An extensive literature survey revealed there have been no in-depth studies of the quantity of water entering Orlando area drainage wells. Previous values ranging from 30 to 85 MGD were based on water supply withdrawal information or gross drainage area estimates. This paper presents a detailed study of the quantity of water entering 208 drainage wells in the Orlando Ubran Stormwater Management Manual (OUSWMM) area. Extrapolation of results to the remaining wells in Orange County is discussed briefly. Field experiments on one 20 in drainage well yielded a mathematical relationship that was reasonable for estimating acceptance rates for drainage wells of all sizes. One hundred seventeen drainage sub-basins have been identified in the 54,000 acre OUSWMM area. Seventy-four of these sub-basins contain or contribute flow to one or more of the 208 drainage wells. Weighted mean daily runoff in the 74 sub-basins was estimated between 39.1 and 53.4 MGD. Storage effects reduce this to 17 to 31 MGD, which is the maximum quantity of runoff available to the drainage wells. Other effects could reduce this more. A well hydraulics estimate of the inflow quantity was 18 to 47 MGD. This agreed reasonable well with the estimate of the available runoff. Deviation between the two could be due to the limited amount of data on heads on the well.