Oftentimes, water problems in a residence or business are very evident. For example, directly after a flood, sewage backup, or broken pipe, water and even other substances in a property are obvious. With that said, there are also situations in which potentially damaging moisture issues in a home, business, or other location are not readily evident. As a result, water remediation specialists, contractors, and other professionals take advantage of moisture meters in order to ascertain the presence of potentially damaging moisture in a property. The three most commonly used moisture meters are:

  • Pin moisture meters
  • Pinless moisture meters
  • Thermo-hygrometers

Areas in a Building Tested for Moisture

Before diving into a discussion of the three most commonly used moisture meters, basic information about test sites in a building is important. While any location in a residence, business, or other structure can have a moisture problem, there are a number of specific areas in a residence, business, or other location at which water or moisture more commonly is an issue. These include:

  • Flooring
  • Carpets
  • Wood flooring
  • Laminate
  • Tile
  • Walls 
  • Drywall
  • Insulation
  • Ceiling
  • Attic

Pin Moisture Meters

Pin moisture meters are among the most commonly used pieces of equipment associated with moisture detection and water remediation today. Pin moisture meters have been in use in the United States and around the world since the 1940s.

Three important pieces of data can be derived from the use of pin moisture meters. These are:

  • Location of pockets of high moisture
  • Average moisture content
  • Full range of moisture content 

Pin moisture meters operate using what is known as the principle of electrical resistance. The user of this type of meter pushes a pair of pins into the object or surface for which moisture monitoring is desired. 

When the pins reach the desired depth, the user activates the device. What this means is that one of the pins is activated to generate an electrical current. 

The second pin operates as a receiver. The process determines the amount of resistance that exists in regard to the electrical current. This resistance measurement is conveyed as a value on the reader associated with the pin moisture reader.

In order for a pin moisture meter to provide accurate results, calibration is crucial. A pin moisture meter must be calibrated specifically to the type of material that comprises the object or area being tested. 

Pinless Moisture Meters

In many situations, a home or business owner doesn’t want to have the surface of an object or location inside a structure penetrated by the pins associated with the moisture meter just discussed. These individuals don’t want what arguably are unsightly puncture holes left in the aftermath of a pin moisture meter examination.

As the name indicates, a pinless moisture meter doesn’t rely on pins to operate and collect data. Rather, a pinless moisture meter sends an electromagnetic wave into the material being measured for moisture.

The meter interprets fluctuations in the electromagnetic wave. These fluctuations can provide useful data regarding the presence and extent of moisture. 

There are benefits associated with pinless moisture meters beyond the fact that they do not leave puncture holes behind after use. These include:

  • Ability to scan large areas quickly
  • Relatively simple to operate
  • Effective on surfaces made of materials too tough for pin penetration

Despite the real benefit of not leaving puncture holes, pinless moisture meters typically are not the measuring or reading device of first choice. This is the case because of some more negative aspects associated with pinless moisture meters. The downsides to using pinless moisture meters include:

  • They require a flat surface to obtain an accurate reading
  • Material being measured must be thick enough to accommodate the electromagnetic wave.
  • Existing surface moisture can skew test results
  • Limits to scanning depth can result in moisture conditions being overlooked


The third type of moisture meter is the thermo-hygrometer. A thermo-hygrometer measures the overall ambient conditions in a particular room as opposed to the moisture level in a specific object in a room. In addition, as part of collecting data, ambient conditions outside of a specific room but within the structure must also be collected. Finally, ambient conditions out of doors next to the room being tested for moisture must also be tested or examined with a thermo-hygrometer.

Four factors must be taken into consideration when using a thermo-hygrometer to identify and measure moisture:

  • Temperature
  • Sensor tolerance
  • Calibration
  • Operating and storage conditions

A thermo-hygrometer is the most complicated to use of the three moisture meters discussed here. While the first two moisture meters can be utilized by people undertaking do-it-yourself projects, a thermo-hygrometer will require a bit more in the way of training. The potential for error is more likely with a thermo-hygrometer than is the case with the other two moisture meters. The inability to really understand how to operate a thermo-hygrometer can result in very unhelpful readings.