Mont. Code § 75-6-322
In the discretion and at the option of the governing body of the authority, bonds may be secured by a trust indenture by and between the authority and a corporate trustee, which may be a trust company or bank that has the powers of a trust company within or outside of the state. However, a trust indenture may not convey, mortgage, or create a lien upon the water supply, wastewater transportation, or treatment system, any part of the system, or the authority or its member public agencies. The resolution authorizing the bonds and fixing the details of the bonds may provide that the trust indenture may contain provisions for protecting and enforcing the rights and remedies of bondholders as may be reasonable and proper and not in violation of law, including covenants setting forth the duties of the authority and the members of its governing body and officers in relation to the construction or acquisition of the water supply, wastewater transportation, or treatment system and the improvement, extension, operation, repair, maintenance, and insurance of the bonds and the custody, safeguarding, and application of all money. The resolution may also provide that all or any part of the construction work must be contracted for, constructed, and paid for under the supervision and approval of consulting engineers employed or designated by the governing body and satisfactory to the original bond purchasers, their successors, assignees, or nominees, who may be given the right to require that the security given by contractors and by any depository of the proceeds of bonds or revenue of the water supply, wastewater transportation, or treatment system or other money pertaining to the supply or system be satisfactory to the purchasers, their successors, assignees, or nominees. The indenture may set forth the rights and remedies of the bondholders and the trustee.
§ 75-6-322, MCA