ISO Rating Information

Public Protection Classification

During May 2011, the City of Denison was audited by our Insurance Services Office, Inc. (ISO) representative and received a Class 3 Public Protection Classification. This represents a 1 point improvement from our previous Class 4 rating.

The rating, established by ISO, evaluates the performance of municipal fire suppression capabilities. The city rating schedule consists of 3 main areas: receiving and handling of fire alarms, the Fire Department, and water distribution and supply. The ranking of these items leads to an overall public protection classification, which is 1 element used to determine fire insurance rates.


As of July 2016, the Denison Fire Department consists of 3 fire stations and 57 career firefighters, including the chief, assistant chief, fire marshal, and training officer. The shift firefighters work 24-hour shifts while the staff officers work from 7 am to 4 pm Monday through Friday. The staff officers are also on call during off hours for any major incident occurring within the city of Denison.

Fire Coverage

The Fire Department covers the 23 square miles within the city and 90 square miles of Grayson County. In the city, there are fire hydrants an average of 500 feet apart. Denison also has mutual aid agreements with multiple area fire agencies.
Because of the improvements made by the City of Denison over the past few years, citizens receive a higher level of fire protection and overall public safety.