Automotive Repair and Maintenance Shops

A study conducted by Union Sanitary District (USD) in the late 1990’s focusing on wastewater discharges from automotive machine shops to the sanitary sewer, found that in most cases, levels of copper, lead, nickel, zinc and oil & grease in the wastewater exceeded USD discharge limits and in some cases exceeded California hazardous waste discharge limits. The results indicated that the high pollutant concentrations were generated from various processes (hot tanks, solvent cleaning booths, floor drains, etc.) employed by many of these shops. As a result, USD has adopted the following discharge requirements for automotive machine shops: 


  • All automotive machine shops located within Union Sanitary District's service area are required to reduce the concentration of pollutants in their wastewater discharge to comply with local discharge limits, or to discontinue all process discharge to the sanitary sewer (this excludes bathroom discharges). 
  • All automotive shops, which possess a hot tank, must remove or permanently plug the tank's discharge port. 
  • No discharge of any kind may be redirected from the sanitary sewer to the storm drain. 


If a facility chooses to discontinue all process discharge to the sanitary sewer, all discharge points (including floor drains) must be disconnected and/or permanently plugged and sealed. The District must be notified when this action is completed. 


If a facility chooses to continue discharging to the sanitary sewer, the following conditions must be met: 

  • Compliance with all USD local discharge limits shall be maintained at all times. 
  • A completed permit application must be submitted to the District (including a wastewater characterization study). If a permit is determined to be required, then the applicant must pay all appropriate permit fees. The applicant is also required to sample the facility's process discharge once every quarter, have these samples analyzed by a California certified laboratory, with the results submitted to the District. 

If at any time, the facility's process discharge is found to be out of compliance with any pollutant covered under USD local or Federal discharge limits, the facility shall install the appropriate pretreatment system. 

Please direct any questions you may have regarding these requirements to the environmental compliance department at Union Sanitary District.



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5072 Benson Road

Union City, CA 94587-2508

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