This product contains time-series data for groundwater level altitudes in bedrock boreholes and meteorological information from a site administered by the U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS). The site, referred to as the Masser Groundwater Recharge Site, is located in the Valley and Ridge Physiographic Province of eastern-central Pennsylvania, USA, approximately 40 kilometers (km) north of Harrisburg, Pennsylvania, USA. The period of record for the time-series data included in this product is from February 1, 1999 to December 31, 1999, which corresponds to an investigation of time-varying groundwater recharge from precipitation events. The groundwater level altitudes in bedrock boreholes and precipitation from a meteorological station at the USDA, ARS site are collected and reported at 30-minute intervals. The average, minimum, and maximum daily air temperatures at the site are acquired for the period of record from gridded data provided by the National Oceanic and Atmospheric Administration (NOAA). Time-series groundwater level altitudes for U.S. Geological Survey (USGS) well (site number: 404239076362001) is also included (U.S. Geological Survey, National Water Information System).