Joint DNR/Commerce
Plan Review Procedures for Large POWTS

Private Onsite Wastewater Treatment Systems (POWTS) that are determined to be "Large" will be subject to a joint plan review conducted by the Departments of Natural Resources (DNR) and Commerce (Commerce), and will receive Wisconsin Pollutant Discharge Elimination System (WPDES) permit coverage from the DNR. The Department will issue coverage under "General Permit" (opens in new window) (Permit No. WI0062901) if the proposed system satisfies the criteria for the General Permit. If the system does not qualify for a General Permit, the Department will issue coverage under an individual (specific) permit. The joint plan review procedure does not apply if the POWTS is owned by a municipal entity and the municipal system serves more than one building.

For some project proposals, the first step of the process will be to verify that the proposal will be defined as a "Large POWTS". In situations where the design flow is close to 12,000 gpd (or 85 residential bedrooms), or where multiple smaller systems under single ownership are involved, it is recommended that the applicant contact the applicable Commerce and/or DNR plan reviewer. Some initial information about the proposal and design flows may then be requested and reviewed to confirm whether a DNR WPDES permit will be required.

If a project proposal is subject to a WPDES permit, it is recommended that the applicant submit a preliminary design report to both DNR and Commerce prior to the preparation and submittal of detailed construction plans and specifications. This should enable a resolution of facility design and site issues prior to expending work efforts on a specific design. See "Preliminary Design Report Guidance" for more information.

The review of the preliminary design report should result in concurrence on a proposed treatment system, including the type and location of the subsurface disposal component. The possible need for groundwater monitoring wells or other monitoring devices will also be determined as part of this review.

Once the preliminary design report review is completed, the DNR will provide a WPDES permit application form. The WPDES wastewater permit issuance process (opens in new window) for an individual permit (not the General Permit) includes public notification and an environmental assessment review. The applicant for an individual permit should normally provide the environmental assessment information (opens in new window) with the preliminary design report. The WPDES permit application must be submitted at least 180 days prior to the anticipated start of the system discharge. If the project qualifies for a General Permit, the public notice and an environmental assessment are not routinely required. Click on this link for more information on the Large POWTS General Permit (opens in new window).

Construction plans and specifications for the recommended system should then be prepared and submitted to Commerce. A copy should also be forwarded to DNR. Commerce and DNR will conduct a joint review and Commerce will issue the plan approval after a concurrence letter from DNR is provided. If groundwater monitoring wells are required, the construction plans for the wells should be submitted separately to the WDNR for plan approval. Groundwater monitoring wells must be designed and constructed in accordance with ch. NR 141, Wis. Adm. Code (PDF, exit DNR, opens in new window).

A County Sanitary Permit must be obtained in addition to the WPDES permit. Construction may commence prior to the WPDES permit issuance, but a system cannot start discharging until the WPDES permit is issued. After the WPDES permit is issued, the owner may initiate operation in accordance with the terms and conditions of the permit.