The literature on ‘high reliability organizations’ demonstrates how central reliability is to organizing in certain highly demanding settings. In more mundane settings, however, where there may not be a dominant type of catastrophic failure, the meaning attributed to reliability is less likely to be unambiguous and consensual. It is more likely to be explicitly relational: a quality of the relationship between an entity that is being relied on and an entity that is relying on it. This draws attention to the importance of the relying process in contributing to how a system performs and whether it meets expectations. A field study was carried out in a highway construction and maintenance organization to analyse the various understandings of reliability that organizational members had in different contexts. It found that there were multiple understandings – involving a capacity not only to achieve particular outcomes but also comply with norms, fit behaviour to situations, and communicate about what could and could not be achieved. It also found that reliability problems were not solved in some simple sense. Instead they were transformed into other reliability problems that then had to be managed by further effort or by other organizations. We suggest that recognizing the multiple meanings of reliability, the importance of relying, and the way in which reliability problems are transformed from one form to another all have important practical implications.