Are you confused by Idaho's property tax system?  You're not alone.  Ever wonder why taxes are higher in Boise than in Sun Valley, even though homes are much more expensive there?  Idaho's tax system isn't that confusing once you know how it works. 

Property taxes are levied (imposed) by the Counties in Idaho.  The county adds up the costs of providing all of it's services such as fire, ambulances, schools, libraries, and the like and comes up with a total dollar amount.  At the same time, they total up the appraised market value of the homes in the county, less any deductions like home owner's exemptions.  Once they have the budget and know the market values of the property, they simply work backwards to determine the tax (mil) rate.

For instance, let's say the County has a total budget of $1 Million and the total market value of all homes is $100 million.  In order to make their budget, they will have to get 1% of that amount.  The county actually breaks the budget out into numerous categories and home owners are only charged for the services they receive.  So, if you live in the county and do not receive city services, for example, you are not charged for them.  If you are receiving services, you pay your share of them.  Your share is equal to the value of your property divided by the total market value of homes receiving the SAME services.  

The cost of running a county or city government is about the same no matter where you go.  The streets in Sun Valley are paved with the same rock and asphalt as the streets in Nampa; they're not paved with gold!  Their sewer and water systems use the same basic components, and library books cost about the same amount to buy in both places.  I think you get the idea.  

So, it costs about the same amount (per person) to provide these services, but each home on average is worth much more in Sun Valley, so the county can charge a lower tax rate on each home to cover their budget.  The tax RATE is lower, but the total taxes collected (per person) is actually higher.  

As a general rule, the lower the average home price is in a county, the higher the tax RATE has to be to cover the government budgets.  Additionally, the bigger cities tend to have a lower rate than the smaller cities because they can achieve economies of scale.  Basically, they have purchasing power because they buy a lot of stuff and can get a discount on things.