Skip to main content
CityRuleLookup
Key FactsOrdinance TextFull BreakdownViolationsFAQSourcesMore in Plainfield

Plainfield, NJ Accessory Structures: ADU Owner Occupancy (2026)

Significant Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified October 2026

Key Facts

Occupancy rule
Primary dwelling or ADU must be owner-occupied
Separate sale
ADUs may not be sold separately from the primary dwelling
Districts
R-1, R-2 and R-3
Application proof
Site plans, building plans and proof of ownership
Approver
Zoning Officer, administrative review
Amended
February 10, 2025 and May 12, 2025

Summary

In the City of Plainfield, New Jersey, § 17:9-23(C) requires that either the primary dwelling or the accessory dwelling unit be owner-occupied, and it bars selling an ADU separately from the primary dwelling. The rule attaches to every ADU permitted in the R-1, R-2 and R-3 districts.

§ 17:9-23. Buildings or structures per lot - Primary and Accessory Dwelling Units. ... 1. Primary Dwelling Unit: The principal residential structure on a lot or parcel. No lot in a residential zone district shall contain more than one (1) principal building or structure. ... C. Occupancy. 1. Either the primary dwelling or the ADU must be owner-occupied. 2. ADUs may not be sold separately from the primary dwelling.

View official code

Full Breakdown

Subsection C of § 17:9-23 puts two conditions on occupancy. The section was amended on February 10, 2025 by Ordinance MC 2025-06 and again on May 12, 2025 by Ordinance MC 2025-17. First, either the primary dwelling or the ADU must be owner-occupied. The printed wording leaves the owner free to live in either unit, but one of the two has to be the owner's residence. Second, ADUs may not be sold separately from the primary dwelling, so the ADU stays with the main house instead of becoming a lot of its own.

The condition sits inside a larger structure. The section defines the Primary Dwelling Unit as the principal residential structure on a lot or parcel and adds that no lot in a residential zone district contains more than one principal building or structure. ADUs are permitted only in R-1, R-2 and R-3. The owner applies for a development permit with the Zoning Officer, and the application must include site plans, building plans and proof of ownership, which is where the owner status first gets documented. Approval is by administrative review by the Zoning Officer.

As printed, § 17:9-23 does not define the term owner-occupied and does not set an annual certification step. Two neighboring provisions carry similar ideas for other uses. Under § 17:9-22(G), the owner of a bed and breakfast guesthouse or homestay must maintain primary residence in the on-site principal structure. Under § 17:9-19(H), no garage, apartment over a garage or apartment over an accessory structure is allowed as a principal residence.

Violations & Fines

Section 17:9-23 prints no fine of its own. Under § 17:1-22, the City Council, the Zoning Officer or another proper official can start legal action to restrain or correct a violation of Chapter 17, and each day the violation continues after notice and a reasonable opportunity to correct counts as a separate violation. Section 17:1-23 sets the penalty at not more than $1,500 for the first ten days after the initial summons and not more than $75 per day after that.

Frequently Asked Questions

Can I rent out both the house and the ADU in Plainfield?
Not under § 17:9-23(C)(1), which says either the primary dwelling or the ADU must be owner-occupied. The code does not say which unit the owner lives in, only that one of the two is the owner's. A landlord who lives elsewhere and rents both units does not meet the rule as printed.
Can I sell the ADU separately from the main house?
No. Subsection C(2) says ADUs may not be sold separately from the primary dwelling. The ADU and the primary dwelling on the lot move together, which also fits the section's definition of a primary dwelling as the principal residential structure on the lot or parcel.
What proof of ownership does the application need?
The application to the Zoning Officer must include site plans, building plans and proof of ownership under § 17:9-23(H)(2). The section does not list which documents count as proof, so the Zoning Officer, who reviews and approves ADUs administratively, decides what satisfies that requirement.
Is there a similar owner-residence rule for other uses in Plainfield?
Yes, for bed and breakfast guesthouses and homestays. Section 17:9-22(G) says the owner of the premises must maintain primary residence in the on-site principal structure. That rule is separate from the ADU rule, and it applies in the residential historic zones where bed and breakfast uses are permitted.

Sources & Official References

Other rules in Plainfield

ADU RulesSome RestrictionsShed & Carport RulesSome RestrictionsParking Rules: RV & Boat ParkingSome RestrictionsParking Rules: Driveway RulesSome RestrictionsParking Rules: EV ChargingSome RestrictionsParking Rules: Loading ZonesSome RestrictionsParking Rules: Snow Removal Parking RulesSome RestrictionsParking Rules: Commercial & Oversized VehiclesHeavy Restrictions

All Plainfield rules

Compare Plainfield to another location·View the New Jersey accessory structures overview

Get notified when ADU Owner Occupancy in Plainfield, NJ changes

We'll email you the moment we detect a change in the code. No spam, unsubscribe anytime.

We'll never sell or share your email. One-click unsubscribe in every email.

See something wrong?

Help us keep this page accurate. If you notice an error or outdated information, let us know.