On Piezometers and Monitoring Wells
The word “piezo” in Greek means “pressure” and
“meter” means to measure. Thus “piezometer” means a device to measure
In the field of study of aquifers, we use piezometers to measure the pressure of the groundwater at various locations and depths. Such piezometers usually consist of a small pipe or tube, the end being under the water face, thus allowing for the water to move up and down inside the tube in accordance with the water pressure in the aquifer where the piezometer is inserted.
Here’s a simplified diagram of a piezometer:
In the environmental field we use groundwater monitoring wells to collect water samples from the aquifer. Here is a simplified diagram of a groundwater monitoring well:
The essential difference between piezometers and monitoring wells is
that in the monitoring well we have a wide range screen (usually from
20 feet below the water table to 10 feet above the water table).
The screen takes into consideration the fluctuations with groundwater
table and allows for free petroleum products that may reside at the
water table to enter the well. In the case of a piezometer, this can’t
Similarly, soil gas probes are not piezometers as
they measure no pressure. First off, these probes are installed ONLY
in the soil, never in water. Secondly, their function is only the
collection of migratory vapors for later sampling. Here’s a typical
diagram of a soil-vapor probe.