Iowa Extends Overweight Harvest Permit Waiver Through December 6, 2026

Iowa grain, fertilizer and manure haulers can run at 90,000 pounds gross vehicle weight without a permit through December 6, 2026, under a proclamation Governor Kim Reynolds signed effective immediately.

The order applies to trucks moving corn, soybeans, hay, straw, silage, stover, dry, liquid and gas fertilizer, and dry and liquid manure. It covers all highways within Iowa except the interstate system. That interstate exclusion matters for haulers routing to Mississippi River terminals and processors, who must return to the standard 80,000-pound federal limit once they reach interstate pavement.

What does the proclamation change for haulers?

The practical gain is capacity and paperwork. A 90,000-pound gross load against the normal 80,000-pound limit means roughly 12.5 percent more payload per trip, assuming axle limits hold. That translates into fewer trips per bin, per fertilizer shed and per manure pit during the application and harvest windows — a direct lever on trucking cost per bushel and per gallon of manure hauled.

The waiver also removes the permit requirement itself. Carriers do not need to file for overweight authority to use the provision. Conditions still apply, and enforcement will check them:

• Loads must not exceed 90,000 pounds gross weight.
• Axle weights must not exceed the non-primary highway maximum gross weight table in Iowa Code § 321.463 (6) (a)-(b) by more than 12.5 percent.
• No axle may exceed the legal maximum of 20,000 pounds.
• Trucks must comply with posted limits on roads and bridges.

Why weight waivers matter at the margin

For corn and soybean growers, trucking is a visible line in the harvest budget. Fewer trips cut fuel, labor and equipment hours at exactly the point in the season when combines, grain carts and semis are all committed. For livestock operations, the same arithmetic applies to manure application ahead of the next cropping cycle, and to fertilizer movements as retailers position product.

The 12.5 percent axle tolerance gives drivers room to load to the 90,000-pound ceiling without a single heavy axle triggering a violation, but the 20,000-pound per-axle cap and posted bridge limits remain hard constraints. County and local road authorities retain the final word through their posting decisions, so routes should be checked locally.

Iowa has used harvest-season weight waivers repeatedly in recent years, and this extension carries the provision through December 6, 2026 — covering not only this fall's row-crop harvest but also spring fertilizer and manure movements in 2026, depending on how the calendar overlaps future proclamations.

Haulers moving grain across state lines should confirm neighboring states' rules before loading to 90,000 pounds, because the proclamation's authority ends at Iowa's borders and at the interstate ramps.