In order to get a septic permit in Carbon County, there are a few items you must have addressed first. A Floodplain Permit from the Carbon County Floodplain Administrator, approval from Montana Sage Grouse Habitat Preservation Program, Carbon County Development Permit from the Planning Department, Carbon County Road Department Road Approach Permit, and Rural Address Assignment from Carbon County Disaster and Emergency Services (see flowchart here). For more information contact the individual department you are requesting additional information from.
When the above-mentioned permits have been obtained you are ready to apply for a septic permit. In order to get a construction authorization and subsequent permit for a septic system in Carbon County you must first have an approval statement issued by either the Montana Department of Environmental Quality (MTDEQ) or by Carbon County.
If your property is less than 20 acres (not counting county road frontage), it needs to have a Certificate of Subdivision Approval from MTDEQ. This document designates the approved water and wastewater facilities and number and type of structures for the property. It is the responsibility of the developer or current owner to provide copies of these documents to purchasers. You can search Carbon County archives for the MTDEQ approval (here), for a nominal fee. If the property has not been issued an approval statement by MTDEQ you will need to hire a consultant to submit an application to MTDEQ for an approval before a Carbon County septic permit can be applied for. Please know the application process through MTDEQ is a time intensive process that does not involve Carbon County. To contact a consultant that can submit the application on your behalf and answer any questions you have, please see this (list). You may also call MT DEQ at 406-444-4400.
If your property is greater than 20 acres (not counting county road frontage) you need a sanitary approval issued by Carbon County. All properties greater than 20 acres have sanitary restrictions that must be lifted by obtaining a Carbon County sanitary approval or septic permit before any water or wastewater facilities can be constructed. Unless the developer or current owner can provide documentation of a local Carbon County sanitary approval or septic permit, an authorized consultant will need to submit plans for water and wastewater approval to Carbon County on your behalf. The data required for an approval can be seen (here) along with the associated (fee schedule). To contact a consultant that can submit the application on your behalf and answer any questions you have, please see this (list). Please know that only systems (including gray water disposal) that are designed by an authorized consultant and approved by Carbon County are allowed. Holding tanks, outhouses, porta-potties, etc. are not allowed in Carbon County.
When a property has an appropriate approval statement as well as all other required county and state permits, a Carbon County Septic Application can be submitted (here). Septic permit applications are reviewed in the order which they are received. Please allow 7-14 days for processing and up to 30 days before receiving an authorization to begin construction of the septic system. Completed construction authorization documents will be sent to the address provided in the application. Do not begin construction without a valid construction authorization form in your possession. You must provide copies to your contractor. The contractor can then begin construction and must call before 3pm the day prior to being ready for an inspection to request an inspection and get it scheduled on the sanitarian calendar. Upon completion of a compliant septic system inspection, the sanitarian will issue a Carbon County septic permit.