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Q & A
Motorboat Decibel Levels
Can you tell me the allowable decibel levels for a boat in Pennsylvania? How far does the tester have to be away from the boat, on and off shore? We have a "Jet Boat" and it can have a muffler on it. The only complaints we get about the noise are from Fish and Boat Commission Conservation Officers, not from the local police.
Our regulations contain several provisions related to motorboat noise. As a general principle, all motorboats must be equipped with a muffler in good working order to prevent excessive or unusual noise. It's illegal to bypass a motorboat's muffler subsystem or to alter or remove it.

Our regulations contain provisions for both stationary and pass-by tests of motorboat noise. For a stationary test, the noise may not exceed 88 decibels or 90 decibels depending on the date of manufacture of the motor. The pass-by test, which involves use of a sound meter as a boat passes by, specifies a noise level not to exceed 82 decibels. 

Finally, our regulations also contain a provision making it illegal to operate a motorboat creating noise so "abnormally loud as to constitute a substantial and extraordinary annoyance or distraction to persons in the vicinity of the watercraft."

It sounds like you want to do the "right thing," and that is appreciated. Because waterways conservation officers have primary authority (and specialized training) in this and other boating issues, it is somewhat understandable that a local police officer would hesitate to become involved. If complaints are levied, even to a local police department, it would be customary that such be referred to our officers.

Our conservation officers report that, in their experience with inboard jet drives (assuming that is what you have), they can be significantly muffled with water baffles. The noise and speed can be exhilarating, but as you apparently recognize, we have to share the waters and surroundings with others. Your respect of that goes a long way.

There are a few resources on the web that provide more information on motorboat noise levels. The complete text of the regulations on motorboat noise is found at Chapter 119 of the fishing and boating regulations (58 Pa. Code Ch. 119). It can be found on the web at

The Personal Watercraft Industry Association (PWIA) has an excellent page on the subject of watercraft. Here is an excerpt on the J34 and J2005 standards quoted from the Society of Automotive Engineers (SAE):

SAE J34: The most precise measurement available, taken of a boat at a distance of 50 ft. with wide-open throttle (the near maximum noise of the boat). Although great for engineering standards, it is difficult for enforcement purposes in the field. The Coast Guard recommends 86 decibels (dBA), which most states have adopted as law.

SAE J2005: This measures the engine sound at idle with the microphone 1.5 m away. SAE recommends a limit of 90dbA for this method, which does not account for the speed or power of the boat.

SAE J1970: In realizing the enforcement difficulties of the previous methods, SAE designed this shoreline noise test enabling regulations keeping the boat under 75 dBA at 50 ft. by operation, not mechanics. The operator is responsible for controlling the noise of the boat.

Sound energy dissipates with distance, other sound and wind. A comprehensive study on sound with motorboats (but not including PWC) found that sound dissipates up to 9.9dBA when the boat travels from 50 ft to 200 ft away (4.8 dBA reduction from 50 to 100 ft, additional 5.1 dBA reduction from 100 to 200 ft.).

Both the National Association of State Boating Law Administrators (NASBLA) and the National Marine Manufacturers Association (NMMA) have Model Noise Acts, which our manufacturers follow as NMMA members. These requirements are in compliance with the SAE recommended dBA standards. NASBLA requires 88 dBA under SAE J2005, and 75 dBA under SAE J1970. NMMA recommends 90 dBA under SAE J2005. The Environmental Protection Agency has determined that 75 dBA at 50 feet is an acceptable noise level to protect public health and welfare.

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PA Boating Handbook
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