Many Northeastern US dairy farms have surplus nutrients because of imported feed. The surplus accumulates in the soil and might affect water quality. Excess phosphorus is most problematic and has caused algal blooms in the drinking water supplies for New York City (NYC). NYC provides funding for reducing P losses from farms to water. This study assessed the effectiveness of this program in controlling P accumulation in soils. Over 1200 field soil sample series at least six years long with sampling at three year intervals were analyzed. The results indicate increasing Morgan's P in initially low P soils that is counterbalanced by decreasing Morgan's P in initially higher P soils. The breakpoint is around 12 kg P/ha. Regression analysis found increased Morgan's P concentration with: corn frequency, higher recommended manure rate, and higher aluminum; and a negative effect of soil wetness. The soil status indicates that NYC watershed farmers have taken heed of nutrient management recommendations and supporting Best Management Practices.