This manual brings into one volume, information valuable as a reference source for those persons actively engaged in or planning groundwater monitoring programs at solid waste disposal facilities. It was completed prior to passage of the Resource Conservation and Recovery Act of 1976, which contains major provisions to move the country more rapidly toward environmentally safe solid waste disposal practices. The implications for monitoring activities are clearly great, and this manual should serve as a particularly useful tool as State solid waste agencies proceed to strengthen their land protection programs. The manual is primarily addressed to the supervisory personnel of solid waste regulatory agencies, although its contents can be readily used by engineers in the field.