The reassessment of part or all of the jet-ravaged 41st, 45th, 38th, 39th, 33rd and 40th wards in Jefferson Township will be based only on sales market activity during the 2012, 2013 and 2014 calendar years.

The new flight paths that have bombarded areas east and west of O’Hare debuted on Oct. 17, 2013 — or less than half of the assessment period. Plus, officials with the office of Cook County Assessor Joseph Berrios said, markets take time to reflect trends.

The good news for Jefferson Township homeowners is that the Cook County assessor’s office will take the unusual step of “revisiting” affected areas in that township next year, after more market data and the results of a comprehensive review of jet noise implications are available, officials said. Normally, reassessments are done every three years.

“We recognize that the calendar is not Jefferson Township’s fault,” said Tom Shaer, deputy assessor for communications. “We therefore are giving them a special revisiting next year to provide a more complete period of study. Assessor Berrios doesn’t think [homeowners] should have to wait another three years.”

The reassessments being mailed Thursday and Friday will be reflected in tax bills arriving next August and due around Labor Day 2016.

The second look at Jefferson Township will be done in the same year that homes in other O’Hare-impacted areas of Norwood Park, Leyden and Maine townships are up for triennial reassessment.

By next year, Cook County officials will have overlaid a “noise contour” depicting the most heavily affected areas over each township, reviewed jet noise complaint data, read national and Canadian airport studies and examined at least 25 market variables to determine if jet noise is playing a role in home values, officials said.

West of O’Hare, in DuPage County, reassessment notices are due out in September for Addison Township areas heavily affected by the new flight paths. That includes Bensenville, Wood Dale and Itasca.

Addison Township Assessor Chris Kain said Wednesday it was too early to attribute any market impact directly to O’Hare flight changes because some of that area also was hit by extended construction on Irving Park Road. But Kain said he could clearly see that areas closest to O’Hare have yet to recover from the 2008 market collapse, unlike other areas of the township.

Assessments are expected to decline in areas closest to the airport, Kain said, and that includes some Bensenville homes on a street called “Hillside,” near the end of an O’Hare runway. Some Hillside homeowners have begged Chicago officials to “relocate” them and put them out of their misery.

Those who think their assessed valuation is too high can appeal, but their appeal must be tied to market activity, based on indicators such as days on the market, number of price drops and sales price, Kain said.

“I’m personally aware [of the situation] and I’ve tried to get as accurate a value in the township and for those closest to O’Hare as possible,” Kain said. “I’ve seen the planes, I’ve heard the planes, I’m in the field. I’m aware of the planes. It’s definitely a quality of life issue.”