The authors examine the nursing practice of disposing unaltered controlled substances into public water systems as an issue for nurses concerned with the environmental harm it can cause. A summary of the history of controlled substance management reveals inconsistencies in the interpretation of current regulations that have led to disposal policies that vary by institution, according to a benchmarking survey of regional hospitals. Much attention has been given to the phenomenon of conscientious objection in the context of patient care that conflicts with a nurse's moral integrity. Nurses who are compelled to dispose narcotics down drains may also face this struggle. The authors submit that this disposal method is based on a type of double effect logic where preventing diversion is viewed as a good effect of flushing unused controlled substances that outweighs any harm it may cause, though there is little evidence to support this conclusion. Consequently, the topic deserves further study so that nurse managers and administrators can support and offer alternatives to nurses who object to flushing drugs down the drain.