Sub-surface irrigation in turf has advantages over traditional sprinkler systems. Evapotranspiration is reduced and water applied below the root zone promotes deeper root growth. Auditing such applications requires measurement of root-zone soil moisture. Data was taken in 2008 and 2009 on a private lawn in northern California that had just been rebuilt to include both sub-surface drip and overhead spray irrigation systems. A portable wave reflectometer was used to take geo-referenced soil moisture readings in the top 5 inches of the root zone before and after scheduled irrigation events. Readings were taken in at 3 - 4 foot intervals. Photosynthetic light and soil moisture were logged at 1-hour intervals in sunny and shady areas of the property. Soil moisture distribution uniformity was computed. Soil moisture spatial variability was mapped using on-line software. Data showed that in the spring, soil moisture was driven by light. In the summer, root extraction by trees was a more important factor in locating dry areas of the lawn.