Failure of leachate collection systems is expected to be a problem in the operation of hazardous waste disposal facilities, just as failure of drainage systems has been a problem at agricultural sites. The principal failure mechanisms include sedimentation, clogging by biological, chemical and biochemical materials, and mechanisms which do not involve clogging including pipe deterioration, pipe displacement and exceeding design capacity. Operating experience with leachate collection systems indicates that all of the failure mechanisms have occured in the field, although experience with chemical and biochemical precipitation is limited. In a survey of 22 waste disposal facilities which had leachate collection system problems, 14 experienced problems attributable to errors in design, construction or operation. The remaining 8 experienced problems that could likely have been avoided through system maintenance. Designing to avoid failure includes careful pipe location, fallback systems or redundancy, allowing for maintenance requirements and addressing specific failure mechanisms. Construction must involve adequate quality assurance and may require special construction techniques. Operation of leachate collection systems to avoid failure includes regular inspection and system maintenance to find and address problems before they become too serious.