WL400 Water Level Sensor

Price$941.00 (US Only)



In Stock 0 - Available for Backorder

Accurate and reliable Water Level pressure transducer designed for remote monitoring and recording of water level and pressure data in groundwater pumping and sludge tests, stormwater flood analysis, and run-off, as well as surface water irrigation canals, streams, and river gauging.

  • Overview

    Global Water's WL400 Water Level Sensor provides highly accurate water level measurement for various applications, including those in severe environments. The submersible pressure transducers have a dynamic temperature compensation system, enabling high accuracy measurements over a wide temperature range. The water level sensor is easily adapted to all dataloggers, telemetry, monitoring equipment, and displays.

    Multiple depth ranges are available from 3 to 500 feet of water level change.

    Key Features:

    • Sensor compatible with most monitoring equipment
    • Highly accurate water level measurements
    • Not affected by foam, wind, or rain
    • Wet-wet transducer eliminates vent tube concerns
    • Automatic barometric pressure and temperature compensation
    • Well-built to support depths of 3ft to 500 ft
    • Can measure level and temperature

    The Water Level Sensor's submersible pressure transducer is fully encapsulated with marine-grade epoxy so that moisture can never leak in or work its way down the vent tube to cause drift or level sensor failure (as is the case with other pressure sensors). The water level sensor uses a unique, highly flexible silicon diaphragm to interface between water and the sensing element. This silicon diaphragm protects the water level sensor's electronics from moisture and provides each sensor with exceptional linearity and very low hysteresis. The design of the submersible pressure transducers eliminates the issues associated with metal foil diaphragms, which tend to crinkle and stretch out over time, causing drift, linearity, and hysteresis problems. The water level sensor also has automatically barometric compensation due to the attached vent cable. It is protected by a stainless steel micro-screen cap, making fouling with silt, mud, or sludge virtually impossible. The water level sensor's design is great for all saltwater applications, including tide level monitoring, floating docks, etc.

    Each submersible pressure transducer has a two-wire 4-20 mA output signal linear with water depth. From 10 to 36 VDC is required to operate the water level sensor so that the level sensors can be operated from common 12 VDC battery systems. The 4-20 mA signal can run up to 3,000 ft from the submersible pressure transducer to the logging device. Common twisted pair or electrical extension cord wire may be spliced to the vented cable once the cable is out of the water. The 4-20 mA signal may be converted to 0.5 to 2.5 VDC by dropping the current signal across a 125-ohm resistor.    

  • Specifications
    Sensing Element Specifications  
    Sensor Element Silicone Diaphragm, Wet/Wet Transducer

    0-3', 0-15', 0-30', 0-60', 0-120',0-250' 

    Linearity and Hysteresis ±0.1% FS

    ±0.1% FS at constant temperature, ±0.2% over 35° to 70°F range

    Overpressure Not to exceed 2 x full-scale range Resolution: Infinitesimal (Analog)


    4-20mA, or 0.5 to 2.5 VDC across 125-ohm resistor

    Supply Voltage


    Current Draw  Same as sensor output.
    Warm-Up Time

    10 ms minimum

    Operating Temperature -40° to +185°F
    Weight 1/2 lb.
    Compensated Temperature Range

    30 to 70°F submerged, automatic barometric compensation

    Housing Specifications  
    Material 304L SS 

    up to 5 1/2” long x 13/16" diameter

    Weight ~115g (4 oz)
    Cable Specifications  
    Conductors 4 each 22 AWG
    Jacket Material

    87A shore hardness Polyurethane

    Optional Jacket Fluorinated Ethylene Propylene (FEP) Teflon
    Cable O.D. 7.8mm (0.307”)
    Vent Tube HD Polyethylene

    Aluminum Mylar

    Temperature Range -30 to 85°C (-22 to 185°F)


    ~65g/m (0.7 oz/ft) 

  • FAQs

    What are the best applications for the WL400?

    • Ideal for static level water monitoring and water depths in rivers, streams, groundwater, coastal, and other surface water applications.
    • Depth monitoring for wells and/or sludge testing.
    • Water elevation monitoring between different sites.
    • For monitoring water level usage within industrial plants.

    What makes the WL400 different from other YSI water level instruments?

    • The WL400 is almost identical to the WL16 except it doesn’t include internal datalogging capabilities.
    • It utilizes analog outputs instead of digital outputs.
    • It can record temperature and level simultaneously
    • It comes equipped with a silicon diaphragm, unlike the WL450 which utilizes a stainless steel or Titanium diaphragm

    What type of depths and cable lengths are available

    • Depth ranges: 3’,15’,30’,60’,120’,250’,500’
    • Cable lengths: 3’,25’,50’,75’,100’,125’,150’,200’,300’,500’

    How is the WL400 calibrated? And is it certified?

    The WL400 is calibrated at the YSI facility and gets a quality certification upon shipment.

    What are the typical power requirements and battery life?

    The WL16 is powered by (2) replaceable 9V batteries with the unit requiring at least 12 volts of power, and can generally be in field service use 6 to 7 months before having to change batteries.

    How often do I need to calibrate the equipment in the field?

    We recommend once a year if possible.

    How do I field calibrate my equipment?

    Pictures and steps can be found in the WL400 Manual

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