Many irrigation systems in the dry zone of Sri Lanka have water shortage problems. In spite of the fact that water shortage is a problem, water consumption is very high during land preparation which takes prolonged periods of time. This paper analyzes the impact of institutional interventions on efficient water management, especially during the land preparation period, based on research conducted in Huruluwewa, Rajangana, Nuwarawewa and Minneriya irrigation schemes in maha season (wet season which is from October to mid January) 2001/2002. It provides a comprehensive understanding of the factors behind prolonged periods of land preparation so that system managers and farmer communities can develop appropriate interventions to reduce water consumption during this period.