HOBO U20-001-03 – 76 Metre (250′) Depth Water Level Data Logger

SKU: U20-001-03


The HOBO water level data logger features high accuracy at a great price and ease-of-use, with no cumbersome vent tubes or desiccants to maintain. This data logger is ideal for recording water levels and temperatures in shallow wells, streams, lakes and freshwater wetlands.

View how the HOBO Water Level Logger compares to the Competition.

  • Lightning protection – no long signal wires, and electronics are shielded in stainless steel housing for use in freshwater (see the Water Level logger sensor location drawing)
  • HOBOware Pro software provides easy conversion to accurate water level reading, fully compensated for barometric pressure (see demo) temperature, and water density.
  • Multiple-rate sampling (see demo) allows faster sampling at critical times such as when pumping starts or stops.
  • Available in 4 depth ranges
  • Ideal for use in wells, streams, lakes, wetlands and tidal areas
  • No-vent-tube design for easy reliable deployment
  • Available in stainless and titanium versions
  • Durable ceramic pressure sensor


The U20-001-03 and U20-001-03-TI Data Logger is for use in Outdoor and Underwater environments


The U20-001-03 and U20-001-03-TI Data Logger supports the following measurements :

Temperature, Barometric Pressure, Water Level

OPERATION RANGE 0 to 850 kPa (0 to 123.3 psia); approximately 0 to 76.5 m (0 to 251 ft) of water depth at sea level, or 0 to 79.5 m (0 to 262 ft) of water at 3,000 m (10,000 ft) of altitude
FACTORY CALIBRATED RANGE 69 to 850 kPa (10 to 123.3 psia), 0° to 40°C (32° to 104°F)
WATER LEVEL ACCURACY* Typical error – 0.05% FS, 3.8 cm (0.125 ft) water
MAXIMUM ERROR – 0.1% FS, 7.6 cm (0.25 ft) water
RAW PRESSURE ACCURACY** 0.3% FS, 2.55 kPa (0.37 psi) maximum error
RESOLUTION < 0.085 kPa (0.012 psi), 0.87 cm (0.028 ft) water
THERMAL RESPONSE TIME (90%)*** Approximately 10 minutes in water to achieve full temperature compensation of the pressure sensor
OPERATION RANGE -20° to 50°C (-4° to 122°F)
ACCURACY 0.37°C at 20°C (0.67°F at 68°F), see Plot A
RESOLUTION 0.1°C at 20°C (0.18°F at 68°F) (10-bit), see Plot A
RESPONSE TIME (90%) 3.5 minutes in water (typical)
STABILITY (DRIFT) 0.1°C (0.18°F) per year
REAL-TIME CLOCK ± 1 minute per month 0° to 50°C (32° to 122°F)
BATTERY 2/3 AA, 3.6 Volt lithium, factory-replaceable
BATTERY LIFE (TYPICAL USE) 5 years with 1 minute or greater logging interval
MEMORY (NON-VOLATILE) 64K bytes memory (approx. 21,700 pressure and temperature samples)
WEIGHT Approximately 210 g (7.4 oz)
DIMENSIONS 2.46 cm (0.97 inches) diameter, 15 cm (5.9 inches) length; mounting hole 6.3 mm (0.25 inches) diameter
WETTED MATERIALS Stainless Steel models: 316 stainless steel, Viton® o-rings, acetyl cap, ceramic sensor
Titanium models: Titanium, Viton o-rings, acetyl cap, ceramic sensor
SHOCK / DROP Logger is sensitive to shocks. Handle with care and avoid any impact. Always use proper packaging when shipping the logger.
LOGGING INTERVAL Fixed-rate or multiple logging intervals, with up to 8 user-defined logging intervals and durations; logging intervals from 1 second to 18 hours. Refer to HOBOware software manual.
LAUNCH MODES Immediate start and delayed start
OFFLOAD MODES Offload while logging; stop and offload
BATTERY INDICATION Battery voltage can be viewed in status screen and optionally logged in datafile. Low battery indication in datafile.
The CE Marking identifies this product as complying with all relevant directives in the European Union (EU).

* Water Level Accuracy: With accurate reference water level measurement and Barometric Compensation  Assistant data
** Raw Pressure Accuracy: Absolute pressure sensor accuracy includes all pressure drift, temperature, and hysteresis-induced errors
*** Thermal Response Time: Maximum error due to rapid thermal changes is approximately 0.5%