related, unless you live in the middle of a desert. Leaking through the roof, no gutters, clogged gutters, water that drains towards the foundation, basements that leak, water under the crawlspace, and kitchens and bathroom that have leaked. My moisture meter, thermal camera, and flashlight are my three main tools.”²

Though meters aren’t required, home inspectors find peace of mind in using them to verify moisture levels during their moisture checks.

Are certain moisture tests required during a home inspection?

Specific moisture tests aren’t required, though home inspections involve inspecting for specific things in specific areas of a home—walls, ceilings, floors, windows, etc. National and state standards of practice list these out.

While inspecting these areas, home inspectors will look for signs of moisture. Though their role isn’t to diagnose an issue, they can indicate the possibility of one.

Some signs of potential moisture issues are:

• Discoloration
• Warping
• Mold growth
• Deteriorating caulk, sealant, or paint
• Standing water
• Water stains
• Anything that feels wet
• Leaks
• Musty smells
• Fogged up windows
• Rust or corrosion of anything metal

And even if a home doesn’t have a current moisture problem, some issues can lead to them. For example, a bathroom exhaust fan that doesn’t work could result in high humidity levels and excess moisture in the bathroom. Or, breaks in weatherstrips or window seals could lead to leaks when it rains.³

Ben Gromicko, a certified inspector with InterNACHI, also checks for the following external issues that could lead to moisture issues⁴:

• Improperly installed or damaged flashing
• Cracks or openings in the chimney
• Missing shingles
• Clogged gutters
• No flashing over the windows or on decks
• Rotting windows or door corners
• Downspouts that aren’t diverting water from the house
• Improper door tread that allows water in

Ben aims to find any “opportunities where water may come through.” He uses a moisture meter any time he notices signs of moisture.⁵

So…if moisture meters are so helpful, why aren’t home inspectors required to use them?

Let’s see if we can get an answer by looking at the inspection standards for moisture meters.

Industry standards for moisture meter use

Officially, industry standards don’t require the use of a moisture meter during a home inspection.

ASHI (American Society of Home Inspectors) doesn’t mention moisture meters in its standard of practice and simply states that, “the inspector shall inspect readily accessible, visually observable, installed systems and components listed in this Standard.”⁶

InterNACHI’s standard of practice states that many inspection tools are not required:

“The inspector is not required to operate…moisture meters, gas detectors, or similar equipment.”⁷

The same seems to be true for home inspection standards of many states. In many cases, inspectors are required to report signs of water and water damage, though they aren’t required to be “technically exhaustive.”⁸

The glossary at the back of the standard defines “technically exhaustive” as involving “the use of measurements, instruments, testing, calculations, and other means to develop scientific or engineering findings, conclusions, and recommendations.”⁹

Though the inspector wouldn’t be liable in either case, it’s clear who would be more trusted and highly recommended.

In this way, many U.S. states only require “visual observation” for home inspection.¹⁰

But let’s think about what this means. Inspectors are only required to report on the problems they see. They’re not liable for the problems they don’t see, and yet…that doesn’t mean the problems aren’t still there.

InterNACHI says inspectors don’t have to use gas detectors. But let’s say an inspector doesn’t use a gas detector which causes them to miss a deadly odorless gas like Carbon Monoxide.

Would clients appreciate the inspector who went above and beyond and used a gas detector to keep them and their homes safe? Or would they be satisfied with the inspector who merely relied on visual inspection?

The choice to use moisture meters works the same way.

When you use relative mode, wood moisture meters will enable you to detect the presence of moisture in non-wooden materials like drywall. These moisture readings can indicate areas with higher levels of moisture that you note for further investigation.

In their baseline mode, wood moisture meters can perform thorough moisture inspection by giving you exact moisture measurements— the moisture content of the wood itself.

By keeping a close eye on water intrusion with these meter readings, you can help prevent moisture damage. Homeowners will thank you for your thorough building inspection as you double-check the building materials of their home with a moisture meter.

Should you use a moisture meter?

A moisture meter allows you to more easily and thoroughly do your due diligence as a home inspector. You’ll be able to note areas that need further investigation, even if they don’t (yet) pose a visible threat. Homeowners, buyers, builders, and real estate agents will not have to worry about potential water problems being missed just because moisture testing isn’t technically required.

To learn more of the details about using moisture meters in home inspections,

If you’re not sure yet which moisture meter is best for you and your business,