The HOBO U20L-01 is a low-cost, research-grade water level data logger for continuously measuring water level and temperature in a wide range of underwater environments. It features 0.1% measurement accuracy, a polypropylene housing for use in both fresh and salt water, and a non-vented design for convenient and hassle-free deployment.
Self-contained non-vented design enables easy deployment
Ideal for use in both fresh and saltwater environments, including wells, streams, lakes, wetlands, and tidal areas
Depths up to 30 feet
Durable ceramic pressure sensor withstands freezing
HOBOware Pro software provides easy conversion to accurate water level reading, fully compensated for barometric pressure (see demo), temperature, and water density
In what environment does this data logger operate?
This data logger operates in outdoor and underwater environments.
What measurements does this data logger support?
The U20L-01 data logger supports the following measurements: Absolute Pressure, Barometric Pressure, Temperature and Water Level
Pressure (Absolute) and Water Level Measurements U20L-01
0 to 207 kPa (0 to 30 psia); approximately 0 to 9 m (0 to 30 ft) of water depth at sea level, or 0 to 12 m (0 to 40 ft) of water at 3,000 m (10,000 ft) of altitude
Factory Calibrated Range
69 to 207 kPa (10 to 30 psia), 0° to 40°C (32° to 104°F)
310 kPa (45 psia) or 18 m (60 ft) depth
Water Level Accuracy*
Typical error: ±0.1% FS, 1.0 cm (0.03 ft) water
Raw Pressure Accuracy**
±0.3% FS, 0.62 kPa (0.09 psi) maximum error
<0.02 kPa (0.003 psi), 0.21 cm (0.007 ft) water
Pressure Response Time (90%)***
<1 second at a stable temperature; measurement accuracy also depends on temperature response time
-20° to 50°C (-4° to 122°F)
±0.44°C from 0° to 50°C (±0.79°F from 32° to 122°F), see Plot A in manual
0.10°C at 25°C (0.18°F at 77°F), see Plot A in manual
Response Time (90%)
10 minutes in water (typical)
0.1°C (0.18°F) per year
±1 minute per month 0° to 50°C (32° to 122°F)
2/3 AA, 3.6 Volt lithium, factory-replaceable
Battery Life (Typical Use)
5 years with 1 minute or greater logging interval
64K bytes memory (approx. 21,700 pressure and temperature samples)
Approximately 154 g (5.43 oz) in air Approximately 53.9 g (1.9 oz) in fresh water
3.18 cm (1.25 inches) diameter, 15.24 cm (6.0 inches) length; mounting hole 6.3 mm (0.25 inches) diameter
Polypropylene housing and lanyard; Viton and Buna-N O-rings; ceramic sensor in acetyl end cap; stainless steel screws suitable for saltwater
Fixed-rate or multiple logging intervals, with up to 8 user-defined logging intervals and durations; logging intervals from 1 second to 18 hours.
Immediate start and delayed start
Offload while logging; stop and offload
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).