Construction Services & Inspections

Basic Information

The Minnesota Plumbing Code is the standard to protect people and the environment from health hazards. The water supply and distribution rules help ensure a safe water supply, while the sanitary drainage rules protect our health and environment. The regulations for storm drainage work in conjunction with other entities, such as the EPA or DNR, prevent erosion and protect our natural waterways. Gas piping rules can be for gas which is run to a residential home for the furnace or stove but can also apply to the MED-Gas used in hospitals or Compressed Natural Gas (CNG). A tracer wire needs to be installed next to buried pipes.

Commercial or Residential Projects

All projects involving piping follow the same code book, whether it is a commercial or residential project. The plumbing permit must be taken out by a plumbing contractor licensed by the Minnesota Department of Labor and Industry (DLI), except the owner of a single-family owner-occupied home may take out a permit. If you are interested, you can find more information regarding necessary licensing and bonding for contractors.

Plumbing

A Plumbing Permit is needed for plumbing work (water, sewer, or stormwater) on private property. Water, sewer, and stormwater piping in the right-of-way are addressed by the Engineering Department and may require additional permits. An excavator contractor or other company with a pipelayer's card may install piping under the ground from the right-of-way to the building’s exterior. Simple pipe repairs or replacing a simple fixture or faucet does not require a plumbing permit, if piping is not touched. 

Plumbing Plan Review

The following projects require a plumbing plan review:

• Projects with more than 25 openings
• Food facilities
• State-licensed facilities (hospitals, nursing homes, correctional facilities, etc.)
• Public buildings (school districts or charter schools)
• Other projects of a special nature (dialysis facilities or other special projects where a plan review is requested)

For most projects, Construction Services is the responsible party for plumbing plan reviews, and files can be submitted with your permit application.

For certain buildings, The Minnesota Department of Labor and Industry (DLI) is the responsible party for plumbing plan reviews:

• State Licensed Facilities: Hospitals, nursing homes, supervised living facilities, or free-standing outpatient surgical centers, boarding care homes, residential hospices, or similar state-licensed facilities
• State owned buildings: Correctional facilities, State Colleges and University (MNSCU) buildings, State Agencies (DNR, MNDOT, etc.) and other state-owned buildings 

For these buildings, send plans directly to DLI for review. The approved letter and plans should be uploaded when applying for a plumbing permit for one of these types of projects.

More information about who is responsible for plumbing plan reviews can be found here.

Plumbing Inspections

Plumbing inspections must be requested prior to any work being covered within the walls, ceilings, floors, or earth. More information about inspections can be found here. Typical plumbing inspections include rough-in, air test, under floor plumbing, outside water or sewer service, and final inspection.

Lead Service Lines

The City of Duluth is replacing lead pipes in various neighborhoods. See the Engineering Department for more information or view the Minnesota Lead Inventory Tracking Tool to see if your property might have lead pipes.

Gas Piping

Gas piping permits are needed for new or replacement gas lines for items such as fireplaces, furnaces, or water heaters, testing of existing gas piping that has been shut off at the meter for more than 6 months, and for underground fuel lines from a residence to an accessory structure. A gas piping permit is not needed when replacing appliances and equipment that has an existing shutoff to the appliance or equipment. Gas piping may also be needed for MED-GAS Piping or Compressed Natural Gas (CNG) fueling stations.

Gas Piping Plan Review

Gas piping review is needed for projects that have underground fuel lines.

The Minnesota Department of Labor and Industry (DLI) is the responsible party for all piping reviews for certain buildings such as:

• Hospitals, nursing homes, supervised living facilities, or freestanding outpatient surgical centers, correctional facilities, boarding care homes, residential hospices, or similar state-licensed facilities
• State-owned buildings or state-agency-controlled buildings
• School district or charter school building projects
• Projects of a special nature, including dialysis facilities and other projects for which a department plan review is requested by either the City or the State

For these projects, submit plans for review directly to the Minnesota Department of Labor and Industry. The approved letter and plans should be uploaded when applying for a plumbing permit for these types of projects.

Buried Fuel Lines/Underground Gas Piping from the principal building to an accessory building on the same site, such as running a gas line from your house to your garage, need additional information for the Engineering Department. When applying on ePlace for a gas piping permit, if you select that it is underground, you will be prompted to complete a Buried Fuel Line application from the Engineering Department. This is needed, in addition to the Construction Services & Inspections permit, as a way to monitor gas usage in the City of Duluth. Once both permits have been applied for, reviewed, and paid, the permits will be issued. A tracer wire must be installed next to underground gas lines.

Gas Piping Inspections

Gas inspections must be requested prior to any work being covered within the walls, ceilings, floors, or earth. More information about inspections can be found here. MED-GAS piping and storage needs an inspection from the Fire Marshal's office. Call the Fire Marshal and provide the permit number and address when requesting an inspection. Follow the instructions for any inspections by the Engineering Department on their buried gas line permit.