Improving your ISO rating
A guide for Oregon fire chiefs, boards and city and county officials. ISO publishes how it scores fire protection, and many of the points come from things a department can document, train for or arrange with its neighbors.
How ISO scores a community
ISO's Fire Suppression Rating Schedule gives up to 105.5 points. Each class is a 10-point band: 90 points or more is Class 1, 80 to 89.99 is Class 2, and so on down to Class 10 below 10 points.
| Area | Points | What ISO looks at |
|---|---|---|
| Emergency communications | 10 | 9-1-1 reporting, telecommunicators' training and performance, dispatch circuits |
| Fire department | 50 | Engines and ladders, pump capacity, where stations are, personnel (15 points, the largest single item), training (9 points), operations |
| Water supply | 40 | Water available for fires, hydrants, and hydrant inspection and flow testing (7 points) |
| Community risk reduction | 5.5 extra | Fire code adoption and enforcement, public fire safety education, fire investigation |
If the fire department and water supply scores are far apart, ISO lowers the total ("divergence"), so a strong department with weak water, or the reverse, does not get full credit.
Sources: ISO, Fire Suppression Rating Schedule, items considered and scores and classes, checked November 1, 2026.
The minimums
To be rated better than Class 10, ISO requires a permanently organized department with a chief and a defined service area, at least four firefighters responding to every reported structure fire (one may be the chief), training at least 3 hours every 3 months, prompt alarm and dispatch, and at least one apparatus meeting NFPA 1901 kept out of the weather. Class 9 also needs a pumper, at least 500 gallons of water at every first-alarm structure fire, and records of who responded. Class 8 and better needs 250 gallons a minute for two hours, by hydrants or by a tender shuttle that starts within 5 minutes of the first engine's arrival.
Sources: ISO, minimum criteria to get a rating, Class 9 and Class 8 or better, checked November 1, 2026.
Where departments gain points
Staffing and volunteers
- Personnel is the largest single item. On-call and off-duty responders count for less than people on duty, to allow for the time it takes them to reach the fire, so more responders, and responders who arrive faster, earn more credit.
- Keep an up-to-date roster and records of how many members respond to each call. ISO checks them.
- Recruiting volunteers is one of the most direct ways a combination or volunteer department can protect its class. See how to recruit more volunteers and our free volunteer application forms.
Training, with records
- ISO's full-credit targets include 16 hours of company training per member per month, 18 hours a year at a training facility, 240 hours for each recruit in the first year, driver/operator training, officer certification with 12 hours of continuing education a year, a yearly hazmat session, and a yearly pre-fire plan inspection of commercial buildings.
- "When no records exist for training, there will be no credit." Log every hour.
Source: ISO, training.
Automatic aid
- Neighboring departments that are dispatched automatically on the first alarm to structure fires, 24 hours a day, every day, count toward your score. A written agreement is preferred, with common dispatch, radios and procedures. Help arranged call by call does not count the same way.
- In 2018, Mid-Columbia Fire & Rescue said a new automatic aid agreement with Mosier moved the area between the two "from a weak score of 9 to a strong score of 3."
Sources: ISO, automatic aid; The Dalles Chronicle, February 26, 2018.
Water supply, tenders and dry hydrants
- Where there are no hydrants, ISO credits dry hydrants, suction points, large-diameter hose relays and tender shuttles that can deliver 250 gallons a minute for two hours, starting within 5 minutes of the first engine's arrival, all year. ISO times your shuttle to set the credit, so practice and document it.
- Work with your water utility on yearly hydrant inspection, flow testing and marking (7 points).
- Homes 5 to 7 road miles from a station can get Class 10W instead of 10 when approved water is within 1,000 feet.
Sources: ISO, alternative water supplies and Class 10W.
Apparatus, testing and dispatch
- ISO sets no maximum age for apparatus; it credits pumps at their tested capacity. Keep pump, hose and aerial test records (NFPA 1911 and 1962).
- Ask your 9-1-1 center whether its dispatch circuits are monitored for faults, which ISO credits.
- Fire prevention, public education and fire investigation earn up to 5.5 extra points. Document them.
Sources: ISO, apparatus age, dispatch circuits.
ISO's free help
- A free review of your class and the changes that could improve it: your chief executive officer or another authorized official asks in writing.
- A free copy of the rating schedule for fire chiefs: call 1-800-444-4554, option 2.
- Mitigate, ISO's free online dashboard of your scores, maps and updates: sign up.
- Report changes, even small ones, such as a new station, apparatus or automatic aid agreement: ISO may re-survey.
- Call before large purchases. ISO asks departments to check how a big expense would affect the class first, and says it has not authorized any consultants to speak for it.
Contact: ISO, Community Hazard Mitigation, 1-800-444-4554, option 2, [email protected].
Sources: ISO, requesting more information, independent consultants, scheduling the survey; Verisk, PPC questions and answers, checked November 1, 2026.
Tell your community
- Post your class on your website, with which part of a split class applies by distance, as SW Polk and Hoodland do, and keep it on your FireDepartment.net listing with update your listing.
- Point residents to what the ISO rating means for their insurance.
- For budget hearings and board meetings, see fire protection, funding and insurance costs.
ISO says the main goal of improvements should be better service and public safety, "not the collateral benefits of a better PPC." This page summarizes ISO's published rules; ISO's own documents and your ISO representative are the final word.