Flood Control in Arizona

Maricopa County Flood Control Agency is responsible for flood plain management, mapping, development permitting, and enforcement for unincorporated (non-city) areas of Maricopa County as well as several communities that lack resources to do so themselves. County Flood Control also builds capital improvement projects, such as levees, culverts, and other flood-control structures in the unincorporated ares and sometimes in communities it manages, where expenses are then shared. Plans for flood control structures must be approved and inspected by the Army Corps of Engineers. All efforts are geared to prevent flood damage at the 100-year flood level, or the level at which an area is expected to have a 1% chance of being flooded up to 1 foot in 100 years.

While the county maps the floodplain, FEMA (the Federal Emergency Management Agency) has the final say over the published maps. Ultimately, the maps are used by FEMA to produce the FIRM (National Flood Insurance Rate Map), which determine whether homes are located in a SFHA (Special Flood Hazard Area). Home owners located in an SFHA that have government-backed mortgages are required to purchase flood insurance and the FIRM is used to determine how much the insurance will cost. FIRM is a product of the National Flood Insurance Program, which is a federal program created to offer flood insurance since many private insurers do not cover flood damage.While those who have paid off their homes or have non-government-backed mortgages are technically not required to purchase flood insurance, it's still a good idea and private banks may still require the insurance.

County staff also spend time keeping current with the voluntary federal Community Ratings System program (CRS), which is a federal program that allows communities to earn discounts on flood insurance.  By meeting and exceeding flood prevention and control standards for properties, as outlined , such as by elevating houses, implementing public education programs, mapping floodplains, and other activities, insurance rate discounts can be obtained for property owners. Discounts range from between 5% to 45% for those in flood zones, based on the degree of participation in the program. Maricopa County is expecting to get a #4 CRS rating, conferring a 30% on flood insurance for property owners.