Mufflers and Noise Level Limits

Boat operators may not hear sound signals or voices if the engine is not adequately muffled.

• A boat’s engine must have a factory-installed muffler or exhaust water manifold for noise reduction or another effective muffling system.
  • Boats built after January 1, 1993, must not exceed a noise level of 88 dBA.
  • Boats built before January 1, 1993, must not exceed a noise level of 90 dBA.
• If water is used for muffling, it must be in conjunction with a marine-designed exhaust manifold. Simply injecting water into an exhaust header does not satisfy the requirements for a muffling system.
• The use of cutouts or exhaust stacks is prohibited.
• Outboard motors, because of their exhaust design, do not require a muffling system.