This report addresses legislative questions concerning the DASA Treatment Expansion proposed in the 2005-2007 Governors' Budget. The report provides a range of estimates of the impact of substance abuse treatment on medical and nursing home costs for disabled or aged clients, under alternative modeling assumptions. Estimates from this report were ultimately used be legislative staff as the basis for medical and long-term care cost savings assumptions for the Division of Alcohol and Substance Abuse Treatment Expansion as funded in the 2005-07 Washington State Budget.