Unless your establishment is going to be connected to a septic system, our department does not make this determination. If you will be operating within the City of Great Falls, the Public Works Environmental Division will determine if you need a grease interceptor or grease trap. You can contact the Sector Control Compliance Technician at (406) 727-8390. You can find additional information and resources on their website and in the FOG Manual. If you will be operating outside of Great Falls, you'll need to contact the wastewater operator for your municipality or public water and sewer district.