Insurance Service Office (ISO) Rating

Learn More


The Northwest Fire District proudly maintains a Class1/1Y Public Protection Classification (PPC) rating issued by the Insurance Service Office (ISO), which places the District’s fire protection community in the top 1% in the country. The enhanced score went into effect on July 01, 2019 and works to ensure lower insurance costs for property owners within much of the Town of Marana and areas of unincorporated Pima County northwest of Tucson served by the Northwest Fire District.

Out of 39,378 fire departments/districts assessed by ISO, Northwest Fire District is one of 393 fire agencies in the United States to receive an ISO Class 1 rating.

ISO collects and evaluates information on municipal fire-protection efforts in communities throughout the United States. ISO’s Fire Suppression Rating Schedule (FSRS), evaluates four primary categories of fire suppression — fire department, emergency communications, water supply, and community risk reduction. After an analysis, communities are assigned a Public Protection Classification (PPC) from 1 to 10. Class 1 generally represents superior property fire protection, and Class 10 indicates that the area’s fire suppression program doesn’t meet ISO’s minimum criteria.

The PPC program from Verisk Analytics’ Insurance Service Office provides an objective, countrywide standard that helps secure lower fire insurance premiums for communities with better public protection.

The chart below shows the distribution of PPC Ratings for fire protection districts nationwide.

PPC Grade Distribution Chart
2 / 2Y

ISO Rating Letter

How Does ISO Rating Affect District Residents?

In addition to showing district boundaries, stations and facilities, the Interactive Map allows you to enter an address and verify if it is in the Northwest Fire District.


Upgrading the community’s fire prevention and suppression capabilities, specifically in the categories of dispatch, water supply, and fire suppression, helped the District achieve the Class 1 rating, as continued training and improvements help maintain the rating. In short, better prevention efforts and response capabilities and lower insurance premiums.

The District’s ISO rating is 1/1y. The first number (1) refers to the classifications of properties within 5 road miles of a fire station and 1,000 feet of hydrant. The second number (1y) refers to properties within 5 road miles of a fire station but beyond 1,000 feet of a hydrant.
For properties that fit into the second classification, NWFD utilizes water tenders carrying close to 3,000 gallons of water and/or may deploy water shuttle operations requiring multiple water tenders. Our firefighters train hard to maintain the rating and achieve the standards required by ISO.

ISO Public Protection Program

For more information regarding the ISO Public Protection Program, visit:


The files available on this page are in PDF format. If you are having trouble viewing them, click the button below to download Adobe Reader.