Bolthole Index

Mercer County, New Jersey

Zoning, building permits and septic rules in Hopewell Borough, New Jersey

Building in Hopewell Borough, New Jersey (Mercer County) takes two permits: a zoning permit from the borough's Zoning Officer1 and a construction permit under the state Uniform Construction Code2. Hopewell sets its own zoning districts in Chapter 12 of the borough code3. Septic approval comes from a board of health, not the county; we could not confirm which office covers septic inside the borough4.

At a glance

Building permit
Required; construction permit under the NJ Uniform Construction Code2
Zoning
Yes, borough zoning districts under Chapter 12 of the borough code3
Zoning permit
Required before the construction permit for building, erecting or altering a structure1
Septic
Local board of health approval, required before a building permit; borough-specific office unconfirmed5
Certificate of occupancy
Required before a permitted building is occupied or used6
Owner-builder
Allowed for personal use with an affidavit; permits and inspections still apply7
RV or tiny home living
Not confirmed; ask the Zoning Officer1

Who to call

Building permits

Hopewell Borough Building Department (Construction Official)

Construction permits, plan review, inspections and certificates of occupancy under the NJ Uniform Construction Code inside Hopewell Borough.

(609) 567-3653

Zoning

Hopewell Borough Zoning Officer

Zoning permits and zoning-ordinance compliance review inside Hopewell Borough.

(609) 466-2636, ext. 107

88 East Broad Street, Hopewell, NJ 08525

Septic permits

Hopewell Township Health Department (serves Hopewell Borough)

Public health services for the borough under a shared services agreement; ask this office who reviews septic and well plans for a borough lot.

609-737-0120

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 Hopewell means bringing your own water and power. The kit we’d start with:

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Do you need a building permit in Hopewell Borough, New Jersey?

Yes. New Jersey's Uniform Construction Code requires a construction permit for new construction and for enlarging, repairing, altering or demolishing a structure; ordinary maintenance is excepted2. Hopewell Borough adds a step in front: a zoning permit from the Zoning Officer must be in place before the Construction Official can issue the construction permit1. Heating/cooling, plumbing, electrical and new siding work do not need a zoning permit1.

Once a complete application is filed, the local enforcing agency must approve or deny it within 20 business days2. The borough's building permit applies to land inside the borough only; Mercer County does not issue residential building permits8.

Who issues building permits in Hopewell Borough, and how do you reach them?

Hopewell Borough uses the New Jersey Department of Community Affairs as its building department, and the office issues permits for all construction activity in the borough9. The Construction Official can be reached at (609) 567-36539. Inspection requests go through the state's online portal with the permit number in hand9.

For zoning, the Zoning Officer is at Borough Hall, 88 East Broad Street, (609) 466-2636, ext. 1071. Fees are not set by the county: municipalities adopt their own fee schedules by ordinance, so ask the Construction Official for the current schedule10. The state caps plan review at 5 to 25 percent of the construction-permit fee11.

Does Hopewell Borough have zoning, and what does it mean for RVs, tiny homes and lot size?

Yes. Hopewell Borough is divided into zones by Chapter 12 of the borough code, with a zoning map and district-specific standards3. Lot size, setbacks, coverage and height all depend on the zone, so look up the parcel first; the Zoning Officer's office maintains a zoning lookup and map1. Zoning also covers the Historic District, Buffer Zone and floodplain overlays, which the Zoning Officer can confirm for a given property1.

Accessory apartments are permitted only in the R-75, R-75P and R-100 zones, inside an existing single-family dwelling or accessory building, and for a low- or moderate-income household; the minimum size is 350 square feet12. We could not confirm any borough rule on living in an RV, tiny-home occupancy or temporary camping; ask the Zoning Officer before planning on any of them1.

How do septic permits work in Hopewell Borough?

In New Jersey, no building permit may issue until the board of health having jurisdiction certifies that the water supply and sewerage facilities comply with state and local standards5. Septic systems must also be inspected by the board of health's representative before they are covered13. Municipal or county boards of health enforce these rules, not the building department4.

Hopewell Borough's own board of health is volunteer-run, and public health services for the borough come from the Hopewell Township Health Department under a shared services agreement14. We could not confirm which office reviews septic plans for a borough lot or whether the lot connects to public sewer; call the health department at 609-737-0120 before you buy14.

What are the steps to build a home in Hopewell Borough, in order?

  1. Look up the parcel's zone and overlays with the Zoning Officer1.
  2. Get septic and well questions answered by the health department; the board of health must certify before a building permit issues5.
  3. Obtain the zoning permit; it must be in place before the construction permit1.
  4. Apply to the Construction Official for the construction permit9.
  5. Request inspections as work proceeds, including footing, rough plumbing and electrical, and framing stages15.
  6. Obtain a certificate of occupancy before the building is occupied or used6.

An owner who builds a new home must file an affidavit with the construction official before a certificate of occupancy issues7.

What stays with Mercer County, and what should you check before buying in Hopewell Borough?

Mercer County does not zone and does not issue residential building permits; the borough does both for land inside its limits16. A driveway onto a state highway needs a state access permit17; ask Mercer County about driveways onto county roads. For land outside the borough, see the Mercer County page.

The figures below are county-level. Mercer County's effective property tax rate is 2.5%18, and the median bill is $8,804 a year19. A typical home value is $453,31720. About 11% of county soils rate as not limited for a conventional septic drain field21, so expect a site evaluation.

Watch-outs

  • Searches for Hopewell often return Hopewell Township, a separate municipality with its own construction, zoning and health offices; the borough's offices are at Borough Hall, 88 East Broad Street1.
  • We could not confirm a borough rule on RV occupancy, tiny homes, wells or driveways; ask the Zoning Officer and the health department before you buy1.
  • A zoning permit and a construction permit are separate approvals, and the construction permit will not issue without the zoning permit1.
  • An owner-built home still needs permits and inspections; the owner affidavit only covers certificate-of-occupancy and warranty coverage7.

Sources

  1. Hopewell Borough Zoning Officer (hopewellboroughnj.gov)
  2. The New Jersey State Uniform Construction Code, quoted and re-checked
  3. Chapter 12 Zoning, Borough of Hopewell (Borough of Hopewell), quoted and re-checked
  4. Bulletin 79-7: Septic Systems, 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. Chapter 12 Zoning, Borough of Hopewell (Borough of Hopewell), quoted and re-checked
  7. N.J.A.C. 5:23, Uniform Construction Code (New Jersey statewide rule), quoted and re-checked
  8. P.L. 2018, c.157 — County Code Enforcement Pilot Program (New Jersey statewide rule), quoted and re-checked
  9. Hopewell Borough Building Department (Construction Official) (hopewellboroughnj.gov)
  10. The New Jersey State Uniform Construction Code, quoted and re-checked
  11. New Jersey Uniform Construction Code, N.J.A.C. 5:23 (New Jersey statewide rule), quoted and re-checked
  12. Chapter 12 Zoning, Borough of Hopewell (Borough of Hopewell), quoted and re-checked
  13. New Jersey Statutes, R.S. 58:11-23 through 58:11-43 (New Jersey statewide rule), quoted and re-checked
  14. Hopewell Township Health Department (serves Hopewell Borough) (hopewellboroughnj.gov)
  15. New Jersey Department of Community Affairs, New Home Warranty—Consumer Information (New Jersey statewide rule), quoted and re-checked
  16. P.L. 2013, c.106 — Municipal Land Use Law amendments (New Jersey statewide rule), quoted and re-checked
  17. Major Access Permits (New Jersey statewide rule), quoted and re-checked
  18. Effective property tax rate: Bolthole Index county data
  19. Median property tax bill: Bolthole Index county data
  20. Typical home value (Zillow): Bolthole Index county data
  21. 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

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 Hopewell

Borough of Hopewell’s own rules

  • Certificate of occupancyRequired

    Any building or structure inside Hopewell borough for which a building permit has been issued, before it is occupied or used.

    • Commercial or multiple-family buildings require a certificate for each separate store, office, or family unit.
    • A new certificate is required for further use of land, building, or structure.
    • An approved as-built plan must be submitted before issuance.
    • The certificate becomes invalid on the tenth calendar day after notice of a zoning violation.

    violation invalidation period: 10 calendar days (Following the zoning officer's notice of violation.)

    “A certificate of occupancy shall be obtained from the building inspector by the owner or his duly authorized agent before any building or structure for which a building permit has been issued is occupied or used.”
  • Local zoningPresent

    Land inside Hopewell borough; Borough Code Chapter 12 establishes and administers zoning districts and regulations.

    • The code includes a zoning map and district-specific standards.
    “For the purposes of this chapter, the borough is hereby divided into the following zones:”
  • Accessory dwellingsLimited

    Accessory apartments in the R-75, R-75P, and R-100 zones inside Hopewell borough.

    • The unit must be within an existing single-family detached dwelling or an accessory building to one.
    • The unit must be occupied by a low- or moderate-income household under the cited COAH rules.
    • Minimum gross floor area is 350 square feet.
    • The unit must include living-sleeping space, cooking facilities, a kitchen sink, and a complete sanitary facility.
    • The unit must have at least two rooms, one a full bathroom, and no more than two bedrooms.
    • At least one additional off-street parking space is required.

    minimum gross floor area: >= 350 square feet · maximum bedrooms: <= 2 bedrooms · additional parking: >= 1 space (In addition to the two required for the existing principal dwelling.)

    “Accessory apartments are permitted in the R-75, R-75P, and R-100 zones if, in addition to the requirements of this paragraph, all other requirements of the applicable zone district are met.”
  • Permit processPartial

    Development and construction permitting inside Hopewell borough.

    • Obtain a zoning permit before construction, erection, alteration, or change in use.
    • Obtain borough engineer approval of an individual drainage plan and survey before construction unless previously approved through subdivision or site-plan review.
    • Obtain a building permit and post it until certificate of occupancy.
    • Obtain a certificate of occupancy before use or occupancy.
    • The opened materials did not provide the complete application forms or all numeric fees.
    “Prior to the construction, erection, or alteration of any structure, or upon any change in the use of land, building or structure, the owner or his duly authorized agent shall secure a zoning permit from the zoning officer.”

Rules another office applies inside Borough of Hopewell

Borough of Hopewell does not set these itself; the county, a health district or the state does, and they apply to every address inside its limits.

  • InspectionsRequired

    Construction projects inside Hopewell borough subject to the New Jersey Uniform Construction Code.

    • Inspections are periodic and occur at specified construction stages; inspectors are not required to remain on site continuously.
    • The state page identifies footing, rough plumbing/electrical, and framing inspections as examples.
    “Rather, the UCC requires that inspectors carry out periodic inspections during the progress of work to ensure that the work inspected conforms to the UCC.”

Still unanswered

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

  • Owner-builder exemption — Owner-builder exemption from building-permit or code requirements inside Hopewell borough.
  • Living in an RV — Occupancy of recreational vehicles on private land inside Hopewell borough.
  • Camping on your land — Temporary camping on private land inside Hopewell borough.
  • Tiny homes — Tiny-home occupancy inside Hopewell borough.
  • Manufactured homes — Manufactured-home occupancy inside Hopewell borough.
8 more unanswered
  • Who permits septic
  • Septic permit
  • Septic inspection
  • Off-grid sanitation
  • Well permit
  • Mandatory utility hookup
  • Driveway access
  • 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 Hopewell publishes no rule on the point, not that none exists. Mercer County’s page lists the county offices to call.

← All of Mercer County: county rules, score and offices