Bolthole Index

Union County, New Jersey

Building permits, zoning and septic in Borough of Mountainside, New Jersey

Borough of Mountainside, New Jersey generally requires a construction permit to build, enlarge, alter or demolish a structure.1 In Union County’s Borough of Mountainside, the borough Construction Department issues building permits, and borough officials administer zoning.23 Septic construction, repair and abandonment have a borough permit category; New Jersey also requires approval from the board of health having jurisdiction before covered construction begins.45

At a glance

Building permits
Generally required for construction, enlargement, alteration and demolition1
Zoning
Borough zoning applies; requirements vary by district3
Septic permits
Borough permit category covers new systems, repairs and abandonment; health approval also applies45
Residential lot size
R-2 minimum: 15,000 square feet6
Zoning application fee
$50, non-refundable, with a current property survey7
Owner drawings
Applicants may draw plans for their own single-family dwelling; required approvals still apply8
Private wells
NJDEP drilling permit plus municipal or county health construction approval9

Who to call

Building permits

Mountainside Construction Department

Building permits, construction inspections and permit-status inquiries

908-232-2919

[email protected]

Online permits →

Zoning

Mountainside Engineering/Zoning Department

Borough zoning review, engineering approval and parcel-specific land-use questions

908-232-2409

[email protected]

Septic permits

Mountainside Health Department

Health-office contact for septic and private-water approval questions; confirm the administering office for the parcel

908-789-4070

[email protected]

Planning & zoning

Union County Planning Board

County review of site plans and subdivisions affecting county roads and drainage facilities

Contact details are copied from each office’s official page and were checked against it on October 11, 2026.

Off-grid gear

Going off-grid in Borough of Mountainside means bringing your own water and power. The kit we’d start with:

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Do you need a building permit in Borough of Mountainside, NJ?

Borough of Mountainside generally requires a construction permit to construct, enlarge, alter or demolish a structure.1 Ordinary-repair examples that do not require a construction permit include replacing gutters, replacing interior trim in a single-family dwelling, and repaving an existing driveway without changing its size or lot coverage.1 Expanding a driveway, walkway or patio requires a separate zoning permit regardless of the material used.10 Work without a required construction permit can bring a fine of up to $2,000.1

Mountainside allows applicants to prepare drawings for their own single-family dwelling, but that permission does not waive construction permits, zoning approval or code compliance.8

Who issues building permits in Borough of Mountainside?

The Mountainside Construction Department issues residential, commercial and industrial building permits; call 908-232-2919 for construction-office assistance.2 Mountainside’s Engineering/Zoning Department is the borough contact for zoning and engineering review at 908-232-2409.11 Zoning and construction application forms are available from the Construction/Zoning/Engineering Department on the second floor of Borough Hall.11

The Construction Department’s SDL portal supports property permit-status checks and online inspection appointments.2 For additions to homes or other buildings, the Borough Engineer must approve zoning compliance before a construction permit is obtained.11 Septic and private-water approval questions should also go to the Mountainside Health Department at 908-789-4070; ask the health office to identify the approving authority for the address.1213

What does zoning mean for a Borough of Mountainside lot?

Borough of Mountainside has municipal zoning, and district-specific requirements control the design of a proposed home.3 In Mountainside’s R-2 residential district, the minimum lot area is 15,000 square feet.6 R-2 front and rear setbacks are 30 feet, and the side setback is 10% of lot width or a minimum of 10 feet.14 R-1 has the same stated front, rear and side setback figures.15

Mountainside’s R-2 limits the building footprint to 15% of lot area and total lot coverage to 30%, including driveways, walkways, patios and other impermeable surfaces; maximum building height is 35 feet.1617 The combined coverage limit means paving belongs in the design calculations alongside the home’s footprint.16 Ask Engineering/Zoning to confirm the parcel’s district and the proposed layout before commissioning final plans.11

How do septic permits and wells work in Borough of Mountainside?

Borough of Mountainside lists a septic permit for new systems, repairs and abandonment.4 New Jersey requires the board of health having jurisdiction to certify proposed water supply and sewerage facilities before a building permit for a covered realty improvement is issued or construction begins.5 Septic tanks, drain fields and other covered sewerage facilities must be inspected by an authorized health-board representative and receive permission before being covered from view.18

Contact the Mountainside Health Department to confirm the septic application route and the health authority responsible for the site.1213 A proposed private well requires a New Jersey DEP drilling permit, with municipal or county health officials issuing the well-construction permit and necessary approvals.9 We could not confirm Mountainside’s rule for mandatory public-water or sewer connection for a new home; ask the health and engineering offices before choosing a private system.1211

Can you live in an RV or tiny home in Borough of Mountainside?

We could not confirm permission to occupy an RV, tiny home, manufactured home or accessory dwelling on a private Mountainside lot; ask the borough Engineering/Zoning Department about the intended use before buying a unit or relying on temporary accommodation during construction.11 A parking arrangement alone does not establish approval to use a vehicle as a dwelling; ask the zoning office separately about parking and residential occupancy.11

A proposed Mountainside dwelling remains subject to borough zoning and applicable construction permits.31 We could not confirm a Mountainside-specific minimum dwelling size or off-grid sanitation allowance; address those questions with Engineering/Zoning and the Health Department rather than assuming a small footprint removes approval requirements.1112

What are the steps to build a home in Borough of Mountainside?

  1. Confirm the Mountainside zoning district and layout with Engineering/Zoning; the zoning officer completes zoning review first.19
  2. Assemble the construction application, plans, plot plan, engineering release and other prior approvals; submit a grading plan if required.19
  3. Resolve water-supply and sewerage health certification before covered construction begins or the building permit is issued.5
  4. Complete zoning and engineering approval, then building, electrical, plumbing and fire subcode review; the stated review period can be up to 20 working days, with corrections resubmitted when needed.19
  5. Obtain the construction permit before regulated work, arrange required inspections, and apply for the certificate of occupancy after final inspections.12021

Mountainside’s zoning application fee is $50, non-refundable, and requires a current property survey; obtain the project’s construction-permit fees separately from the local enforcing agency.722

What stays with Union County when building in Borough of Mountainside?

Mountainside’s own Construction and Engineering/Zoning departments handle borough building permits and zoning review.211 Union County Planning Board reviews site plans and subdivisions as they affect county roads and drainage facilities, so a municipal project can also require county development review.23 Union County subdivision applications must be submitted for county review before local municipal approval, with county approval required where county roads or drainage facilities are affected.24

For land outside Mountainside, consult the Union County guide for the countywide pattern of municipal zoning and county development review.25 Before buying a Mountainside lot, ask Engineering/Zoning about access, grading, easements and the parcel’s building layout, then resolve private-water and septic approvals with the health authority.1995

Watch-outs

  • A Mountainside driveway, walkway or patio expansion needs zoning approval even when the material changes no other part of the project.10
  • Mountainside’s permission to draw plans for your own single-family dwelling is not an exemption from required building permits or zoning approval.8
  • Do not cover a Mountainside septic installation before health inspection and permission to cover under New Jersey law.18

Sources

  1. Building/Zoning/Engineering | Borough of Mountainside (Borough of Mountainside), quoted and re-checked
  2. Mountainside Construction Department (mountainside-nj.com)
  3. Building/Zoning/Engineering | Borough of Mountainside (Borough of Mountainside), quoted and re-checked
  4. Licenses | Borough of Mountainside (Borough of Mountainside), quoted and re-checked
  5. New Jersey Statutes, R.S. 58:11-23 through 58:11-43 (New Jersey statewide rule), quoted and re-checked
  6. Building/Zoning/Engineering | Borough of Mountainside (Borough of Mountainside), quoted and re-checked
  7. Building/Zoning/Engineering | Borough of Mountainside (Borough of Mountainside), quoted and re-checked
  8. Building/Zoning/Engineering | Borough of Mountainside (Borough of Mountainside), quoted and re-checked
  9. Bulletin 88-10: Private On-Site Water Supply Systems (New Jersey statewide rule), quoted and re-checked
  10. Building/Zoning/Engineering | Borough of Mountainside (Borough of Mountainside), quoted and re-checked
  11. Mountainside Engineering/Zoning Department (mountainside-nj.com)
  12. Mountainside Health Department (mountainside-nj.com)
  13. New Jersey Statutes, R.S. 58:11-23 through 58:11-43 (New Jersey statewide rule), quoted and re-checked
  14. Building/Zoning/Engineering | Borough of Mountainside (Borough of Mountainside), quoted and re-checked
  15. Building/Zoning/Engineering | Borough of Mountainside (Borough of Mountainside), quoted and re-checked
  16. Building/Zoning/Engineering | Borough of Mountainside (Borough of Mountainside), quoted and re-checked
  17. Building/Zoning/Engineering | Borough of Mountainside (Borough of Mountainside), quoted and re-checked
  18. New Jersey Statutes, R.S. 58:11-23 through 58:11-43 (New Jersey statewide rule), quoted and re-checked
  19. Building/Zoning/Engineering | Borough of Mountainside (Borough of Mountainside), quoted and re-checked
  20. Building/Zoning/Engineering | Borough of Mountainside (Borough of Mountainside), quoted and re-checked
  21. Building/Zoning/Engineering | Borough of Mountainside (Borough of Mountainside), quoted and re-checked
  22. New Jersey Uniform Construction Code, N.J.A.C. 5:23 (New Jersey statewide rule), quoted and re-checked
  23. Union County Planning Board (ucnj.org)
  24. Union County Planning Board, quoted and re-checked
  25. Bureaus of Planning and Transportation, quoted and re-checked

Written October 11, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.

Answers from the rulebook for Borough of Mountainside

Borough of Mountainside’s own rules

  • Building permitRequired

    Construction, enlargement, alteration, or demolition of structures inside Mountainside borough.

    • Ordinary repairs such as replacing gutters, interior trim in a one- or two-family dwelling, and repaving an existing driveway without changing size or lot coverage are listed as examples that do not require a permit.
    • Work without a permit may result in a fine of up to $2,000.

    maximum fine for work without permit: <= 2000 USD

    “A permit is generally required if an individual wishes to construct, enlarge, alter or demolish a structure.”
  • Owner-builder exemptionConditional

    Owner-applicants preparing drawings for their own single-family dwelling inside Mountainside borough.

    • The source describes permission to prepare drawings, not an exemption from permits or code compliance.
    • A New Jersey licensed architect or engineer is required for other drawings unless the applicant draws for the applicant's own single-family dwelling.
    • All required permits and approvals still apply.
    “These drawings may be done by the applicant for his own single-family dwelling or by a New Jersey licensed architect or engineer.”
  • InspectionsRequired

    Permitted building work inside Mountainside borough.

    • Required inspections include footings, reinforcement, foundations and walls, slabs, rough work, insulation, final work, and rated assemblies.
    • No building inspection will be made before required plumbing or electrical inspection approval.
    • Applicants must give 24 hours advance notice and call for final building, electrical, plumbing, and fire inspections.
    “After plans have been reviewed and accepted, and the appropriate permits have been issued, inspections are performed to insure that all construction is in accordance with the Uniform Construction Code of New Jersey and its adopted codes.”
  • Certificate of occupancyRequired

    Completed permitted projects and new commercial, office, warehouse, and industrial occupancies inside Mountainside borough.

    • The applicant must apply after final inspections.
    • Commercial uses require inspections from Fire, Building, Plumbing, and Fire Subcodes.
    • The borough states it does not perform certificate-of-occupancy inspections for sale of a home; it requires a different residential sale document.

    commercial certificate of occupancy fee: 241 USD

    “When the project is completed, the applicant must call for final building, electrical, plumbing, and fire inspections. The applicant must also apply for a certificate of occupancy.”
  • Local zoningPresent

    Mountainside borough zoning regulation and administration inside the borough.

    • The borough page states that permits must comply with the Borough Zoning Ordinance.
    • Zoning requirements vary by district.
    “The issuance of a permit indicates that plans for a project have been approved by Mountainside Borough officials and have complied with the Uniform Construction Code and Borough Zoning Ordinance.”
  • Minimum lot sizeSpecified

    One-family residential development in the R-2 district inside Mountainside borough.

    • The borough's zoning requirements page states a minimum lot area of 15,000 square feet for Residential 2.

    minimum lot area: >= 15000 square feet

    “Residential 2 Zoning / R-2 Calculation Sheet Minimum Lot Area | 15,000 Square Feet”
  • SetbacksSpecified

    One-family residential development in the R-1 district inside Mountainside borough.

    • Side setback is 10% of lot width or 10 feet minimum.

    front setback: 30 feet · rear setback: 30 feet · side setback: 10% of lot width or 10 ft. minimum

    “Front Yard Setback | 30 Ft. Rear Yard Setback | 30 Ft. Side Yard Setback | 10% of lot width or 10 ft. min”
    One more reviewed finding on this topic
    • Specified — One-family residential development in the R-2 district inside Mountainside borough.
      “Front Yard Setback | 30 Ft. Rear Yard Setback | 30 Ft. Side Yard Setback | 10% of lot width or 10 ft. min”
  • Lot coverageSpecified

    One-family residential development in the R-2 district inside Mountainside borough.

    • The stated maximum includes above-ground surfaces, driveways, walkways, patios, and other impermeable surfaces.

    maximum lot coverage: <= 30 percent of lot (above and driveways, walkway, patios, other impermeable surfaces) · maximum building footprint: <= 15 percent of lot area (foundation area)

    “Maximum Building Footprint (foundation area) | 15% of lot area Max. Ground Projections (porches, decks & roof overhangs) | 3.75% of lot Max. Lot Coverage (above & driveways, walkway, patios, other impermeable surfaces) | 30% of lot”
  • Building heightSpecified

    One-family residential development in the R-2 district inside Mountainside borough.

    maximum building height: <= 35 feet

    “Maximum Building Height | 35 Ft. Maximum Floor Area Ratio | .225 Maximum Building Footprint (foundation area) | 15% of lot area”
  • Septic permitRequired

    New, repair, or abandonment septic work inside Mountainside borough.

    • The borough page lists a permit category covering new, repair, and abandonment septic work.
    • The page does not provide the application form's technical standards or fees.
    “Septic System Permit (New, Repair, Abandon)”
  • Driveway accessRequired

    Expansion of an existing driveway, walkway, or patio inside Mountainside borough.

    • Any expansion, minor or otherwise, requires a zoning permit regardless of material.
    • Each applicable item requires a separate zoning permit application, $50 non-refundable fee, and current property survey.
    “Any Expansion (minor or otherwise) to an existing driveway, walkway, or patio, regardless of material used, requires a zoning permit.”
  • Permit feesPublished (with conditions)

    Published Mountainside borough fees for specified zoning, occupancy, and residential-sale inspections.

    • Zoning permit applications require a non-refundable $50 fee and current property survey.
    • Commercial certificates of occupancy require a $241 fee.
    • Smoke detector, carbon monoxide, and extinguisher inspection requests require a $100 fee.

    zoning permit fee: 50 USD (non-refundable) · commercial certificate of occupancy fee: 241 USD · smoke detector/resale inspection fee: 100 USD

    “Each application must be accompanied by a $50 fee (non-refundable) and must include a current property survey.”
  • Permit processPublished (with conditions)

    Construction permits inside Mountainside borough.

    • Required documentation includes the permit application, construction plans, plot plan, engineering release, prior approvals, and grading plan if required.
    • The zoning officer completes zoning review first; then documents undergo building, electrical, plumbing, and fire subcode review.
    • Review may take up to twenty working days; noncompliant documents must be corrected and resubmitted.

    maximum stated review period: <= 20 working days

    “After the Zoning and Engineering approval, the documents are reviewed by the building, electrical, plumbing, and fire subcode officials for completeness and code conformance. This process may take up to twenty working days.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Borough of Mountainside or Union County directly.

  • Minimum dwelling size — Minimum dwelling size inside Mountainside borough.
  • Camping on your land — Temporary camping inside Mountainside borough.
  • Tiny homes — Tiny-home occupancy inside Mountainside borough.
  • Manufactured homes — Manufactured-home occupancy inside Mountainside borough.
  • Accessory dwellings — Accessory-dwelling occupancy inside Mountainside borough.
7 more unanswered
  • Septic inspection
  • Off-grid sanitation
  • Well permit
  • Mandatory utility hookup
  • Agricultural exemption
  • Subdividing land
  • Short-term rentals

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.

Unanswered questions are usually a sign that Borough of Mountainside publishes no rule on the point, not that none exists. Union County’s page lists the county offices to call.

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