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.

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  • 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


Total length: 147 cm
DCT length: 63.5 cm
DCT (inside) diameter: 25.4 cm
Reservoir length: 81.3 cm
Reservoir (outside) diameter: 11.5 cm
Access tube length: 180 cm standard, customizable
Access tube, outside diameter: 6.0 cm (2" schedule 40 PVC)
Sample evacuation tube: 1.27 cm OD X 0.79 cm ID X 3 m length; custom lengths available upon request
Mass: 20 kg with stainless steel DCT, 14 kg with PVC DCT


Drainage: 0-61 mm bottom of wick and 61-100 mm top of reservoir chamber
Water depth: 0 to 3.5 m
Electrical conductivity: 0 to 120 dS/m
Temperature: -11 to 49 °C


Drainage: 0.2 mm
Water depth: 1 mm
Electrical conductivity: 0.001 dS/m
Temperature: 0.1 °C


Drainage: ±1.4 mm
Water depth: ±0.5% of full scale @ 20 °C
Electrical conductivity: +0.01 dS/m or + 10 % (whichever is greater)
Temperature: ±1 °C

Suction at intake

110 cm (11 kPa)

Solution collection capacity

3.1 L (6.1 cm of drainage) to bottom of wick
Additional 5.1 L (10 cm of drainage) of reserve capacity in wick chamber

Solution collection surface area

507 cm2 (25.4 cm inside diameter)

Wetted material

DCT (standard): 304 Stainless Steel 11 gauge
DCT (optional inert material): PVC
Wick: dry-fired fiberglass
Root inhibitor: Treflan (BioBarrierTM), removable upon request
Sample evacuation tube: Polyethylene
Hydraulic bridge material: Diatomaceous Earth (DE)
All other parts: PVC

Operating temperature

0 to 50 °C (Pressure transducer cannot be allowed to freeze while submersed.)

Power requirements

3.6 - 15 VDC, 0.03 mA quiescent, 0.5 mA during 300 ms measurement

Measurement time

300 ms (milliseconds)


Serial TTL, 3.6 volts levels or SDI-12

Connector types

3.5 mm (stereo) plug, or stripped & tinned lead wires (3)

Cable length

10 m standard; custom lengths available upon request

Data logger compatibility (not exclusive)

METER ZL6, Em50/60 Series, ProCheck, Campbell Scientific

Software compatibility

ZENTRA Cloud, ZENTRA Utility, ECH2O Utility (rev 1.64+), DataTrac 3 (rev 3.4+)

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


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