When the Alexandria City Council voted for a tax increase in its coming year’s budget last week, it removed a line that required the city set aside a portion of the tax revenue for its affordable housing and open space funds.

Whether the deletion was an inadvertent error is unclear. But the action has alarmed some council members and they promise to revisit it during their meeting Tuesday night.

The change wasn’t discovered until the council’s minutes were published and Vice Mayor Allison Silberberg raised an alarm. The DelRay Patch first reported the error.

Affordable housing is a major issue in this small northern Virginia city. More than 10,000 homes considered affordable have been lost in recent years as rents ratchet up. Open space also is at a premium as developers build on once-empty lots inside the Beltway.

Silberberg, who is in Dallas on family matters this week, said by phone Tuesday afternoon that there was no consensus during the council’s budget workshops that a majority of the council wanted to remove the money set aside for affordable housing (six-tenths of one cent per $100 of assessed value) and three-tenths of one percent on each $100 of assessed value). The property tax rate for fiscal year 2014 is $1.038 cents per $100 of assessed value, which means the owner of a home valued at $470,644 (the city’s average) will pay $4,885 in property taxes next year.

“The long-established affordable housing fund and open space fund has made an incredible difference in helping Alexandria keep its commitments,” Silberberg said. “It wasn’t an afterthought, it was a commitment. . .. If we want to make changes, okay, let’s have that discussion openly. Let’s not just add it in because this does not bode well for the democratic process.”

City manager Rashad Young said later Tuesday afternoon that the vote does not actually cut funds for the coming year because the money that would have been raised by the set-aside is already built into the fiscal 2014 budget. If the council decides it wants to return the set -aside, that can still be done, he said, and if it wants to fund affordable housing and open space another way, that can still be done at the June council meeting.

“This doesn’t reduce our commitment to affordable housing, it just changes how we fund it,” said council member Justin Wilson in a separate interview.

Alexandria used to set aside a penny of its tax rate for affordable housing and open space. That changed after the economic downturn of 2008, and now only six-tenths of a cent is set aside.

This spring, Silberberg had attempted to raise that number, as had council member John Taylor Chapman, but neither could muster enough votes. The budget process was a bit rushed; the council’s last discussion of what to add and what to delete to the budget came just minutes before the official vote. City staff rushed out of that meeting to prepare the final version of the budget that the council was due to pass within the hour.

Mayor William D. Euille (D) told the DelRay Patch that’s when the change occurred. He said the council would discuss the matter Tuesday.