Verified 2026-08-26

Failed emissions in Colorado? What the waiver costs

Colorado sets four different thresholds depending on what fuel your car burns and what year it was built — and diesel owners face the steepest figure in the country.

An older sedan with its bonnet raised in an empty inspection bay

The number

For an ordinary petrol car from 1968 or later on regular plates, the figure is $715 in emissions-related repairs within the last six months. A 1967-or-older petrol car needs only $75. Light-duty diesel at 14,000 lbs GVWR or under needs $750, and heavy-duty diesel above that needs $1,500 — the highest single emissions waiver threshold we found anywhere in the United States.

What counts, and what disqualifies you

Colorado also wants the timeline tight. The failed test must be no more than six months old, the repairs must fall inside the same six months, and you need a second failed test after the repairs proving they did not fix it. Let any of those drift and the application resets.

Why Colorado’s figure looks like this

Colorado is one of the few states to split its thresholds by fuel type as well as by year, which is why a diesel owner here faces a figure no petrol owner in the country meets. The hub compares every state we verified and quotes the federal regulation the whole structure derives from.

When the number is bigger than the car

The diesel figures are where this bites hardest. A heavy-duty diesel owner facing $1,500 before Colorado will register a truck that still fails is looking at a genuine business decision, not a repair bill. And on a 1970s petrol car the $75 threshold is so low that reaching it is almost never the question — whether the car is worth keeping at all usually is.

Whatever tier you fall into, the six-month clock is the thing to watch — letting the failed test age out means starting the whole sequence over rather than losing only the money. Selling a car that failed emissions in Colorado is an ordinary private sale.

Sources

Colorado DMV / Air Care Colorado — Colorado emissions waiver — Where the Colorado figure above was read, on 2026-08-26
40 CFR 51.360 — the federal waiver rule — The federal floors behind what Colorado asks for

Common questions

What people ask about this

What is the emissions waiver amount in Colorado?

$715 for petrol vehicles from 1968 onward on regular plates, $75 for 1967 and older, $750 for light-duty diesel at or under 14,000 lbs GVWR, and $1,500 for heavy-duty diesel above that.

How recent do my Colorado repairs have to be?

Everything sits inside a six-month window: the failed test must be no older than six months, the repairs must have happened within the last six months, and a second failed test after those repairs is required.

Why is the Colorado diesel threshold so high?

Heavy-duty diesel sits in its own category at $1,500, reflecting how much more expensive diesel emissions equipment is to repair. It is the highest emissions waiver figure we located in any state.