California's Exhaust Regulations

California's Exhaust Regulations

Last Updated August 8, 2023 | Meghan Drummond

Important Update: September 30th, 2019

Thanks to the dedication of enthusiasts and the organizational efforts of SEMA, "Fix-it" Tickets have been reinstated which allows owners 30 days to fix an overly loud exhaust without incurring a fine. This is an important moment for the automotive community and proves the value of organizing and spreading awareness. Certainly, without SEMA this victory wouldn't have been possible.

Even if you're not a fan of a loud exhaust, this change is still positive. Without due process, it was difficult for anyone to know what was and wasn't an acceptable exhaust system. The decibel limit on aftermarket exhaust systems still hasn't changed, but your odds of getting saddled with a thousand dollar fine are substantially lower than they were yesterday.

Because of the specific language of the amendment, this legislation goes into effect today, instead of at the beginning of January.

A heartfelt congratulations are in order for California auto enthusiasts and the dedicated folks at SEMA. We are leaving this article up for anyone who is interested in how the law has been changed over the past couple of years and what problems were created that needed to be addressed by this action.

2019 Law Changes

On January 1, 2019, technically nothing changed regarding California’s laws against “excessively loud” exhaust systems. What changed were the penalties. Before this legislation passed, car owners who were cited for exhaust noise had the option of getting the problem corrected to avoid a fine. Now, there’s no getting around it: if you’re cited, you’re getting a fine. Even though the minimum is $25, with court fees that quickly turns into $200. The max fine is $1,000.

Obviously, this has resulted in a lot of people wondering what defines excessively loud, how they can avoid a ticket, and what exactly are car enthusiasts supposed to do if they want to modify their exhaust but don’t have $1,000 to throw away every time they get pulled over.

What’s Excessively Loud?

An aftermarket exhaust system about to be installed

Over 95 decibels for all vehicles under 6,000 pounds is deemed excessive and therefore prohibited. 95 decibels is actually really loud. In the above video you can watch Bill test some modified exhausts and despite having a substantial roar, they’re still within the passing range.

As a measure, a subway train at 200 feet makes about 95 decibels.

If you can’t hear your exhaust unless it’s that loud, it’s time to consider the possibility that you have some hearing loss. Regular exposure over 90 decibels can lead to permanent hearing damage.

How Do Police Check Decibels?

Cell Phone displaying decibel meter

This is a subject of some dispute. What is supposed to happen is that a cop will hold a decibel reader twenty inches from your tailpipe and then ask you to rev the car to 3-5,000 RPM. Some Californians have complained that no such test was performed and that the cop simply heard or saw their exhaust and wrote a ticket. This is a time where cell phone recording or dash cam recording can come in handy. Ask the officer who is writing you a ticket what the decibel reading was. Let them know they are being recorded as stating that there was no test conducted.

How Can You Check Decibels?

Double checking your exhaust is a good way to make sure your modifications are fine. There are several decibel meter apps available so that you can check your exhaust with your smartphone.

Decibel X (iphone and Android)

Sound Meter(Android)

NIOSH Sound Level (iPhone)

Why the Change?

Ford Performance Exhaust being installed

There are many wondering why exactly this change is happening now, and there are a lot of theories depending on who you listen to.

According to many the change is because of an effort by the California government to address an increase in road fatalities that are being attributed to street racers. In cities like Los Angeles, this is definitely a contributing factor, but having a modified exhaust doesn’t mean that you’re racing illegally.

That said, we all know someone who uses the power of a V8 for evil at three in the morning while driving through a residential neighborhood, so some blame belongs to those as well. The law has been around since the ‘90s, but because of the leniency wasn’t being taken seriously by many. Unfortunately, this is basically why we can’t have nice things. Laws that aren’t punitive tend to be disregarded.

What Do I Do if I’m Unfairly Targeted?

Already there have been reports of people getting a ticket despite having an exhaust they know is within the limit, or even having a stock exhaust. If you feel that you’ve been given a ticket unjustly then it is your right to contest that ticket.

You can have your vehicle tested at a California referee center by calling 1-800-622-7733. If your vehicle meets the standard then you’ll be given a certificate of compliance.

It’s important to note that depending on your other modifications, any exhaust system can be rendered noncompliant. These are the ones we know are compliant without accounting for other factors. Fifty-State legal exhaust systems help with ensuring compliance, but they don't guarantee it.

If you’re on CJ’s, we’ll also tell you if the exhaust should be legal in all states. All you need to look for is this line, which will specify whether or not a state is fifty-state legal. If it is, you’re good to go! Even though you need to keep your decibel readings low, you can still have a great exhaust note.

A line from CJ’s parts catalog specifying that exhaust is 50 State legal

Sources:California Bureau of Automotive Repair | California's New Exhaust Noise Bill, MotorTrend | Fact vs Fiction: California's New Exhaust Noise Law, SEMA Action Network | Are You at Risk for Hearing Loss?, Hearnet |

This article was researched, written, edited, and reviewed following the steps outlined in our editorial process. Learn more about CJ's editorial standards and guidelines.