Bolthole Index

Morris County, New Jersey

Zoning, building permits and septic rules in Mountain Lakes, New Jersey

The Borough of Mountain Lakes, in Morris County, New Jersey, requires a construction permit from its Construction Official before a building or structure is erected, altered or demolished1. The borough adopts and administers its own zoning ordinance2, and a zoning permit must be issued before a building permit3. Septic permits come from the borough Board of Health4.

At a glance

Building permit
Required; issued by the borough Construction Official1
Zoning
Borough Land Use and Zoning Ordinance; zoning permit before a building permit23
Septic permit
Issued by the borough Board of Health4
Certificate of occupancy
Required before land or a structure is occupied or used5
Accessory apartments
Affordable accessory apartments allowed in residential zones, subject to Article XVIII6

Who to call

Building permits

Borough of Mountain Lakes Construction Office

Construction permits, code enforcement and zoning approvals inside Mountain Lakes

973-334-3131

400 Boulevard

Septic permits

Borough of Mountain Lakes Health Office (Board of Health)

Borough health office; the Board of Health issues septic system permits inside Mountain Lakes

973-334-3131

400 Boulevard

Contact details are copied from each office’s official page and were checked against it on October 13, 2026.

Off-grid gear

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

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Does Mountain Lakes, NJ have zoning, and what does it mean for RVs, tiny homes and lot size?

Yes. The Borough of Mountain Lakes adopts and administers its own Land Use and Zoning Ordinance, enforced by the Construction Official, Code Enforcement Official, Zoning Officer or another officer the Borough Manager designates2. Morris County does not zone; New Jersey gives zoning authority to municipalities7.

Lot size, setbacks, height and coverage are set district by district under state law, so the answer depends on the zoning district of the parcel89. We could not confirm a minimum dwelling size, and we could not confirm any rule on living in an RV, camping, tiny homes or manufactured homes inside the borough; ask the Construction Office at 973-334-3131 before you plan any of those10.

Affordable accessory apartments are listed as permitted accessory uses in the residential zones, subject to Article XVIII of the ordinance6.

Do you need a building permit in Mountain Lakes, and who issues it?

Yes. In Mountain Lakes, no building or structure may be erected, moved, extended, enlarged, altered or demolished until the Construction Official grants a permit1. The permit is conditional until a foundation survey is made once the foundation is in place1.

A zoning permit certifying that the request conforms to the zoning chapter is issued before the building permit3. The borough's Construction Office states that zoning approvals are required for additions, changes of use and some alterations10.

New Jersey's Uniform Construction Code applies statewide and is enforced locally by municipal construction officials11. Morris County does not issue building permits12. A homeowner may sign as the owner-occupant when doing the work on an owner-occupied home13; we could not confirm a borough-specific owner-builder rule, so ask the Construction Office.

How do septic permits work in Mountain Lakes?

Inside Mountain Lakes, no one may locate, construct or alter an individual sewage disposal system until the Board of Health issues a permit4. This is a borough permit, not a Morris County Division of Public Health permit.

The borough requires a final inspection by the Health Officer, to be made within 48 hours of notice, excluding weekends and holidays, and the applicant must give notice before any underground portions are covered14. Where no public or private sewer is available, a house connects to a septic tank or other individual facility; a direct sewer connection is required when one becomes available15.

State law bars a building permit until the board of health certifies the water supply and sewerage facilities16. About 12% of the soils in Morris County rate as not limited for a conventional drain field, so expect a site evaluation and possibly an engineered system17.

Building a home in Mountain Lakes: the steps, in order

  1. Confirm the zoning district and ask the Construction Office what applies to your parcel10.
  2. Get the septic or sewer approval from the borough Board of Health, because state law requires it before a building permit16.
  3. Obtain a zoning permit certifying conformity with the zoning chapter3.
  4. If you are subdividing or the project needs site-plan review, get Planning Board approval first; a single-family home has exceptions from site-plan review18.
  5. Apply for the construction permit from the Construction Official1.
  6. Have required inspections made at footing, rough plumbing and electrical, and framing stages19.
  7. Obtain the certificate of occupancy before using the structure5.

What stays with Morris County and the state, and what to check before you buy?

Morris County does not issue building permits or zoning inside the borough12. County-level items are subdivision applications that front on county roads20 and work in a county right-of-way, which needs a County Engineering Division permit21. A driveway onto a state highway needs a state access permit22.

For the rest of Morris County outside the borough, see the Morris County page.

Before you buy, check floodplain and drainage rules and driveway access with the Construction Office; we could not confirm a complete borough rule on either. Morris County's effective property tax rate is 1.8%23.

Watch-outs

  • We could not confirm borough rules on RV living, temporary camping, tiny homes, manufactured homes, minimum dwelling size or short-term rentals; ask the Construction Office at 973-334-313110.
  • The borough's well permit rule is unconfirmed; state law has municipal or county health officials issue well construction permits24.
  • A new owner-built home still needs a certificate of occupancy, and the owner must file an affidavit with the construction official25.

Sources

  1. Article VII: Permits and Certificates (Borough of Mountain Lakes), quoted and re-checked
  2. ecode360.com (Borough of Mountain Lakes), quoted and re-checked
  3. Article VII: Permits and Certificates (Borough of Mountain Lakes), quoted and re-checked
  4. Chapter 290: Sewage Disposal Systems, Individual (Borough of Mountain Lakes), quoted and re-checked
  5. Article VII: Permits and Certificates (Borough of Mountain Lakes), quoted and re-checked
  6. Article X: Zoning District Regulations (Borough of Mountain Lakes), quoted and re-checked
  7. P.L. 2013, c.106 — Municipal Land Use Law amendments (New Jersey statewide rule), quoted and re-checked
  8. P.L. 2013, c.106 (Municipal Land Use Law amendments) (New Jersey statewide rule), quoted and re-checked
  9. P.L. 2013, c.106 (Municipal Land Use Law amendments) (New Jersey statewide rule), quoted and re-checked
  10. Borough of Mountain Lakes Construction Office (mountainlakes.gov)
  11. Bureau of Construction Project Review, quoted and re-checked
  12. Town of Morristown - Division of Building and Uniform Construction Code (2026 county census)
  13. nj.gov, quoted and re-checked
  14. ecode360.com (Borough of Mountain Lakes), quoted and re-checked
  15. Chapter 191: Sewers (Borough of Mountain Lakes), quoted and re-checked
  16. New Jersey Statutes, R.S. 58:11-23 through 58:11-43 (New Jersey statewide rule), quoted and re-checked
  17. Share of soils USDA rates "not limited" for a conventional septic drain field (SSURGO). A strict rating: the median county is about 6% and a tenth of counties are 0%, so a low figure means most lots need a site evaluation or an engineered system, not that septic is impossible. Cite it only with that caveat: Bolthole Index county data
  18. Article VIII: Subdivision of Land and Site Plan Review (Borough of Mountain Lakes), quoted and re-checked
  19. New Jersey Department of Community Affairs, New Home Warranty—Consumer Information (New Jersey statewide rule), quoted and re-checked
  20. Land Development Review, quoted and re-checked
  21. Morris County Land Development Standards, quoted and re-checked
  22. Major Access Permits (New Jersey statewide rule), quoted and re-checked
  23. Effective property tax rate: Bolthole Index county data
  24. Bulletin 88-10: Private On-Site Water Supply Systems (New Jersey statewide rule), quoted and re-checked
  25. N.J.A.C. 5:23, Uniform Construction Code (New Jersey statewide rule), quoted and re-checked

Written October 13, 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 Mountain Lakes

Borough of Mountain Lakes’s own rules

  • Building permitRequired

    Erection, movement, extension, enlargement, alteration, or demolition of a building or structure inside Mountain Lakes borough.

    • A construction permit is conditional until a foundation survey is made when the foundation is in place.
    • The survey must be sealed by a licensed surveyor and show foundation dimensions, property-line distances, and top-of-foundation elevation.
    • The Construction Official may waive the survey if satisfied that the foundation meets setback requirements.
    “No building, structure or part thereof shall be erected, raised, moved, extended, enlarged, altered or demolished until a permit has been granted by the Construction Official. A construction permit shall be conditional until a foundation survey is made at the time the foundation is in place.”
  • Certificate of occupancyRequired

    Occupancy or use of land or a structure inside Mountain Lakes borough, including changes of use.

    • A new certificate of occupancy is required for a change of use of land or structure.
    • The certificate must state that the specified use and building comply with the applicable chapters.
    “No land or structure shall be occupied or used in whole or in part for any purpose until a certificate of occupancy shall have been issued by the Construction Official stating that the use and building therein specified, or either of them as the case may be, complies with all the provisions of these chapters. A new certificate of occupancy shall be required for a change of use of land or structure.”
  • Local zoningPresent

    Land inside Mountain Lakes borough; the Borough adopts and administers its own Land Use and Zoning Ordinance.

    • The ordinance is administered by the Borough Planning Board and enforced by the Construction Official, Code Enforcement Official, Zoning Officer, or another officer designated by the Borough Manager.
    “This chapter shall be known and may be cited as the "Land Use and Zoning Ordinance" of the Borough of Mountain Lakes.”
  • Accessory dwellingsAllowed (with conditions)

    Affordable accessory apartments in residential zones inside Mountain Lakes borough.

    • Affordable accessory apartments are listed as permitted accessory uses in the residential zones.
    • The use remains subject to Article XVIII and applicable zoning, building, water, sewer, parking, and affordability requirements.
    “Affordable accessory apartments in accordance with Article XVIII of this chapter.”
  • Who permits septicLocal

    Individual sewage-disposal systems inside Mountain Lakes borough; the Borough Board of Health is the permitting authority.

    • The municipal code adopts NJDEP standards and preserves additional requirements of the Borough Health Officer, Board of Health, or another regulatory body with jurisdiction.
    “No person shall locate, construct or alter any individual sewage disposal system until a permit for the location, construction or alteration of a sewage disposal system shall have been issued by the Board of Health.”
  • Septic inspectionRequired

    Individual sewage-disposal facilities inside Mountain Lakes borough.

    • The Health Officer may inspect at any stage.
    • The applicant must notify the Health Officer when ready for final inspection and before underground portions are covered.
    • The inspection is to be made within 48 hours, excluding Saturdays, Sundays, and legal holidays, after notice.

    inspection deadline: <= 48 hours (Saturdays, Sundays, and legal holidays excluded)

    “A permit for an individual sewage disposal facility shall not become effective until the installation is completed to the satisfaction of the Health Officer. He shall be allowed to inspect the work at any stage of construction, and, in any event, the applicant for the permit shall notify the Health Officer, or such other person designated by the Manager, when the work is ready for final inspection and before any underground portions are covered. The inspection shall be made within 48 hours, excluding Saturdays, Sundays and legal holidays, of the receipt of such notice by the Health Officer.”
  • Off-grid sanitationLimited

    On-site sanitation inside Mountain Lakes borough where public or private sewer is unavailable.

    • The property must use a septic tank or other individual sewage-disposal facility complying with the municipal chapter and applicable health codes.
    • An individual-system permit and inspection are required.
    • Direct connection to a public sewer is required when one becomes available.
    “Where a public or private sewer system is not available under the provision of Subsection B, the house service connection shall be connected to a septic tank or other individual sewage disposal facility complying with the provisions of this section.”
  • Subdividing landRegulated (with conditions)

    Subdivision and site-plan development inside Mountain Lakes borough.

    • All necessary permits and approvals must be obtained before a construction permit may be issued and before construction may commence.
    • Site-plan review has exceptions for a single-family home and a municipal capital improvement project.
    • A change to an approved site plan requires Planning Board or Zoning Board of Adjustment approval and a new certificate of occupancy.
    “The purpose of this article shall be to provide rules, regulations and standards to guide land subdivision and site development in the Borough.”
  • Permit processPartial

    Development and construction-permit processing inside Mountain Lakes borough.

    • A zoning permit is required before covered construction, reconstruction, demolition, alteration, conversion, installation, commencement of use, or change of use.
    • A zoning permit certifying conformity is required before issuance of a building permit.
    • All necessary permits and approvals must be obtained before construction may commence.
    “Prior to the issuance of a building permit, a zoning permit certifying that the request conforms with the provisions of this chapter shall be issued.”

Still unanswered

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

  • Owner-builder exemption — Owner-builder exemptions from construction-permit requirements inside Mountain Lakes borough.
  • Building code adopted — Building-code adoption for construction inside Mountain Lakes borough.
  • Inspections — Building inspections inside Mountain Lakes borough.
  • Minimum dwelling size — Minimum dwelling size in the principal single-family residential districts.
  • Living in an RV — Residential occupancy of recreational vehicles inside Mountain Lakes borough.
8 more unanswered
  • Camping on your land
  • Tiny homes
  • Manufactured homes
  • Well permit
  • Agricultural exemption
  • Driveway access
  • Building in a floodplain
  • 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 Mountain Lakes publishes no rule on the point, not that none exists. Morris County’s page lists the county offices to call.

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