House flipping in Idaho: 70% rule, holding costs, and what kills deals

Flipping in Idaho: the 70% rule applied here

The 70% rule says your maximum allowable offer (MAO) is 70% of ARV minus rehab. It's a smoke test, not a precise formula, but it works as a quick filter.

In Boise, where ARVs typically sit in the $510k-$670k range, that math runs like this:

ARV: $670,000 (high end of comps)
70% of ARV: $469,000
Less $30k typical rehab: MAO = ~$439,000

If you can't buy under that, the math doesn't work. Use the fix-and-flip calculator for your specific deal.

What Idaho flippers actually deal with

Property taxes during holding: 0.63% statewide average. On a $510,000 purchase held for 6 months, that's $1,607 in taxes alone - not the largest line item but rarely budgeted by new flippers.

Permit + inspection cycles: varies by municipality but generally 2-6 weeks for typical scope (kitchen/bath, HVAC, electrical updates). Pulling permits matters - unpermitted work tanks ARV when the buyer's inspector finds it.

Holding costs to budget:

Mortgage/hard money interest: 10-12% APR on hard money is standard now. On $510,000 that's $4,675-5,100/mo
Insurance (vacant + builder's risk): $150-300/mo
Utilities + lawn care: $200-400/mo
Total: figure $1,200-1,800/mo holding cost on a typical Boise flip

A 6-month flip = $7-11k just in carry. That comes out of your spread.

What kills Idaho flips

Boise's pandemic-era spike has reset somewhat. Idaho Falls is the quieter cash-flow option.

The common Idaho-specific deal-killers:

Underestimating insurance during the rehab period. Builder's risk policies are usually findable but quote each one - underwriting standards have tightened.
Comping to the wrong street. Boise's neighborhoods can flip from B-class to C-class across a 4-block stretch. Use comps within 0.5 miles and don't trust auto-valuation models on transitional blocks.
Rehab scope creep. Lock the scope before close, get fixed-bid contracts where possible. Cost overruns of 20-30% are common and they eat the spread fast.

The actual go/no-go targets

For a flip in Idaho to actually work:

Profit margin: $25-40k minimum on a $200-350k ARV flip. Below $25k and one bad week of carry kills it.
Annualized ROI: 25%+ on cash-in. Lower than that and you're better off in a buy-and-hold.
Days on market estimate: <90 from listing. Boise still sells fast on price-right product.
Exit price as % of comps: 95-100% of the top comp, NOT the average. Don't expect to be the #1 comp on the street.

One advantage of flipping in Idaho - if you change your mind and decide to hold + rent, the landlord-friendly law gives you a cleaner exit path on a problem tenant later.

When Idaho is + isn't the right state for flipping

Idaho's higher price points mean each flip ties up significant cash, but the dollar profit per deal can be larger. Volume vs margin tradeoff. New flippers usually do better starting in cheaper markets.

Run your specific deal through the fix-and-flip calculator - holding cost reality and the 70% rule sanity check will tell you in 2 minutes whether to drive out for the walk-through or not.