The purpose of this paper is to clarify the changes in the maintenance of irrigation and drainage facilities caused by structural changes in agriculture and a weakened sense of community in a hilly and mountainous area. The study was conducted at K district in Iga city, Mie prefecture. The main findings are as follows: (1) the irrigation associations have lost their function of water management and facility maintenance, (2) the maintenance workload and cost per farmer has become heavier than the 1970s because of the decrease in farmers and the difficulty of mechanization of the maintenance work. We also suggested the possibility that non-farmers can participate in the maintenance work when it is for landscape conservation, flood prevention, or it is combined with a local customary event.