Uri Monson, the district’s chief financial officer, noted that the budget is a best guess based on city and state projections, but that two bills soon coming up for hearings before City Council — one increasing the homestead exemption rate to $50,000 and another enacting a tax rate each year that would be “revenue neutral” — could alter the district’s finances considerably. If both are enacted, they would cost the district $42 million next year, and nearly $500 million over the next five years.