MAINE GOV. SEPTIC SYSTEM PLAN RETRIEVAL
This link will take you to Maine's Septic Plan Archive's. If your home pulled permits to build a septic in the past then you should find the septic plans here for your existing home.
LAKES ENVIRONMENTAL ASSOCIATION
LEA is a great resource for those who want to know what is environmentally sound for the environment in which we live. If you are building on or near water it is always a good idea to reach out to them with any questions you may have.
Maine State Law dictates that anyone who is doing groundwork must notify their local utility companies. Digsafe provides a free service where they will come out and survey the land for the location of any underground utility cable and mark them. They then communicate with the utility companies and issue a permit number with their findings.