Private Site Developments

The Engineering Department reviews and provides engineering approval of site plans for the following types of developments on private property, as a pre-approval for the Building Department and/or Zoning Department:

  1. Demolition of an existing structure
  2. Construction of a new house
  3. Improvement(s) to an existing house / property that add 400 square feet of new impervious coverage including but not limited to additions, pools, patio or deck, or driveway.

Impervious Coverage Definition

Impervious coverage is defined as any surface that has been compacted or covered with a layer of material so that it is highly resistant to infiltration by water.

Impervious surfaces include:

  • Asphalt
  • Concrete and stone roads
  • Driveways
  • Parking lots
  • Pools and patios
  • Porous asphalt or concrete
  • Roofs
  • Sidewalks

Outside Agency Approval

Outside Agency Approval is required prior to the Engineering approval for the following:

  • Disturbance of 5,000 square feet or more - Mercer County Soil Conservation District (MCSCD) approval
  • Wetlands or flood hazard area encroachment - New Jersey Department of Environmental Protection (NJDEP) approval.
  • Any disturbance on properties within a C1 Riparian Buffer may require NJDEP approval.

Visit the Department of Environmental Protection (DEP) for more information.

Site Inspections

During construction, the Engineering Department will perform periodic site inspections to assure compliance with the following areas of Engineering approval:

  • Stormwater management (drywells, raingarden, roof leader piping, etc.)
  • Final site grading prior to seed or sod
  • Curb, sidewalk, and roadway excavations for utility connections within the public right-of-way

Stormwater Management 

Stormwater Management INFOGRAPHIC for Small Projects (PDF)

Ordinance 2020-38 Stormwater Regulations for Major and Minor Development (PDF)

Ordinance 2020-39 Stormwater Regulations for Small and Large Projects (PDF)

Final Inspection

Upon completion of construction, the Engineering Department will complete a final inspection prior to consideration of providing a pre-approval for a Certificate of Occupancy. Please note, the applicant must contact Mercer Soil Conservation District for final compliance inspection and certification; the Engineering Department will not issue a pre-approval without MCSCD acceptance.