San Diego Hydrogeology

Summary of transducer accuracy

Required Accuracy

Systems of pressure transducers, data loggers, cables and other supporting equipment used for sensing and recording water levels in wells should be sufficiently accurate to meet the needs of most ground-water projects of the USGS. The following have been suggested as standards: a water-level sensing and recording system should be capable of performing within a measurement error of + or – 0.01 ft. for most water-level measurement applications. For the case of large changes in water level (for example, during aquifer tests), this measurement error may not be achievable, and an accuracy of 0.1 percent of the expected range in water-level fluctuation is acceptable. Where the depth to water is greater than 100 ft, an accuracy of 0.01 percent of the estimated depth to water is generally acceptable. In summary, the measurement error and accuracy standard for most situations are 0.01 ft, 0.1 percent of range in water-level fluctuation, or 0.01 percent of depth to water above or below a measuring point, whichever is least restrictive.


Project Chief: Wes Danskin
Phone: 619-225-6132

Welcome to the United States Geological Survey (USGS) San Diego Hydrogeology project website, which provides geologic and hydrologic information for the transboundary San Diego–Tijuana area, USA and Mexico. This website provides background information about the project; a variety of news items; a large amount of data, in particular for USGS multiple-depth, monitoring-well sites; geologic and hydrologic models; and additional resources including photos, illustrations, and references. Last updated: April 2016

Some additional data may be available from the USGS database National Water Information System (NWIS).

Questions about San Diego Hydrogeology? Please contact Wes Danskin (email: or send a letter). 619.225.6132