CBS (CHICAGO)–Some property owners on Chicago’s north side are experiencing sticker shock after seeing double-digit property tax increases this year.

An attractive housing market for sellers on the north side has led to the increase, according to Cook County Assessor’s Office spokesperson Tom Shaer.

“Previous assessed values were artificially low because we were coming off the worst housing crash in history,” Shaer said.

Condo owner Margot Wang told CBS 2’s Jim Williams she couldn’t believe her eyes when she saw the new assessed value of her one-bedroom unit in the Uptown neighborhood.

“Fifty percent is crazy—it’s the highest one I’ve ever received,” Wang said.

The increases are affecting homeowners all over Lake View Township.

Andrea Raila, a former candidate for Cook County Assessor, described the increases as “astronomical.” The average increase is about 32 percent, she said.

“We’ve had seniors tell us how the property tax is above their mortgage payments,” Raila said.

Property owners who believe their tax bills are inaccurate can file an appeal through the Assessor’s office.

Homeowner Margot Wang doesn’t have plans to move anytime soon, and said the hot seller’s market is no consolation for her high tax bill.

“It’s a high increase that I don’t think we can keep up with, so this is crazy,” Wang said.

A denied appeal means property owners will owe the full amount due.