Insurance Service Office (ISO)

ISO stands for “Insurance Services Office.” ISO rates municipalities with their capacity to handle a fire, and to minimize its damage to property.

What This Means for You


Every 15 years, ISO rates geographical areas by 3 areas and assigns that area a number from 1-10, 1 being the best rating. ISO then turns this information over to insurance companies. Insurance companies use this information to determine statistically the amount of damage a fire will do before being brought under control. ISO rates an area by the communications or 911 system, the water supply (including fire hydrants), and lastly the fire department. The 911 system makes up 10% of this rating, the water supply 40% and the capabilities of the fire department 50%.

The citizens of Fairmont benefit from an ISO rating of 2. This means that fire insurance in the city limits is considerably less than areas with higher ISO ratings (example: those that live in areas covered by volunteer fire departments are likely a class 8 and would pay twice as much for homeowners insurance).

ISO is due to re-evaluate in 2021