Two approvals, one subdivision
Larger subdivisions split the platting process into two distinct approvals. The split exists because subdivision design and subdivision law have different precision requirements: a city can evaluate street layout and drainage from a good design drawing, but recording lot lines that govern property rights forever demands a sealed, monumented, closure-checked survey. The preliminary plat handles the first job; the final plat handles the second.
Side by side
| Field | Preliminary plat | Final plat |
|---|---|---|
| Purpose | Lock the subdivision design — layout, streets, easements, drainage | Create the lots as a matter of legal record |
| Precision | Design-grade drawing; dimensions can still shift | Survey-grade instrument; bearings, distances, and monuments are final |
| Recorded? | No — it is an approval, not a record document | Yes — filed with the county clerk |
| What it authorizes | Engineering construction plans; often site infrastructure | Lot sales, lot financing, and building permits |
| Typical reviewers | Planning, engineering, utilities, fire — full design review | Conformance check against the approved preliminary + survey QC |
| Can it change? | Yes — revisions during engineering are routine | Only by replat or amending plat after recording |
| Lifespan | Expires (commonly 1–3 years) if no final plat follows | Permanent until superseded by a replat |
What happens between the two
The gap between preliminary and final plat — commonly 6 to 18 months — is not idle time. It is the subdivision's construction phase:
- 01Engineering plans
Civil engineers turn the approved preliminary layout into construction documents: street sections, storm sewer, water and sanitary design, grading and detention. The city reviews and approves these separately.
- 02Site infrastructure construction
Streets, drainage, water, sewer, and dry utilities get built. This is when excavation, paving, and utility contractors are hired and working — before a single building permit exists.
- 03Inspection and acceptance (or bonding)
The jurisdiction inspects the improvements. Most require completed-and-accepted infrastructure — or a financial guarantee covering it — before the final plat may proceed.
- 04Final plat approval and recording
The final survey is checked against the approved preliminary plat, signatures and tax certificates are collected, the authority certifies it, and the plat is recorded. Lots now legally exist, and vertical permits can issue.
When the two-step process doesn't apply
Not every plat runs the full sequence. Minor plats (small lot counts, no new streets), replats, and amending plats usually go straight to a recordable final document in a single review. Houston is a notable local variation: most plats there move through a single-track Planning Commission process on a biweekly cycle, with the preliminary/final distinction mattering mainly for large master-planned developments.
Common questions
For the document fundamentals, start with what is a plat. To read the recorded drawing itself, see how to read a plat map.