As Arizona enters its fifteenth year of drought and Lake Mead hits historic lows, water management and policy planning will become increasingly important to ensure future water security in the Southwestern region of the United States. This thesis compares water demand trends and policies at the municipal level in Phoenix and Tucson, Arizona over the time period from 1980-2010. By analyzing gallons per capita per day (GPCD) trends for each city in the context of population growth, drought, and major state and local policies over the twenty year period, reasons for declines in per capita water demand were explored. Despite differences in their available water sources and political cultures, both the City of Phoenix and the City of Tucson have successfully reduced their per capita water consumption levels between 1980 and 2010. However, this study suggests that each city's measured success at reducing GPCD has been more a result of external events (supply augmentation, drought, and differing development trends) rather than conservation and demand reduction regulations adopted under the auspices of the Groundwater Management Act.