Product Code: U20L-04 The HOBO U20L-04 Water Level Data Logger is a compact, rugged data logger designed for long-term monitoring of water level and temperature in freshwater environments. The logger uses a vented pressure sensor to measure water pressure while automatically compensating for changes in atmospheric pressure. The U20L-04 is suitable for groundwater monitoring, stream and lake studies, hydrology, watershed research, environmental monitoring and water-resource management. Its compact design allows it to be installed in monitoring wells, stilling wells and other confined locations. The U20L-04 has a 0–4.4 m (0–14.7 ft) water-level measurement range, with a 0.05% FS accuracy. It can record measurements at user-selectable intervals and stores up to 21,200 measurements. The logger features a durable, corrosion-resistant housing and is designed for extended deployment in freshwater applications. Measures water level and temperature 4.4 m (14.7 ft) water-level range Vented pressure-sensor design Automatic atmospheric-pressure compensation Compact design for wells and other confined installations Stores up to 21,200 measurements User-selectable logging intervals Suitable for long-term environmental monitoring Rugged, corrosion-resistant housing Ideal for groundwater, surface-water and hydrological studies Pressure (Absolute) and Water Level Measurements Operation Range 0 to 145 kPa (0 to 21 psia); approximately 0 to 4 m (0 to 13 ft) of water depth at sea level, or 0 to 7 m (0 to 23 ft) of water at 3,000 m (10,000 ft) of altitude Factory Calibrated Range 69 to 145 kPa (10 to 21 psia), 0° to 40°C (32° to 104°F) Burst Pressure 310 kPa (45 psia) or 18 m (60 ft) depth Water Level Accuracy* Typical error: ±0.1% FS, 0.4 cm (0.013 ft) waterMaximum error: ±0.2% FS, 0.8 cm (0.026 ft) water Raw Pressure Accuracy** ±0.3% FS, 0.43 kPa (0.063 psi) maximum error Resolution
