Potential water quality impacts associated with using bottom ash (BA) and composted dairy manure (CM) as a soil amendment were evaluated in this study. Two column studies were conducted to evaluate three blends of acidic BA and CM (BA:CM, v/v) namely, B1(ac) (95:5), B2(ac) (90:10), and B3(ac) (80:20) and three blends of alkaline BA and CM (BA:CM, v/v), namely, B1(al) (95:5), B2(al) (90:10), and B3(al) (80:20) under constant head water table conditions. Samples from standing water (top) and leachate (bottom) were collected at weekly intervals until day 49 to evaluate the effects of different blend ratios and elapsed time on standing water and leachate chemical and physical properties. A higher CM content in both acidic and alkaline blends resulted in higher leachate concentrations for solids and nutrients tested in this study. Alkaline blends had higher standing water and leachate nutrients concentration compared to acidic blends. After day 28, standing water total dissolved solids (TDS) concentrations for all acidic blends was below the USEPA drinking water standard however, TDS value for alkaline blend was always below the standard. Similar trends were also observed for NO3-N and phosphorus (P) concentrations for both blends. Based on these findings, it was concluded that acidic and alkaline blends B1(ac), B1(al), B2(ac) and B2(al) may be considered as a soil amendment material. (C) 2007 Elsevier Ltd. All rights reserved.