Hi @Angela Zaitz!
Congrats on taking the next steps!
Regarding permitting for the ADU, it's essential to check the local regulations and building codes in your area. Each jurisdiction may have specific requirements for creating an ADU, including permits and inspections. Contact your local building department or zoning office to inquire about the necessary permits and any specific guidelines that need to be followed for creating an ADU. Usually, if you are a homeowner the building/zoning department are a little more sympathetic. They will provide you with accurate information based on your location.
Regarding utilities, splitting them between two units can be managed, but it can vary depending on your local regulations and the existing infrastructure. Here are a few general suggestions:
1. Separate Electrical Metering: Contact your utility company to inquire about the process of installing a separate electric meter for each unit. This allows for individual billing and usage tracking. I highly recommend doing individual billing for electric since those costs can wildly vary especially if you have high heating/cooling needs.
2. Water Heater: While some jurisdictions may require separate water heaters for each unit, others may allow a shared water heater under certain conditions. Check with your local building department to determine the specific requirements. If you are able to share one water heater, make sure to increase its size of it to handle the increased usage. I usually recommend having one water heater for each unit but piping may not allow that or get to costly.
3. Submetering or Separate Utility Accounts: If separate utility meters are not feasible or allowed, you could explore the option of submetering, where individual units have their own utility usage measured. Alternatively, you can establish separate utility accounts for each unit and split the bills accordingly. As mentioned by Angela, you can charge by sqft as well or another option would be a flat fee. Just know with the flat fee you are potentially more liable for utility overages.
Remember, it's crucial to consult with professionals, such as a local contractor, architect, or building inspector, to ensure compliance with local regulations and building codes. They will provide specific advice based on your unique circumstances and location.