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What can I build on my lot?

What you can build is set in four layers: the zoning district, the district’s dimensional rules (setbacks, height, lot coverage, floor area), rules that depend on the lot itself (a corner, a flood zone, an easement), and the building code with its permits. Find the district first: every number follows from it.

Updated . General information, not legal advice: the city’s code and its planning staff decide for your lot.

Find the zoning district

Zoned cities and many counties divide land into districts, each with a code name such as R-7.5(A), SF-3 or RS-1. The district is on the city’s zoning map, usually an online map on the planning department’s site that you can search by address. The county appraisal record sometimes lists a zoning code too, but cities rezone, and the map is the authority.

Some places have no zoning at all. Houston is the best-known example: it has no use districts, but its development code still sets lot sizes and building lines, and many neighborhoods are bound by deed restrictions that the city helps enforce. Land outside city limits falls under the county, which in many states zones little or nothing.

Read the district’s dimensional rules

The district’s section of the zoning code, often a table, gives the numbers that shape a building:

  • Setbacks: how far a building must stay from the front, side and rear property lines. See What are setbacks?
  • Height: a maximum in feet, sometimes also in stories, measured the way the code defines it (to the ridge, or to the midpoint of a pitched roof, from the average grade).
  • Lot coverage: the share of the lot that buildings may cover.
  • Floor-area ratio (FAR): the total floor area as a multiple of the lot area, where the district sets one. See Lot coverage and floor-area ratio.
  • Minimum lot size and width, the number of homes per lot, and parking.

Read the code itself rather than a summary. Summary sheets simplify and fall behind: in September 2026, Dallas’s own summary of its residential districts listed R-13(A) at 40% lot coverage while the code said 45%.

Work out the envelope and the largest building

Take the setbacks off the lot and what remains is the zoning envelope: the area a building may stand on. Coverage, floor area and height then decide how much of it you can use.

Example

A 50 × 150 ft lot (7,500 sq ft) with a 25 ft front, 5 ft side and 10 ft rear setback, 40% lot coverage, a 35 ft height limit and no floor-area ratio:

Envelope width50 − 5 − 5 = 40 ft
Envelope depth150 − 25 − 10 = 115 ft
Zoning envelope40 × 115 = 4,600 sq ft
Coverage cap40% × 7,500 = 3,000 sq ft
Largest footprint3,000 sq ft
The envelope is the outer limit, not what you may build: here the coverage cap, not the setbacks, sets the footprint. On two stories under the height limit that is up to 6,000 sq ft of floor area, unless a floor-area ratio caps it lower.

Check the rules that depend on the lot

  • Corner and through lots: a second street side usually gets a larger setback than an interior side. See Corner lot setbacks.
  • Flood zones: in a FEMA Special Flood Hazard Area the lowest floor must sit above the base flood elevation, and some cities add rules of their own.
  • Easements and building lines: a utility easement or a building line drawn on the subdivision plat can keep a structure off land the zoning allows.
  • Overlay districts: historic, conservation and neighborhood overlays add rules on top of the base district.
  • Deed restrictions and HOA rules: private covenants can be stricter than zoning, and the city does not check them for you.

Confirm with the city before you commit

A zoning answer is a first picture. Before you buy, pay for a design or apply for a permit, ask the city’s planning or zoning desk to confirm the district and the numbers for your parcel. Many cities answer by email, and many issue a written zoning verification letter for a fee. The building permit then checks the building code: fire separation, exits, energy and structure.

How the Lot Report does this

The Lot Report runs these steps for one US address. It finds the parcel and its zoning district, takes each rule from the city’s own code with the section and a quote checked on the page (or from the zoning data we license, where it carries a value), and marks every number it could not confirm as an estimate. It then draws the zoning envelope and the largest building the limits allow as a site plan and a 3D model, and writes up what fits. See a sample report (opens in a new tab) made for an invented lot.

Questions

How do I find out what my lot is zoned?

Search the address on your city’s zoning map, usually an online map on the planning department’s site. Outside city limits, check the county. The county appraisal record sometimes shows a zoning code, but the city’s map is the authority.

Is the zoning envelope the size of the house I can build?

No. The envelope is what remains after the setbacks. Lot coverage, a floor-area ratio and the height limit usually allow less than the whole envelope, and the largest building is the smallest of what those limits leave.

Can I build anything I like if my city has no zoning?

No. Development rules such as building lines and minimum lot sizes, deed restrictions, flood rules and the building code still apply. Houston, the largest US city without use zoning, regulates all of these.

Do I need a permit to build an addition?

In almost every US city, yes: a building permit, for which the city checks zoning and the building code. Small sheds below a size the city sets are often exempt from the permit, but they usually still have to meet the setbacks.

Look up your own address

Enter an address: the Lot Report gathers the county record, the house’s condition, home values, schools, walkability, flood risk and the zoning rules, and draws the largest building they allow.

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