Aquifer recharge rates are important for understanding hydrological patterns and assessing the sustainability of groundwater pumping rates. Uncertainty in recharge rates is high due to their invisible underground nature and the uncertainty in other water budget components. Aquifer hydraulic heads respond to changes in pumping rates in addition to short- and long-term climatic patterns, making it difficult to estimate recharge or isolate a particular factor as causal for water level changes. In this work, a vadose zone water budget was employed to approximate recharge for the 80 sq. km Alder Creek watershed in southern Ontario, which is important for local water supply. The water budget solved for annual recharge plus vadose zone storage change as the difference between precipitation and the sum of vadose zone actual evapotranspiration and overland flow. Historical precipitation, streamflow, and climatic data were used with several analytical tools. Potential evapotranspiration (PET) was estimated via the Penman-Monteith method. The Budyko curve was used to estimate average actual evapotranspiration as a fraction of average precipitation for the entire watershed based on PET. Finally, the PART hydrograph separation method was used to estimate overland flow by estimating groundwater baseflow as a fraction of total streamflow. Multi-year groundwater hydraulic head levels from local wells were used to assess estimated trends. The results appear to agree with available well data, and lag times between maxima and minima in precipitation and aquifer water levels can be derived. The method can assist water managers as a predictive tool for aquifer level trends.