For those of you curious, here is the littering RSA (and it does include throwing objects form boats into waterways)
TITLE XII
PUBLIC SAFETY AND WELFARE
CHAPTER 163-B
LITTER CONTROL LAW
Section 163-B:3
163-B:3 Unlawful Activities. – It shall be unlawful for any person or persons to dump, deposit, throw or leave, or to cause or permit the dumping, depositing, placing, throwing or leaving of litter on any public or private property in this state, or in or on ice or in any waters in this state, unless:
I. Such property is designated by the state or by any of its agencies or political subdivisions for the disposal of such litter, and such person is authorized by the proper public authority to use such property;
II. Such litter is placed into a litter receptacle or container installed on such property;
III. Such person is the owner or tenant in lawful possession of such property, or has first obtained consent of the owner or tenant in lawful possession, or unless the act is done under the personal direction of said owner or tenant, all in a manner consistent with the public welfare.
Source. 1971, 144:1, eff. July 25, 1971.
In addition, RSA 163-B:6 authorizes any law enforcement official in the State to enforce littering regulations.
Finally, back to PROPELLOR's observation that gray water regulations are more the area of enforcement of DES officials, he is exactly right....those regulations are typically handled by DES officers. And believe me, you don't want to get on the wrong end of DES in one of these cases!
