Different aspects related to rainwater demand and supplies for non-potable uses at Sao Paulo International Airport, in Guarulhos, Brazil were analyzed. For this, it was investigated different demand stratum and defined the intended uses. Subsequently, the supply and reservoir volume were evaluated. The daily balance for one year was evaluated for distinct scenarios, considering different arbitrated volumes and demands. The results indicated that rainwater could supply 44% of the airport's cold water central (air conditioning system) demand. Considering the maximum daily demand identified (118 m(3).dia(-1)) and the higher water cost scenario, reservoir volumes from 500 to 3,732 m(3) presented efficiencies close to 60% and payback between 3.5 and 7.5 years. For the lower water cost scenario, volumes from 500 to 1,700 m(3) showed payback between 7 and 10 years, also considering the maximum daily demand.