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Large septic systems can significantly impact the local hydrology over and immediately around their drainfields. Water table fluctuations under the drainfield of two large septic systems installed in sandy soils in the Coastal Plain region of North Carolina were monitored for two years. The actual wastewater application rates for the two systems were approximately 1.2 and 1.7 cm/d. Three wells, each equipped with a pressure transducer were installed in the middle of a subdrainfield and outside the drainfield area of each system to measure water table elevation continuously. Other wells were installed in and around each drainfield for manually measuring water table. Neutron probe access tubes and time domain reflectometry (TDR) rods were also installed at various locations within each subdrainfield to measure soil water content. Rainfall data from the nearest weather station for each site were used for the study. In general, no significant change in water level elevation was observed as a result of wastewater application to the drainfields. Additionally, the water levels measured hourly in all the wells indicated that water table elevation did not show any appreciable change during days with no rainfall. The water table, however, was raised after major rainfall events, as well as following a few consecutive rainy days in the area. This shows that changes in the water table elevation were only related to the rainfall and not to the wastewater application. Lack of significant ground water mounding under the two systems is perhaps due to the high hydraulic conductivity of the relatively thick unconfined aquifer under their drainfields.