I have a brochure with Utah's laws, and it states that all motorboats must be equiped with a muffler system. Boats manuf. before 1993 may not exceed 90 decibles, and boats made after jan. 1 1993 can't exceed 88 decibles. Bla bla bla and then it states that cut outs, or muffler bypass systems are illegal. Oddly it says nothing at all about water. I assume these laws vary state to state.