With a 6-week-old baby, a home-based business and a job with a software company, it's not as though Minneapolis resident Mark Johnson wasn't busy.

But then he heard from a friend who expressed astonishment over getting socked with a potential 18 percent property tax increase. Johnson went through his own mail and got his own surprise.

His notice of proposed 2011 taxes informed him that he could pay 7.2 percent more on his duplex in the Linden Hills neighborhood. That's despite a 7.3 percent cut by the assessor in the property's estimated market value.

Johnson didn't shrug it off and move on. He took the lead in organizing a website and a City Hall rally scheduled for Monday at 5 p.m., so that residents upset by their proposed tax increase can sound off. Then they can go upstairs to the 6:05 p.m. meeting where the City Council will take testimony before adopting a 2011 budget and levy.

Johnson and his sympathizers have already had an effect downtown. It's not just the few dozen people who, like Johnson, showed up at a Nov. 18 session to tell council members what they thought of up to 20 percent increases in their home tax. Many others called or e-mailed their council members.

That helped to shrink the increase somewhat. The property tax notices that taxpayers like Johnson got were based on the city collecting 7.5 percent more money citywide next year. Because of shifts in value among property classes and among homes in different areas of the city, some homeowners faced double-digit percentage tax hikes.

But the recommended levy coming before the council Monday would collect 4.7 percent overall next year. Most of that will cover increased expenses for past pension commitments.

Johnson said he doesn't think the reduction will dampen interest in the rally. "I think a lot of people are wondering what 4.7 percent would mean on their property tax statement," Johnson said.

Johnson is the Senate District 60 Republican chair, and the rally will include some former Republican candidates for office, but he said the tax protest isn't partisan. In fact, one of the speakers will be former school board member Ann Berget, a DFLer.

Johnson doesn't come across as a ranter. He said he appreciates clean streets and other services the city provides. "I think a lot of people have been grumbling to themselves," he said of the increasing municipal tax burden, adding: "I think a lot of people have trust in government in Minneapolis."

Johnson said he and his wife bought their duplex in 2004. They intended to someday move to a single-family house and keep the duplex as an investment. But they now owe more on it than the assessor says it's worth.

When a previous tenant moved out to use her federal tax incentive to buy a house, it took Johnson three months to find a new tenant, and he had to lower the rent to do so. That makes it harder to pay a higher tax bill. He invites people to rally with him.

"Our silence would be their [the council's] stamp of approval," he said.

Steve Brandt • 612-673-4438