Inevitably, the question will arise about whether accreditation will help lower the community's ISO rating. Data collected by Dennis Gage of ISO seems to indicate that it will. CFAI provides the following information:

The Insurance Services Office, Inc. (ISO) is the agency that collects data and analyzes the capability of community fire suppression services. This evaluation is based on criteria such as fire alarms (how well the department receives alarms and dispatches its resources), the number of engine companies (their distribution, etc.), and water supply (whether the community has a sufficient water supply, etc.). Essentially, ISO is classifying a community’s ability to fight fire.

The CFAI, on the other hand, provides a comprehensive system of fire and emergency service evaluation that can help local governments determine their risks and fire safety needs, evaluate the performance of the organizations involved, and provide a method for continuous improvement.

This presents a correlation between the ISO community assessment and the CAFI self-assessment. According to CPSE, in 2022 there were 290 accredited agencies. The remaining are military installations or are found in a state where there is an independent rating bureau. Of the 290 accredited agencies with an ISO classification, the following is a breakdown by classification:

Note that if you want to improve your ISO classification to a class five or better, accreditation is a good opportunity to do so. Conversations with ISO representatives indicate that it is possible that future versions of the ISO Fire Suppression Rating Schedule will provide some level of credit for accreditation.