Mercer County, NJ septic permits and regulations

Septic systems in Mercer County, New Jersey are permitted by Mercer County Office of Environmental Health under N.J.A.C. 7:9A.

Septic permit program

  • Program type: County Health Department
  • Authorized agent: Mercer County Health Department
  • Own septic program: No, uses New Jersey state rules
  • Local rules beyond the state: No
  • Population: 387,340

Permit fee comparison

Average septic permit fee in Mercer County: $250. New Jersey average: $242.

Local rules

County operates under state-level NJAC 7:9A. Contact local health department for any additional county-specific requirements.

What SepticPro has on file for Mercer County

  • 22 permit fees with sources
  • The agency phone, email and office address
  • Setback distances
  • Soil and perc test requirements
  • Allowed system types
  • System design rules
  • Inspection requirements
  • Maintenance and pumping rules
  • Point-of-sale rules
  • Installer, designer and pumper licensing

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Draw a permit-ready site plan for Mercer County

Enter the address, draw the system on the aerial with the parcel lines and topo, and print it to scale for Mercer County Office of Environmental Health. See how SepticPro site plans work.

Other New Jersey counties

Data checked 2026-05-11. Always confirm requirements with Mercer County Office of Environmental Health before applying.