This paper presents long-term (six-year in duration) field monitoring results of moisture in six completely rehabilitated highway pavement sections on Interstate I-90 in Ashtabula county, Ohio. There were a total of six monitoring sections for six different drainable base materials used in construction. The Time Domain Reflectometery (TDR) was used to measure moisture contents in different pavement layers and cohesive subgrade soils (up to 1.829 m below the pavement surface). Statistical analysis was performed to exam the time history of moisture variations at different pavement layers as well as seasonal variations of moisture profile with depth. The comparative effectiveness of six different drainable base materials in alleviating excess moisture in the pavement system was also evaluated based on statistical analysis of moisture data.