Knowing the groundwater levels in observation and production wells is the basis for almost all assessments of groundwater hydraulics. Traditionally, water levels are determined manually with dip meters or indirectly via pressure sensors below the water table. The methods have proven to be robust over years, but are often not applicable, because either the gadgets are (1) not available in the area, (2) too costly or (3) not applied adequately. Due to these obstacles, many well water levels are still not monitored appropriately until today and projects like the Global Groundwater Monitoring Network (GGMN) by IGRAC (2025) show large gaps in non-OECD countries.

The smartphone app “Groundwater Global” allows everybody with access to an observation well the determination of groundwater levels by using the phone’s speaker and microphone. The app is available for iOS and Android and offers good accuracy for basically all smartphones on the market, when the well setup is suitable. The suitability of a well is mainly determined by the well diameter, the type of casing and the filter screen. The app is complemented by a database system to store the measurement results and connect them to specific locations.

When factors like air temperature are considered, the well water level can be determined with an accuracy of ±2 cm down to a depth of 25 m below well head, independently from the phone type. This was confirmed in a laboratory study with 18 different phone types for different well pipe lengths and will be evaluated further in an upcoming field study.

The app allows groundwater monitoring even under difficult circumstances and can be considered a promising tool to assess water levels at single wells as well as to improve the coverage of projects on larger scale such as the GGMN by IGRAC (2025).

References:

IGRAC (2025) - The Global Groundwater Monitoring Network (GGMN). Retrieved from https://ggmn.un-igrac.org/ (Accessed [30-10-2025]). DOI: https://doi.org/10.58154/6Z0Y-DA34