Significant industrial user

Definition

The discharge tier that decides whether the sewer authority writes you a permit.

Why It Matters

No federal standard covers car washes at all. The nearest category expressly excludes facilities that clean only the exteriors of transportation equipment, so the rule that binds is the local sewer authority's. The threshold it uses is federal: twenty-five thousand gallons a day of process wastewater, or five percent of the treatment plant's capacity, or a designation by the authority. What a sale does depends on who wrote the permit. A local discharge permit is required by federal rule to state that it is not transferable without prior notice. EPA's model ordinance for local authorities allows a transfer only on advance notice and the authority's approval, and voids the permit on the transfer date if no notice came. Washington's state waste discharge permit transfers automatically on a dated written agreement between the parties, unless the department calls for a modification. Ask which one the wash holds before the first meeting.