Urban areas require intense water flows in order to operate. The analysis of the state of such water flows is better understood from metabolic studies that allow analyzing water flows entering and leaving the urban system. Objective: Quantify water flows of the Colombian Central-Western Metropolitan Area, determining the extent of its demands and the strictness of the city on water resources. Method: The material flow analysis was used as methodological tool to quantify the urban system inflows, intermediate flows and output flows. Results: In the area studied, 86% of the water is supplied by the Otun river as the main local source and the remaining 14% is supplied by external water sources. The water diverted annually for the urban supply of its 599.618 inhabitants consumption reached 31.2 MMC/year that is 113 l/person/day. Regarding outflows it is important to highlight that wastewater is discharged directly into water sources without any pre-treatment. The material balance determined a volumetric water flow for 2011 of 155.2 MCM/year that enters and leaves the metropolitan region. Conclusion: In the Central-Western Metropolitan Area water resource management follows a linear process (collection, distribution, consumption and discharges) generating untreated waste streams that are reintroduced into the ecosystem cycle. The demand and consumption of water have a decreasing trend in opposition to population growth, indicating better rational use of resources or an adaptation strategy to the public service cost.