The Arlington County Board did not raise property tax rates Saturday in adopting its $1.276 billion budget for the coming fiscal year, but higher assessments and fees mean the average tax bill will increase 3.5 percent.

The board voted unanimously to keep the property tax rate at $1.006 per $100 of assessed value (including the storm water tax). Adding in the fee hikes, the average homeowner will see their tax bill increase by $296, to $8,742.

Katie Cristol (D), chair of the county board, called the budget “a sustainably progressive investment in our values.”

While the rise in Arlington property values has fueled spending growth for years, significantly higher costs for schools, Metro and debt service are outpacing that growth, she noted.

For the fiscal year that begins July 1, the schools budget will increase by $10.6 million, to $500.8 million, including $2.5 million that the board cut from the renovation of the county’s government center. Metro funding will increase 3 percent, to $73.1 million. The county’s affordable-housing investment fund, which loans money to nonprofit developers who create low-cost housing, was increased to $14.3 million.

“We can’t grow per-pupil annual increases in the transfer to schools when the number of pupils are growing at the rates we’ve seen,” Cristol wrote on Facebook. “We can’t increase the general fund contributions to affordable housing investment fast enough to support every compelling affordable housing project, when projects a decade ago required $5 or $6 million in gap financing and current projects need $20 million. . . . We have to find a way to show our commitment through better measuring outcomes and impacts, not just through the input of dollars spent.”

To slow the rising cost of government and close a $20 million budget gap, the board made $8.4 million in cuts and increased fees by $6.6 million. Utility taxes are increasing by 5 percent for commercial users and by $3 per month for residential users. Household solid waste fees will rise $2 to $316.16 per year. Metered parking will cost a quarter more per hour and be enforced until 8 p.m.; fines also will increase to $40. A variety of other fees charged for services also will increase.

The ever-more-competitive race between counties and cities to find, train and keep police officers and firefighters caused the board to add $1.595 million in public safety compensation beyond the pay raises of 2.5 percent to 4 percent that County Manager Mark Schwartz proposed in February. Other county employees are eligible for 3.25 percent merit-based raises.