What an Idaho Overlap Actually Costs
Program and regulatory figures verified September 25, 2026. Details change; confirm your scenario with us.
Work the three numbers in order, and start with the one most people get wrong: the departing payment after the exemption comes off.
Step one: the departing PITIA, unexempt
Principal, interest, taxes, insurance and any association dues on the home you are leaving. The trap is taxes. Your current bill reflects the homeowner's exemption, and you lose that on this property once you move out.
Take a $400,000 Idaho home as an illustration. With the exemption it is taxed on $275,000, because the flat $125,000 applies above the $250,000 crossover. Without it, on the full $400,000. Whatever your county's levy produces on that $125,000 difference is a monthly number you need inside the PITIA above.
Your county assessor administers the exemption and levy rates vary by taxing district, so get the figure from them rather than estimating here.
Step two: the rental offset
Under Fannie Mae B3-3.8-05, take monthly gross market rent, multiply by 75%, subtract the departing PITIA from step one.
- Positive: the departing residence's payment is offset. It stops counting against you, and nothing more.
- Negative: the shortfall is added to your debt-to-income ratio.
Step one feeds step two, and in Idaho it feeds it unfavourably: the exemption loss raises the PITIA you are subtracting, which makes a positive result harder to reach.
Step three: reserves
With less than 12 months of property management experience, six months of the vacated home's PITIA, in addition to reserves required for multiple financed properties.
And the ceiling
Check the county limit before any of this. Idaho's 2026 one-unit conforming limit is $832,750 in 43 of 44 counties and $1,249,125 in Teton County. Above the applicable limit you are on investor guidelines instead of the rules above. See the jumbo page.
Structures on the structures page, the exemption on the exemption page, rent rules on the Form 1007 page.
Frequently asked questions
How do I estimate what Idaho's homeowner's exemption is worth on my home?
For any home above $250,000 of value it is a flat $125,000 reduction in taxable value, under Idaho Code 63-602G(1). On a $400,000 home that is the difference between a $275,000 and a $400,000 taxable base. Your county applies its own levy to that difference, so ask the assessor for the dollar figure.
Should I use my current tax bill for the departing home?
No. Your current bill reflects the exemption, and you lose it on that property once it stops being owner-occupied under Idaho Code 63-602G(2)(a). Estimate the departing PITIA with the unexempt tax figure, because that is the payment underwriting will test.
What reserves should I plan for on an Idaho move-up?
For a rental conversion with less than 12 months of property management experience, six months of the vacated property's PITIA, plus any reserves required for multiple financed properties. Bridge structures tier reserves against local marketing time instead.
Mike Certo · NMLS #260555 · Cornerstone First Mortgage NMLS #173855 · Equal Housing Lender. Educational content about financing, not a loan commitment and not legal, tax, or real estate advice. Idaho's homeowner's exemption is administered county by county under Idaho Code 63-602G and 63-703, and eligibility depends on your facts; your county assessor, your CPA or an Idaho attorney, and your real estate agent each handle their own part. Loans are subject to borrower and property qualification.