HOBO Water Level Logger


Onset HOBO Logger Measures and Records Water Level and Temperature

The water level data logger is designed to accurately measure and log water levels and temperatures in wells, streams, lakes, wetlands and tidal areas. With no cumbersome vents, this logger is completely self-contained. The logger features lightning protection, ceramic pressure sensor, programmable start time and date, data storage up to 21,700 total samples, up to 8 simulataneous sampling rates and a 5 year battery life.

Available in Stainless Steel Housing or Titanium Housing Versions.
Available in 0 to 13ft, 0 to 30ft, 0 to 100ft and 0 to 250ft Depth Versions.

Deluxe Barometric Pressure and Starter Kits Available

Required with the Water Level Data Logger
>> HOBOware™ Pro Software Kit
>> Optic USB Base Station or HOBO Waterproof Shuttle Data Transporter

>> All depth specifications assume use in water at sea level
>> For deployment in saltwater see our application note on 316 stainless steel and possible corrosion in saltwater or contact us to discuss your application
>> Titanium Version Recommended for Saltwater Deployment

Water Level Logger Features

  • HOBOware™ software provides easy conversion to accurate water level readings, fully compensated for barometric pressure, temperature and water density
  • Use either a second water level logger or a HOBO Weather Station for barometric compensation when needed (one barometric data set can be used with all water level loggers in that area)
  • HOBOware provides comprehensive graphing, analysis and reporting
  • No-vent-tube design eliminates installation/maintenance issues and errors associated with vent tubes, such as bulkiness, desiccant maintenance, water in tubes, cuts, and decontamination between deployments.
  • Fully sealed housing insures many years of trouble-free operation
  • Optical/USB interface for years of reliable data offload in wet environments—no mechanical or elastomer connectors to fail
  • Streamlined housing for snag-free deployment in wells
  • Lightning protection—no long signal wires, and electronics are shielded in stainless steel housing
  • Durable ceramic pressure sensor
  • Simple wireline mounting makes it easy to hang logger in wells, hidden from vandals
  • Multiple-rate sampling allows faster sampling at critical times such as when pumping starts or stops
  • Includes calibration certificate of accuracy versus NIST-traceable standards at three pressure points (15, 21 and 29 psia)
  • Requires HOBOware Software Kit (PC and MAC Versions) and USB Optic Station

Water Level Logger Specifications

Data Storage Capacity 10,850 Pressure and Temperature Samples (21,700 Total)
Event Types
(stored to data file during logging)
Host PC Connection, Low Battery
Operating Range Temperature: -20°C to 50°C (-4° to 122°F)
Environment Waterproof; suitable for deployment in water or air, case materials resistant to fuels, solvents and lubricants. Titanium version recommended for saltwater deployments.
Wetted Materials 316 Stainless Steel (or Titanium for U20-001-01-TI), Viton® o-rings, acetyl cap, ceramic sensor
Battery Life 5 years with 1-minute or longer logging interval
Battery is Factory Replaceable
Battery Status Indication Battery status displayed at launch or with status screen; Battery voltage can be logged
Operation Indicator Red LED in communications window
Sampling Intervals 1 second to 18 hours; fixed- or multiple sampling rates —up to 8 user-specified sampling intervals
Start Modes Immediate Start, Programmable Start Time/Date
Offload Modes Offload while logging or stop and offload
Real-Time Clock ±1 minute per month 0°C to 50°C (32°F to 122°F)
Standards Compliance CE
Weight 210 g (7.4 oz)
Dimensions Logger: 24.6mm D x 150mm L (0.97" D x 5.9" L)
Mounting Hole: 6.3mm (0.25") Diameter
Water Level Measurement
Range** U20-001-01: 0-9 m (0-30 ft); 0-207 kPa (0-30 psia)
U20-001-02: 0-30 m (0-100 ft); 0-400 kPa (0-58 psia)
U20-001-03: 0-76 m (0-250 ft); 0-850 kPa (0-123 psia)
U20-001-04: 0-4 m (0-13 ft); 0-145 kPa (0-21 psia)
Factory Calibrated Range
(0°C to 40°C)
(32°F to 104°F)
U20-001-01: 69 to 207 kPa (10 to 30 psia)
U20-001-02: 69 to 400 kPa (10 to 58 psia)
U20-001-03: 69 to 850 kPa (10 to 123.3 psia)
U20-001-04: 69 to 145 kPa (10 to 21 psia)
Typical Accuracy
(± 0.01% FS)***
U20-001-01: 0.5cm (0.015 ft) water; ±0.05% FS 
U20-001-02: 1.5cm (0.05 ft) water; ±0.05% FS
U20-001-03: 3.8cm (0.125 ft) water; ±0.05% FS
U20-001-04: 0.3cm (0.01 ft) water; ±0.075% FS
Resolution U20-001-01: 0.21cm (0.007 ft), < 0.02 kPa (0.003 psi)
U20-001-02: 0.41cm (0.013 ft), < 0.04 kPa (0.006 psi)
U20-001-03: 0.87cm (0.028 ft), < 0.085 kPa (0.012 psi)
U20-001-04: 0.14cm (0.005 ft), < 0.014 kPa (0.002 psi)
Burst Pressure** U20-001-01: 310kPa (45 psia) or 18m (60 ft) depth
U20-001-02: 500 kPa (72.5 psia) or 40.8m (134 ft) depth
U20-001-03: 1200 kPa (174 psia) or 112m (368 ft) depth
U20-001-04: 310 kPa (45 psia) or 18m (60 ft) depth
** NOTE: Depth Range Specifications are nominal values based on using the logger at sea level.
*** NOTE: Typical Maximum error over the full temperature and pressure calibrated range.
Temperature Measurement
Range -20°C to 50°C (-4°F to 122°F)
Accuracy ±0.37°C at 20°C (0.67°F at 68°F);
±0.5°C (0.9°F) over -5° to 50°C (23°F to 122°F)
Resolution 0.1°C @ 20°C (0.18°F at 68°F);
0.2°C (0.36°F) over -5° to 50°C (23° to 122°F)
Response Time 3.5 minutes in water, typical to 90%
Stability (Drift) ≤0.1°C/year (0.18°F/year)

Optic USB Base Station

  • Optic USB Base Station offloads full logger in less than 30 seconds
  • Optical interface to logger eliminates unreliable connectors
  • Easy USB connection to PC
Description Part Number
HOBO Water Level Logger (0 - 30ft) U20-001-01
HOBO Water Level Logger with Titanium Housing (0 - 30ft) U20-001-01-TI
HOBO Water Level Logger (0 - 100ft) U20-001-02
HOBO Water Level Logger (0 - 250ft) U20-001-03
HOBO Water Level Logger (0 - 13ft) U20-001-04
HOBO Water Level Logger with Titanium Housing (0 - 13ft) U20-001-04-TI
Base Station & Coupler - 1 Required
Optic USB Base Station (includes Coupler) BASE-U-4
Waterproof Shuttle Data Transporter/Optic Base Station w/ Couplers - Requires HOBOWare Pro Software U-DTW-1
Required Software Kit - Required (Compare HOBOWare Versions)
HOBOware Pro Software Kit for Windows/Mac (includes Software and Cable) BHW-PRO-CD
Optional Accessories
Protective Housing for U24 and U20 Series Loggers HOUSING-U2X
Water Level Logger Carrying Case U20-CASE-1
1/16" Teflon-coated Stainless Steel Cable - 50 ft. CABLE-1-50
Coupler for U20 Water Level Loggers COUPLER2-B
1/16" Teflon-coated Stainless Steel Cable - 300 ft. CABLE-1-300
Crimp Sleeve (12-pack) for Cables CABLE-1-CRIMP
Custom USB Interface Cable CABLE-USBMB-HS

Waterproof Shuttle Data Transporter

  • Waterproof to 20 meters (66ft)

  • Can be used as an Optic USB based station for HOBO Pendant loggers, HOBO Water Level Loggers, and HOBO Water Temp Pro V2 Loggers
  • Allows for data readout under water while diving or snorkeling
  • Rugged waterproof construction
  • LEDs show offload and relaunch status

Optional Carrying Case

A hard-sided case with foam inserts that holds four HOBO Water Level Loggers and an Optic USB Base Station or Waterproof Shuttle.

25.4 x 20.3 x 7.9 cm 
(10" x 8" x 3.1")

Easy Wireline Deployment—no vent cables to worry about

Deluxe Water Level Logger and Barometric Pressure Kits

Each Kit Includes
>> Water Level Logger for Barometric Pressure (#U20-001-04)
>> Waterproof Base Station (#U-DTW-1)
>> Carrying Case (#U20-CASE-1) 
>> HOBOWare Pro Software (#BHW-PC)
and 1 additional Water Level Logger with various Ranges Available:
>>>> 0 to 13ft Range (#KIT-D-U20-04)
>>>> 0 to 30ft Range (#KIT-D-U20-01)
>>>> 0 to 100ft Range (#KIT-D-U20-02)

Deluxe Water Level Logger and Barometric Pressure Kits
Onset HOBO Deluxe Water Level Logger (0 to 30') and Barometric Pressure Kit KIT-D-U20-01
Onset HOBO Deluxe Water Level Logger (0 to 100') and Barometric Pressure Kit KIT-D-U20-02
Onset HOBO Deluxe Water Level Logger (0 to 13') and Barometric Pressure Kit KIT-D-U20-04


Starter Water Level Logger Kits
Onset HOBO Starter Water Level Logger (0 to 30') Kit KIT-S-U20-01
Onset HOBO Starter Water Level Logger (0 to 100') Kit KIT-S-U20-02
Onset HOBO Starter Water Level Logger (0 to 13') Kit KIT-S-U20-04

Starter Water Level Logger Kits
Each Kit Includes
>> Waterproof Base Station (#U-DTW-1)
>> HOBOWare Pro Software (#BHW-PC)
and 1 Water Level Logger with various Ranges Available:
>>>> 0 to 13ft Range (#KIT-S-U20-04)
>>>> 0 to 30ft Range (#KIT-S-U20-01)
>>>> 0 to 100ft Range (#KIT-S-U20-02)