The short answer
A preliminary site plan is the first complete layout of a project: buildings, lots or pads, internal drives, parking, open space and the yield, drawn to test what fits and to put the program in front of the jurisdiction at the concept, sketch or preliminary stage. A final site plan is the set the approval and the construction permits rest on: the same layout carried into grading, drainage, stormwater, utilities, the boundary survey and the building sheets, with each part sealed by the professional of record. New Jersey's Municipal Land Use Law treats them as two approvals with separate clocks: a board must act on a preliminary site plan within 45 days (10 acres or less and 10 units or less) or 95 days, and on a final site plan within 45 days, or the plan is approved by default [1].
| Preliminary site plan | Final site plan | |
|---|---|---|
| Purpose | Settle the use, layout, access and yield before engineering | Fix the approved design for construction permits or recording |
| Level of detail | Buildings, circulation, parking, pads or lots, site data table | Grading, drainage, stormwater, utilities, survey, building sheets |
| Who prepares | In New Jersey, drives, parking and circulation may be prepared by "an architect, planner, engineer, or licensed landscape architect" [2] | A professional engineer for the engineering, a land surveyor for the survey, an architect for the building sheets [2] |
| Seal | Set by the state rule and the local code; many cities and counties accept an unsealed plan at the concept or pre-application stage | Where the work is engineering, surveying or architecture, yes; in Alaska a registrant who issues final drawings stamps and signs them [3] |
| Review stage | Pre-application, concept, sketch, exploratory, preliminary | Final site plan, final plat, record plan, construction drawings |
What "preliminary" means in the seal rules
The professional rules draw the same line the review process does. Maine requires an engineer's seal on engineering plans formally filed with a public body, released for construction or submitted to contractors for bids, and none on documents clearly identified as "PRELIMINARY," "PROGRESS" or the like [4]. Washington separates "final documents," which carry the seal, signature and date of the licensee "who prepared or directly supervised the work," from "preliminary documents," which are stamped but need not be signed or dated [5]. In both states the seal attaches when a document is filed with a public body or released for construction, not while the layout is still being tested.
| Rule | Preliminary or draft documents | Final documents |
|---|---|---|
| Maine, 02-322 CMR Chapter 2, section 11 | No engineer's seal when clearly marked PRELIMINARY or PROGRESS [4] | Seal when filed with a public body, released for construction or put out to bid [4] |
| Washington, WAC 196-23-020 | Stamped; signature and date not required [5] | Seal, signature and date of the licensee who prepared or directly supervised the work [5] |
| Rhode Island, 430-RICR-00-00-1.7 | Interim and draft sheets identified as such [6] | Seal on final cover sheets and each original sheet, with signature and date [6] |
| Iowa, 193C-6.1(4) | Non-final submissions labeled "preliminary" or "draft" [7] | Engineering and surveying documents carry the licensee's signature, certification and Iowa seal [8] |
| Alaska, AS 08.48.221 | Not stated | Stamped and signed when final drawings are issued [3] |
| NCEES Model Rules, 240.20A | Unsealed preliminary documents permitted if marked "PRELIMINARY, NOT FOR CONSTRUCTION, RECORDING PURPOSES, OR IMPLEMENTATION" [9] | Not stated |
New Jersey applies its division of professional work to both stages. The board rule says the elements "of a preliminary or final site plan or major subdivision plat shall be within the professional scope of the various professions" (N.J.A.C. 13:40-7.1); no municipal or county ordinance may reduce or expand those scopes (N.J.A.C. 13:27-7.5), and informal site plans that no ordinance requires fall outside the rule [2]. For a preliminary site plan, preliminary architectural plans and elevations are sufficient (N.J.S.A. 40:55D-46) [1]. The building does not have to be designed to construction detail before the site plan is heard.
The stage names counties and cities use
Stage names change from one code to the next, and so does the point where a seal is first required. Some codes open with a concept or sketch step, some make the preliminary plan the first formal filing, and a few want a sealed or certified plan at the first site plan submission. "Not stated" below means the stage is documented but its seal rule is not; the submittal checklist for that stage settles it.
| Jurisdiction | Stage names, in order | Seal at the early stage |
|---|---|---|
| Baltimore County, MD | Pre-Concept Plan Conference, Concept Plan, Concept Plan Conference, Community Input Meeting, Development Plan, Development Plan Conference, Development Plan Hearing [10] | Not stated |
| Montgomery County, MD | Pre-preliminary submissions, sketch or project plans, preliminary and administrative subdivision plans, site plans, record plats [11] | Not stated |
| Anne Arundel County, MD | Sketch Plan (Article 17-3-201), then Final Plan (Article 17-3-301); site development without subdivision starts with a Preliminary Plan [12] | Not stated |
| Carroll County, MD | Concept plan before the Technical Review Committee and the Planning and Zoning Commission, then the site plan [13] | Not stated |
| Howard County, MD | Site Development Plan [14] | Yes: a Maryland registered engineer or architect must prepare the plans [14] |
| New Castle County, DE | Pre-application sketch (§40.31.112), exploratory (§40.31.113), preliminary, record plan (§40.31.114) [15] | Not stated; a digital CAD file (DWG or DXF) is due at the exploratory stage [15] |
| Sussex County, DE | Site plan submission [16] | Yes: seal and signature of a registered Delaware land surveyor or professional engineer [16] |
| Providence, RI | Pre-application, then master plan, preliminary and final stages for major land development [17] | Not stated |
| Cedar Rapids, IA | Administrative Site Development Plan, or a Preliminary Site Development Plan where the site adjoins residential zoning or planned residential use [18] | Yes: "certified by a registered civil engineer licensed in the State of Iowa" [18] |
| New Jersey municipalities | Preliminary site plan, then final site plan [1] | Engineering sheets sealed by a professional engineer; drives, parking and circulation by an architect, planner, engineer or landscape architect [2] |
| Jefferson County, TX (RV parks) | Preliminary Site Plan, then construction plans (Appendix 7, 2023) [19] | Not stated |
| Florida health review (RV parks) | Plans drawn to scale for new parks; drawings for existing parks and consolidations [20] | Existing-park drawings "do not have to be drawn to scale or completed by an engineer" if dimensions are shown [20] |
| Vermont towns (24 V.S.A. Chapter 117) | Site plan review before the Development Review Board or Planning Commission [21] | No seal required by the statute for a purely local site plan [21] |
| Hattiesburg, MS | Site plan review application [22] | Drawn to scale by a design professional or to a recognized graphic standard [22] |
| Williston, ND | Mandatory pre-application meeting with a planner [23]; site plan with the building permit [24] | No: professionally drafted plans encouraged but not required [24] |
Three patterns run through these examples. Concept and sketch steps can be advisory: Chester County, Pennsylvania notes that a planning commission "does not rule upon sketch plans" [25], while O'Fallon, Illinois merges the two terms in a "Preliminary site plan (concept plan)," the plan "required to depict conceptual development plans for purposes of approval of a planned or special use" [26]. The preliminary plan is the first formal filing in several of these codes, including New Jersey's preliminary site plan and Anne Arundel County's Preliminary Plan for site development [1, 12]. And a seal can be required at the first filing: Sussex County and Cedar Rapids require a sealed or certified site plan, and Howard County requires a Maryland registered engineer or architect to prepare the Site Development Plan [14, 16, 18].
What the preliminary plan carries, and what comes after it
A preliminary site plan carries the layout and the numbers: site disposition, buildings and, where the program needs them, rooms and floor plans, amenities, internal roads and drive aisles, parking, pads, sites or units, and the yield, organized with a site data table (acreage, zoning, density against the cap, setbacks, parking required against provided, unit mix). It is the sheet a developer takes to a concept or pre-application meeting, gives a lender, gives a general contractor to price, and uses to decide on a site and raise capital.
The final set is built on it. Harford County, Maryland writes the hand-off into its procedure: the developer submits a concept plan or preliminary site plan, the department circulates it to county and state agencies and schedules a public Development Advisory Committee meeting, a preliminary plan approval letter of agreement sets the conditions, and only after that letter is executed may final construction drawings and plats go to Public Works and Planning and Zoning [27]. From there the engineer of record adds the grading, drainage, stormwater, utility and structural design, the land surveyor adds the boundary and topographic survey and any plat, and the architect of record adds the sealed building set; in New Jersey each professional seals the sheets within that profession's scope [2]. Innowave plans are preliminary by design, and engineering is done by the client's engineer of record, who builds the sealed set on the approved layout.
Clocks and expiry
A preliminary approval does not last forever, and its life matters for land contracts, loan timing and phasing.
| Jurisdiction | Preliminary or concept stage | Final stage |
|---|---|---|
| New Jersey | Board acts within 45 or 95 days; approval confers rights for three years (N.J.S.A. 40:55D-49) [1] | Board acts within 45 days; two years of zoning protection (N.J.S.A. 40:55D-52) [1] |
| Harford County, MD | Concept plan valid 5 years; preliminary plan valid 2 years, with one 2-year extension [28] | Not stated |
| Carroll County, MD | Concept site plan void 12 months after Commission review [13] | Not stated |
| Puyallup, WA | Preliminary site plan "null and void if not exercised within two years" [29] | Not stated |
When a concept approval runs out, the work goes back to the start: Harford County requires a new concept plan once the concept validity period ends [28]. Building the schedule backward from these dates keeps a layout from expiring while the engineering is still being drawn.
Where to go next
For the plan itself, the preliminary site plan service is the starting point: the layout, yield and site data table a concept or preliminary submittal needs, drawn for the engineer and architect of record to build on. Site plan services covers the wider set of deliverables. For who seals what, state by state, read who prepares a site plan and do I need an architect for a site plan; for the basics, see what is a site plan. The jurisdictions that take a preliminary plan without a seal are collected in where unsealed site plans are accepted, and a homeowner's permit drawing is covered in site plan for a permit and permit site plans.
Stage rules also differ by asset class. The hubs for RV park site plans and single-family and townhome site plans set out the standards and approval paths for those programs, and the model project in Polk County, Florida lays out a Florida RV park approval path in order. The state pages for Delaware and Iowa cover each state's approval layers and leading jurisdictions, and Maryland is the state behind most of the county sequences above. For how review time adds up, see your permit clock starts later than you think. To scope a preliminary plan for a specific parcel, start a project.
Frequently asked questions
What is the difference between a preliminary and a final site plan?
The preliminary plan fixes the use, layout, access and yield for review; the final plan adds the engineering, survey and building detail that permits and recording rest on, sealed by the professionals of record. New Jersey runs them as two approvals: a board acts on a preliminary site plan within 45 or 95 days and on a final site plan within 45 days, or the plan is approved by default [1].
Does a preliminary site plan need a seal?
Often not. Maine's engineering rule exempts documents clearly marked PRELIMINARY or PROGRESS [4], and Vermont's planning statute does not require a purely local site plan to be sealed [21]. Some places want a seal at the first filing: Sussex County, Delaware requires the seal of a Delaware land surveyor or professional engineer on site plans, and Cedar Rapids, Iowa requires a registered civil engineer's certification on its site development plans [16, 18].
Who prepares the final site plan?
The professionals of record. In New Jersey a professional engineer seals the grading, drainage, utilities, paving and stormwater, a land surveyor seals the boundary and topographic survey, and an architect seals the building sheets [2].
How long does a preliminary approval last?
It depends on the code. New Jersey's preliminary approval confers rights for three years and final approval two years of zoning protection [1]; Harford County, Maryland holds a preliminary plan for 2 years and a concept plan for 5 years [28]; Puyallup, Washington makes a preliminary site plan "null and void if not exercised within two years" [29].
Is a concept plan the same as a preliminary plan?
Sources
- 1)Municipal Land Use Law, N.J.S.A. 40:55D-1 et seq. (sections 40:55D-46, 40:55D-49, 40:55D-50 and 40:55D-52), State of New Jersey.
- 2)N.J.A.C. 13:40-7, 13:40-8 and 13:27-7, division of responsibility in submission of site plans and major subdivision plats, and sealing, New Jersey State Board of Professional Engineers and Land Surveyors; New Jersey State Board of Architects.
- 3)Alaska Statutes AS 08.48.221, seals, State of Alaska (Board of Registration for Architects, Engineers, and Land Surveyors). Accessed 2026-09-01.
- 4)Board Rule 02-322 CMR Chapter 2, section 11, Maine Board of Licensure for Professional Engineers. Accessed 2026-08-31.
- 5)WAC 196-23-020, seal and stamp usage, Washington State Legislature. Accessed 2026-08-02.
- 6)430-RICR-00-00-1.7, application of the seal, Rhode Island State Board of Registration for Professional Engineers (via Cornell LII). Accessed 2026-08-31.
- 7)Iowa Admin. Code r. 193C-6.1(4), State of Iowa. Accessed 2026-08-30.
- 8)Iowa Building Code Official's Handbook (September 2019 edition), Iowa design licensing boards and Building Code Bureau (hosted by DIAL). Accessed 2026-08-30.
- 9)NCEES Model Rules (2024), Rule 240.20A, NCEES (ncees.org). Accessed 2026-07-30.
- 10)Residential subdivision process, Baltimore County, Maryland. Accessed 2026-08-31.
- 11)Montgomery County Planning Board Regulation, administrative procedures, Montgomery County, Maryland. Accessed 2026-08-31.
- 12)Application Process for Development, Anne Arundel County, Maryland. Accessed 2026-08-31.
- 13)Carroll County Code section 155.052, Carroll County, Maryland (codelibrary.amlegal.com). Accessed 2026-08-31.
- 14)Site Development Plan Process (2025), Howard County, Maryland. Accessed 2026-08-31.
- 15)Unified Development Code, Chapter 40, sections 40.31.112 to 40.31.114 (newcastlede.gov), New Castle County, Delaware. Accessed 2026-08-31.
- 16)Sussex County Code, site plan submission requirements (ecode360.com/8885359), Sussex County, Delaware. Accessed 2026-08-31.
- 17)Major Land Development Project checklist, City of Providence, Rhode Island. Accessed 2026-08-31.
- 18)Site Development Plans, City of Cedar Rapids, Iowa. Accessed 2026-08-30.
- 19)Appendix 7, Recreational Vehicle Park Development Regulations (2023), Jefferson County, Texas. Accessed 2026-10-09.
- 20)Fla. Admin. Code Chapter 64E-15 (2018 version), including R. 64E-15.010, Florida Department of Health. Accessed 2026-10-09.
- 21)24 V.S.A. Chapter 117, Vermont Legislature. Accessed 2026-08-31.
- 22)Site Plan Review Application and Checklist, City of Hattiesburg, Mississippi. Accessed 2026-08-31.
- 23)Planning and Zoning, City of Williston, North Dakota. Accessed 2026-09-01.
- 24)Building permit applications, City of Williston, North Dakota. Accessed 2026-09-01.
- 25)eTools: Sketch Plans, Chester County, Pennsylvania (chescoplanning.org). Accessed 2026-10-07.
- 26)Section 157.051, Types of site plans; when required, O'Fallon, Illinois (codelibrary.amlegal.com). Accessed 2026-10-07.
- 27)Subdivision Review and Approval Process, Harford County, Maryland. Accessed 2026-08-31.
- 28)Harford County Subdivision Regulations (January 22, 2010 update), Harford County, Maryland. Accessed 2026-08-31.
- 29)Chapter 20.89, Preliminary Site Plan, City of Puyallup, Washington (codepublishing.com). Accessed 2026-10-07.
How these sources were chosen and when the page is reviewed: how we research.