Drain Gauge G3 Lysimeter

Dependable Deep Drainage

Drain Gauge G3 Lysimeter

Characterize variability without stressing your budget

The only accurate way to understand the amount of nutrients or chemicals leaching into the groundwater is to directly measure deep drainage. Large, controlled-tension weighing lysimeters are the most accurate way to make this measurement, but the considerable power and funding requirements of a weighing lysimeter plus the complexity of setup and maintenance may mean you need another option. If you want to characterize variability at a number of locations but don’t have the funding for a collection of large weighing lysimeters, the Drain Gauge G3 has you covered.  

Incredibly easy to use

The Drain Gauge G3 allows you to deploy multiple units to cover a large area at an affordable cost. It’s an incredibly easy-to-use lysimeter that provides dependable monitoring of leaching, drainage, and recharge without the complexity of larger systems. This means you can instrument entire agricultural fields to better quantify variability. The G3 was deliberately engineered to be installed below the plow layer, so growers can perform normal operations directly over the instrument, which eliminates problems like edge effects. Plus, the Drain Gauge G3 can be combined with METER soil moisture sensors and precipitation gauges to estimate the total water balance more accurately than methods which only guess at deep drainage as a residual.

Understand leaching at a deeper level

The Drain Gauge G3 is a passive-capillary lysimeter that determines the volume of water and chemicals draining from the root zone into groundwater. Once installed below the root zone, water samples are easily collected through the surface port for analysis of chemicals, fertilizers, and other contaminants. Not only is the Drain Gauge constructed from inert materials so it won’t react with compounds collected in the sample reservoir, it also features a sealed design, which allows it to work in both saturated and unsaturated conditions.

Almost no power or maintenance required

One challenge with lysimeter measurements is that water can flow around receptacles buried in the ground. Unlike traditional pan lysimeters, the G3 corrects for this problem by using an innovative duct and wick design to keep soil tension in the soil column similar to that of the natural soil at the installation site. After installation, the G3 is practically effortless. It requires almost no power and no maintenance other than periodically pulling samples.

Engineered to fit your needs

The Drain Gauge is designed to be flexible to fit your unique application. A stainless steel or PVC divergence control tube holds the soil monolith. Stainless steel is recommended for taking an intact soil monolith, and PVC is recommended for conditions where heavy metals are leaching.

For most applications, we recommend using the add-on Drain Gauge Sensor to measure conductivity, temperature, and depth of the collected sample and to help determine when to empty the sample reservoir. The sensor also provides time-series drainage data, enabling you to correlate drainage with irrigation, fertilization, or other events. For installation sites that are remote or have high drainage rates, use the G3 AutoPump to take samples or empty the reservoir automatically. The sensor and AutoPump can be easily integrated with pre-installed units and are ideal for use with our new ZL6 data logger.

Dependability without complexity and expense

The Drain Gauge G3 accurately measures deep drainage without the hassle and expense of installing a complicated weighing lysimeter. Get simplified sampling, easy data collection, minimal maintenance, dependable data, and excellent representation of variability—all at price you can afford.

Request a quote Contact us


  • Completely sealed system protects from high water tables
  • 6.1 cm drainage capacity allows for large sampling volumes
  • Monitor solute fluxes with optional EC sensor 
  • Can be used with the optional AutoPump to automatically draw samples on remote or high drainage deployments


View GSA details



Range: 0−61 mm bottom of wick, 61−100 mm top of reservoir chambers
Resolution: 0.2 mm
Accuracy: ±1.4 mm

Water depth

Range: 0-10,000 mm
Resolution: 1 mm
Accuracy: ±0.05% of full scale at 20 °C

NOTE: Depth measurement accuracy assumes no abrupt temperature variations.


Range: −40 to +60 °C
Resolution: 0.1 °C
Accuracy: ±1 °C

NOTE: Ice formation within the G3 Drain Gauge will ruin the pressure transducer. Remove the HYDROS 21 sensor if the water temperature could drop below 0 °C (32 °F).

Bulk electrical conductivity (EC)

Range: 0−120 dS/m
Resolution: 0.001 dS/m
Accuracy: ±0.01 dS/m or ±10%, whichever is greater

NOTE: The EC measurement is corrected to a standard temperature of 25 °C.



DDI serial or SDI-12 communication protocol

Data logger compatibility

METER ZL6 data loggers and any data acquisition system capable of 3.6- to 15.0-VDC power and serial or SDI-12 communication


G3 Drain Gauge dimensions

Length: 16.0 cm (6.3 in)
Width: 3.3 cm (1.3 in)
Height: 0.8 cm (0.3 in)
Mass: 20.0 kg (44.0 lb) with stainless steel DCT
14.0 kg (31.0 lb) with PVC DCT

DCT dimensions

Length: 62.5 cm (24.6 in)
Inner diameter: 25.4 cm (10.0 in)
Outer diameter: 26.4 cm (10.4 in)
Width: 3.3 cm (1.3 in)

Reservoir dimensions

Length:180.0 cm (70.9 in) standard, custom lengths available
Outer diameter: 6.0 cm (2.4 in)

Access tube dimensions

Length: 81.3 cm (32.0 in)
Outer diameter: 11.5 cm (4.5 in)
Material: Schedule 40 PVC

Sensor dimensions

Length: 9.0 cm (3.5 in)
Diameter: 3.4 cm (0.5 in)

Sampling tube dimensions

Length: 5.0 m (196.9 in) standard, custom lengths available
Outer diameter: 6.0 mm (0.5 in)
Material: Polyethylene

Operating temperature range

Minimum: 0 °C
Maximum: 60 °C

NOTE: Sensors may be used at higher temperatures under certain conditions; contact Customer Support for assistance.

Cable length

10.0 m (standard)
20.0 m
40.0 m (maximum)

Cable diameter

4.20 mm (0.165 in) with a minimum jacket of 0.76 mm (0.030 in)

Connector type

Stereo plug connector or stripped and tinned wires

Connector diameter

6 mm (0.24 in)

Conductor gauge

22 AWG/24 AWG drain wire


Supply voltage (VCC to GND)

Minimum: 3.6 V
Maximum: 15.0 V

Digital input voltage (logic high)

Minimum: 2.8 V
Typical: 3.6 V
Maximum: 5.0 V

Digital input voltage (logic low)

Minimum: –0.3 V
Typical: 0.0 V
Maximum: 0.8 V

Digital output voltage (logic high)

Typical: 3.6 V

Power line slew rate

Minimum: 1.0 V/ms

Current drain (during measurement)

Minimum: 0.5 mA
Typical: 4.0 mA
Maximum: 8.0 mA

Current drain (while asleep)

Typical: 0.3 mA

Power up time (DDI serial)

Maximum: 200 ms

Power up time (SDI-12)

Typical: 430 ms
Maximum: 450 ms

Power up time (SDI-12, DDI disabled)

Typical: 165 ms
Maximum: 185 ms

Measurement duration

Typical: 150 ms


Manufactured under ISO 9001:2015
EM ISO/IEC 17050:2010 (CE Mark)

California requires the following notice:

⚠️ WARNING: This product may contain chemicals including ethylene glycol, lead, nickel, styrene and cadmium, which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov



Have a question or problem? Our support team can help.

We manufacture, test, calibrate, and repair every instrument in-house. Our scientists and technicians use the instruments every day in our product testing lab. No matter what your question is, we have someone who can help you answer it.

Phone US: +1 509-332-5600
Phone Europe: +49 89 12 66 52 0


Read Knowledge Base Articles