The School Infrastructure Local Option (SILO) is a 1% local option sales tax adopted on a county by county basis in Iowa, United States.
Although the tax is collected by county, state mandate says the total amount collected is to be pooled and shared between the school districts.
SILO was developed in 1998 by the Iowa General Assembly to give school districts a revenue options other than the property tax.
As of late 2005, only Linn and Johnson counties in Iowa had not enacted a SILO tax.
In the spring of 2006 the Iowa legislature encouraged the two remaining counties to join the other 97 counties which had enacted this tax by offering an incentive provided the tax was enacted by July 1, 2008, allowing the districts to keep 100% of the money generated for the first half of the time it is collected instead of pooling it statewide.