The Tool Every Home Inspector Needs

What does it take to have a happy customer? How about a quality moisture meter?

Let’s say you notice a water stain in a customer’s home. Since you don’t use a moisture meter, you recommend evaluation by a professional. So, the customer hires professionals, one after another—plumber, roofer, HVAC technician—to determine whether a leak still exists.

Turns out, no leak.

But you have an upset homeowner who is in over $2,000.

This scenario comes from Martin Willes, an InterNACHI certified professional inspector, who finishes his story with the following comment: “A moisture meter would have told you if that leak was active on the day of inspection.”

Could a moisture meter make the difference between being an average home inspector and a thorough one? Let’s find out as we cover:

Why home inspectors need a moisture meter

A home inspector placing a moisture meter on damaged wood

Moisture meters are essential tools for home/building inspections because of how pervasive moisture issues are. They allow you to be more thorough and efficient—leaving clients confident and satisfied with your services.

Notice what long-time home inspector Randy Mayo had to say about it on the 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[s] that have leaked. My moisture meter, thermal camera, and flashlight are my three main tools.”

Inspector Randy Mayo says, In 27 years I can say with confidence that 95% of all issues in a home are water related

Do you also have a moisture meter among your inspection tools?

By indicating high moisture levels, it’ll help you flag potential issues that could become major later on if not dealt with.

And it can assure your clients that their homes/buildings are not at risk for water intrusion.

So what are some specific uses of a moisture meter?

Ways home inspectors can use moisture meters

Mold on a ceiling due to a moisture issue

Moisture meters help inspectors determine the risk of a moisture issue. Of course, these meters aren’t able to diagnose the issue. But they can indicate the possibility of a leak, mold, or mildew.

If you notice a water stain or other evidence of a moisture issue, the meter can help you investigate. Take readings of that location and around it to help you know whether the leak has dried or whether there might still be an active leak.

In this way, you’ll prevent the homeowner from having to seek other services unnecessarily.

ASHI, the American Society of Home Inspectors, states the following in its guidelines and standards:

“The inspector shall inspect readily accessible, visually observable, installed systems and components listed in this Standard.”1

This includes walls, ceilings, and floors.2 But inspectors are not required to determine “the conditions of systems and components that are not readily accessible.”3

However, good inspectors will often go above the bare minimum, especially if they see any signs of moisture intrusion, such as:

  • Discoloration
  • Warping
  • Mold growth
  • Deteriorating caulk, sealant, or paint
  • Standing water

Here are some things a moisture meter can help you check:

  • Walls and floors around cabinets, appliances, faucets, pipes, and windows
  • Subfloors, if you’re dealing with a flooding situation or major water damage
  • Basement walls or floors

If major water damage has occurred, taking moisture measurements will help determine if a home/building can be occupied again.4

That’s how Ashly L, a reviewer on Amazon, used her Bessemeter moisture meter:

“Due to flooding this allows me to see how much moisture is in our wood, etc. A must for property management!”

Now that we know the different ways you can use a moisture meter for inspections, let’s look at how to use the meter itself.

How to use a moisture meter

If you’re new to home inspection, this may be your first time using a moisture meter. And no worries! In this section, we’ll guide you on how to use one.

Simply take these basic steps:

  1. Check calibration
  2. Use the correct mode
  3. Take multiple readings

If you’re already familiar with moisture meters, skip to the last section of this article. Otherwise, here we go!

1. Check calibration

A Bessemeter moisture meter on a calibration verification reference

To be confident that you’re getting accurate meter readings, check the calibration of your meter before you start using it. Quality meters will have some way to verify calibration—whether a built-in calibrator or a calibration verification reference tool.

2. Use the correct mode

If you’re measuring wood, place your moisture meter in that mode and input the correct species number. Bessemeter moisture meters come with a manual that has a comprehensive list of wood species with numbers to input for each one.

If you’re measuring other materials, such as drywall (gypsum) or concrete, use the meter’s relative mode.

In relative mode, you won’t get accurate readings of moisture content. But you’ll be able to compare relative levels of moisture—the wetness and dryness of various areas. This is the function that most home inspectors need anyways.

And that brings us to the final step:

3. Take multiple moisture readings

Especially when using relative mode, taking just one measurement won’t be helpful to you. Instead, you’ll first need to measure areas you know to be dry. The numbers you get there will provide a baseline for measuring other areas.

Inspector Michael Egbert gives the following advice:

“Look for a difference between your suspect area and the surrounding areas of the same material…. If an area of drywall below a poorly flashed window reads 25, and the drywall a foot or two to the sides of the window reads 5, the window is likely leaking.”

 Inspector Michael Egbert advises when using a moisture meter to look for a difference between your suspect area and the surrounding areas

Another point Egbert makes is the importance of investing in a quality moisture meter.

Here’s some guidance on what to look for.

The best moisture meter for the job

A pin-type moisture meter

You have two types of moisture meters to choose from for your work as a home inspector:

  1. A pin-type moisture meter
  2. A pinless moisture meter

Pin meters measure moisture through two electrodes (pins) inserted into the material. The downfall of these kinds of meters is that they poke holes into the surface you’re measuring.

In contrast, a pinless meter (sometimes called a noninvasive meter) uses electromagnetic technology to scan the material for moisture. This one allows you to measure materials much more quickly because you can scan them without pushing in pins.

And most importantly, no pinholes!

Many home inspectors prefer a pinless meter for that reason.

Brian Cawhern is one of them. He commented the following on an InterNACHI thread in which an inspector had used a pin meter:

“Some nice holes you poked into their [the client’s] ceiling, might want to consider a pinless meter for finished surfaces.”

NACHI inspector Brian Cawhern recommends using a pinless moisture meter rather than a pin type

Brian Cawhern recommends not putting holes into people's finished surfaces when there are non-destructive options available

Bessemeter’s wood moisture meters are a great option for home inspectors because they have a relative mode that works well for detecting moisture in a variety of materials.

You can also choose a meter with the depth you need: ¼-inch, ¾-inch, or dual-depth.

See our pinless meter buying guide to find the best one for you.

Take your home inspections to a new level

Convinced you need a moisture meter for your work as a home inspector?

With it, you can:

  • Identify potential moisture issues
  • Work more effectively and thoroughly
  • Save clients money
  • Grow your reputation

As you begin using a moisture meter, see our tips for using a moisture meter to ensure success!

  1. The Standard of Practice for Home Inspectors and the Code of Ethics for the Home Inspection Profession, ASHI, section 2.2. ()
  2. Ibid., section 10.1. ()
  3. Ibid., section 13.2. ()
  4. Gromicko, Nick, and Shepard, Kenton, “Moisture Meters for Inspectors,” InterNACHI. ()