How to draw a site plan for a building permit

Everything on a site plan hangs off the property lines, so start by finding accurate ones. In order of reliability:

• A boundary survey. The best source. It shows the lines, their lengths and bearings, corner markers, and often existing buildings and easements. Check your closing documents; you may already have one.
• The recorded plat. If your lot is in a subdivision, the plat on file with the county recorder shows the lot dimensions and platted easements.
• County assessor and GIS records. Most counties have an online parcel viewer with lot lines, the parcel number and the acreage. It’s handy, but the lines are approximate, not survey-grade.
• Your deed. The legal description describes the boundary in words, and title documents list recorded easements.

Also look up your zoning district and its setback, height and lot coverage rules. The county or city planning department has them, often online.

Draw each property line with its length and, if your survey has them, its bearing, such as N 89°12’30” E 150.00’. Work around the lot until the lines close back at the starting corner. If they don’t close, recheck your numbers before you go further.

Label the street and show the edge of the road or right-of-way. Many departments also want the parcel number and the lot’s total area on the sheet.

Every site plan needs a north arrow and a stated scale. Choose a scale that fits the whole lot on your sheet with room for notes. For a typical residential lot, that’s often 1 inch to 20 feet or 1 inch to 30 feet. Large rural parcels may need a smaller scale, plus an enlarged view of the building area.

Add a title block with the project address, parcel number, owner’s name, sheet title, date and your contact information.

Draw the footprint of every building on the lot, existing and proposed, with its outside dimensions. Label each one (“existing house,” “proposed 12 by 16 shed”) so there’s no confusion. Include decks, porches, carports, pools, and other accessory structures, because many zoning codes count them.

Show roof overhangs if your jurisdiction measures setbacks to the eaves instead of the wall. Use a different line type or hatching for proposed work so it stands out.

This is the part reviewers check first. For each building, dimension the shortest distance to each nearby property line, and the distance between buildings. Measure square to the property line from the closest point of the structure.

It helps to show the required setback lines as dashed lines, so the reviewer can see at a glance that the building sits inside them. If you’re close to a line, consider having the corners staked by a surveyor. A few inches can matter.

Show every easement with its width and purpose: utility, drainage, access, or conservation. Buildings generally can’t go in an easement, and some easements restrict fences and driveways too. Your survey, plat and title documents are where easements are recorded.

• Driveway. Its location, width and surface, and where it meets the road.
• Utilities. Overhead or underground power, water, gas, sewer and communications lines, plus meter locations and new service runs.
• Septic. The tank, drain field and reserve area, with distances to buildings, wells and property lines. Your health department sets these distances.
• Well. The well location and its distances to the septic system, buildings and property lines.

In the United States, call 811 before any digging so buried utilities get marked.

Use arrows to show which way water flows across the lot, and show where roof downspouts discharge. Water should drain away from buildings and shouldn’t be pushed onto a neighbor’s property. Some jurisdictions also want spot elevations or contour lines, especially on sloped lots or when you’re adding a lot of hard surface.

If your zoning code limits lot coverage, add up the footprint of every building and divide by the lot area. Some codes also limit impervious surface, which counts driveways, patios and walks too. Show the math on the sheet:

Example numbers only. Use your own lot and your code’s definition of coverage.

• Property lines close, with lengths and bearings labeled
• North arrow, scale and title block are on the sheet
• Every building is labeled existing or proposed and dimensioned
• Setbacks are dimensioned to every nearby property line
• Easements, driveway, utilities, septic and well are shown
• Drainage and lot coverage are shown if required
• Everything is readable at the paper size you’ll submit

Then compare it against your building department’s checklist one last time. Requirements vary, and they have the final say.

AI CAD PRO is free site plan and plot plan software for Windows. Attach your survey or plat as a PDF, describe what you’re building and where, and the AI assistant draws the property lines, buildings, dimensions and notes as editable CAD objects. Check every line against your source document; you know your lot best.

The Resolution center lists missing information with a recommendation and where to find it, and drafting checks catch overlapping annotations and overflowing notes. Draw the lot once, and you can reuse the plot plan in your next project. Print preview matches the PDF you export.