Records water level and temperature up to 13-ft depths in wells, streams, lakes and freshwater wetlands. With its narrow range, this logger provides the best accuracy in shallow waters. A great value and easy deployment with no cumbersome vent tubes or desiccants to maintain. For saltwater deployments, such as brackish wetlands and tidal areas, see HOBO U20 Water Level Titanium.
|Pressure and Water Level Measurements U20-001-04 and U20-001-04-Ti|
Factory Calibrated Range
Water Level Accuracy*
Raw Pressure Accuracy**
Pressure Response Time (90%)***
0 to 145 kPa (0 to 21 psia); approximately 0 to 4 m (0 to 13 ft) of water depth at sea level
69 to 145 kPa (10 to 21 psia), 0° to 40°C (32° to 104°F)
310 kPa (45 psia) or 18 m (60 ft) depth
Typical error: ±0.075% FS, 0.3 cm (0.01 ft) water. Maximum error: ±0.15% FS, 0.6 cm (0.02 ft) water
±0.3% FS, 0.43 kPa (0.063 psi) maximum error
<0.014 kPa (0.002 psi), 0.14 cm (0.005 ft) water
<1 second; measurement accuracy also depends on temperature response time
|Temperature Measurements (All Models)|
|Range||-20° to 50°C (-4° to 122°F)|
|Accuracy||±0.44°C from 0° to 50°C (±0.79°F from 32° to 122°F), see Plot A in manual|
|Resolution||0.10°C at 25°C (0.18°F at 77°F), see Plot A in manual|
|Response Time||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|
5 years with 1 minute or greater logging interval
64K bytes memory (approx. 21,700 pressure and temperature samples)
Stainless steel models: 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||316 stainless steel, Viton® o-rings, acetyl cap, ceramic sensor|
|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 the 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.|
Requires HOBOware Pro software and either a U-DTW-1 Waterproof Shuttle or the Base-U-4 Optic USB Base Station for configuration and data offload.
* Water Level Accuracy: With accurate reference water level measurement, known water density, accurate Barometric Compensation Assistant data, and a stable temperature environment.
** Raw Pressure Accuracy: Absolute pressure sensor accuracy includes all sensor drift, temperature, and hysteresis-induced errors.
*** Changes in Temperature: Allow 10 minutes in water to achieve full temperature compensation of the pressure sensor. Maximum error due to rapid thermal changes is approximately 0.5%.