Otter estimates $2.98 billion in tax revenue will flow into Idaho in the 2015 fiscal year, which starts in July. That's 6.4 percent more than this year.
The 18-person Joint Economic Outlook and Revenue Assessment Committee agreed with the projection in a unanimous vote Thursday.
Aligning with the governor means the committee largely agrees the state will have enough money to boost the 2015 budget by 3.7 percent to $2.9 billion while still socking away more than $40 million in savings, as Otter recommended earlier this week. However, lawmakers aren't bound by the governor's spending plan and can make their own changes over the coming three months.
Rep. Grant Burgoyne said although his final projection wasn't quite as optimistic as Otter's, he was still comfortable that the amount was reasonable.
"I'm not in a position to say that my number is better than the governor's," said Burgoyne, D-Boise.
The committee will present its recommendation to the Joint Finance-Appropriations Committee, which can take the figure under advisement but won't be bound the use it as its budget compass.
Otter's chief economist, Derek Santos, said his conclusion was based on optimism that Idaho continues to pull out of the recession. The jobless rate is dropping, the housing market is bouncing back, and revenue from sales, individual and corporate taxes is edging back toward pre-recession levels of 2007.
"I don't expect us returning to the bubble peak we had in the middle of the decade, but I do think we'll recover from the lows we hit in 2011," Santos said.
Sen. John Goedde, R-Coeur d'Alene, pointed out the difference between the committee's numbers and the governor's was a slim $50 million.
The lawmakers' median tax revenue projection for 2015 was about $2.93 billion. The difference was insignificant when viewed as part of a nearly $6 billion two-year budget, Goedde argued.
If the budget committee accepts the projection, it could strengthen Otter's bargaining position in backing projects he promoted during in his State of the State speech Monday, including giving an additional $37.4 million to public education, $15 million to buying water rights and developing enormous new dam projects, and chipping in $2 million to kill problem wolves that eat too many sheep, cows or elk.
Even so, legislators will be free to back their own budget proposals, including possible tax relief or as some members of the budget committee have suggested chipping in additional funding for state government worker pay.