Dairy and beef operations in the Okeechobee watershed and across the nation are receiving attention as a result of their contribution of excessive P to surficial water bodies. Numerous efforts are being made to support the agricultural industry and reduce P losses from the soil. One such effort involves the addition of water treatment residuals (WTRs) to the soil. Prior research has shown Al-WTRs are capable of binding P and therefore preventing P loss through runoff and leaching. Questions still remain regarding the influence of a perched watertable on P retention. The objective of this research was to evaluate the effectiveness of an Al-WTR applied at 2.5% by weight, on a manure-impacted soil from a dairy sprayfield with a perched watertable using a rainfall simulator. Soil samples from a field site were removed incrementally; 0-10cm and 10-20cm and repacked in boxes (100cm x 28cm). After rainfall simulation to produce runoff, the watertable was held at the surface for 24 hrs. Subsequently, the watertable was lowered and held at a depth of 10cm for 21 days. Losses of water soluble P (WSP) and total P (TP) in surface runoff and subsurface drainage will be presented for several rainfall simulation events.