For ADU builders

The ADU on the Lot, With Every Number the Review Asks For.

An accessory dwelling unit review is a site plan review first: where the unit sits, how far it is from the side and rear lines and from the main house, how much of the lot is covered, where the parking and the path to the street are. PlotForge™ loads the recorded lot from the address, drops the existing house on it, and you place the ADU at its real size with the setbacks, the separation and the coverage written on the sheet.

What does an ADU site plan need to show?

An ADU site plan shows the property lines with dimensions, the existing main house and garage, the accessory dwelling unit drawn to scale at its real size, the distances from the unit to the side and rear property lines and to the main house, the lot coverage, the parking space if one is required, and the walkway from the street to the unit's door.

What the plan reviewer looks for on an ADU site plan

ADU ordinances are written as a list of numbers: maximum size, side and rear setbacks, separation from the main house, lot coverage, height and parking. The site plan is where the reviewer checks every number except height:

The lot, dimensioned — the recorded property lines with every side's length, loaded from the address

The main house and garage — placed from public footprint records in one click, so the separation distance reads from the real wall

The ADU at its size — detached, attached or a garage conversion: a rectangle at the exact width × depth, with its square footage

Setbacks and separation — the distances to the side and rear lines and to the main house label themselves and update as you move the unit

Lot coverage — structures and hardscape total on the sheet, the number behind the coverage limit

Parking, path and utilities — the parking space as hardscape, the walkway from the street to the door, and notes for the utility connections

How an ADU builder draws the site plan

Type the address

The recorded lot loads to scale on the aerial with the owner and parcel number filled in.

Add the existing buildings

One click places the main house, the garage and the shed. Line a corner up with the roof on the aerial if it sits off.

Place the unit

Drop the ADU at its size in the back yard, or convert the garage footprint. The side, rear and separation distances label themselves.

Add parking, path and export

Trace the parking pad and the walkway, read the coverage, and export the to-scale PDF with the cover sheet. Export the DXF for the designer.

The tools ADU builders use

Auto-add existing buildingsThe main house and garage from public records in one click, corners draggable onto the roofline.How it works → Structure builderThe unit at its exact size; a garage conversion reuses the existing footprint with a new label.How it works → Automatic setbacksSide, rear and house-separation distances label themselves; hide the front-yard distances that do not matter.How it works → Live quantity takeoffStructures in square feet, hardscape in square feet and the impervious coverage, printed on the sheet.How it works → Driveway & sidewalk ribbonsThe parking pad and the walkway to the unit's door drawn to width, fused into one hardscape outline.How it works → DXF for CADThe lot, setbacks, structures and dimensions on named layers for the designer who draws the unit itself.How it works →

Which plan fits an ADU builder

Several ADUs in the pipeline

Contractor, $199/mo

Twenty permit-ready plans a month, every drawing tool and the DXF, plans saved per project so the planning-department revision is a reopen. See Contractor.

Feasibility before the contract

Site Feasibility Report

Before you price the job, a one-click report screens the lot for flood zone, wetlands, soils, slope and road frontage, and where PlotForge carries the jurisdiction's rules it pre-fills the setbacks. One plan credit. See the report.

One unit, one permit

Starter Pack, 3 plans for $49

Three clean exports for the submittal and two revisions, no subscription. Draw it first on the free 30-day trial. Compare plans.

▶ Watch the lessonSite Plan for a Deck, Shed or Addition Permit ▶ Watch the lessonAdd Existing Buildings to a Site Plan in One Click ▶ Watch the lessonHow to Draw a Driveway on a Site Plan

ADU builders FAQ

Does an ADU need a site plan?

Yes. Every ADU permit application reviewed against an ADU ordinance needs a site plan, because the ordinance's size, setback, separation, coverage and parking rules are all checked on it. Many jurisdictions publish an ADU-specific site plan checklist; PlotForge covers the items those checklists share.

How far does an ADU have to be from the property line and the main house?

That is set by your jurisdiction's ADU ordinance; many use a few feet from the side and rear lines and a set separation from the main house, and some states set a floor that cities cannot exceed. PlotForge labels the distances from the unit to the lines and to the house so you can slide it until the numbers match.

Can I draw a garage conversion?

Yes. The existing garage footprint loads with the house; relabel it as the ADU, add the new entry walk and any addition to it, and the setbacks and coverage read from the real footprint.

Do I have to show parking for an ADU?

It depends on the ordinance. Some jurisdictions require one space per unit, some waive it near transit or for conversions. Where it is required, trace the parking pad as hardscape at the size the ordinance specifies and it prints with its dimensions.

Can I check whether the lot can take an ADU before I bid?

Run a Site Feasibility Report on the parcel. It screens flood zone, wetlands, soils, slope and road frontage from public data, sketches the buildable area from the setbacks you enter, and checks what you drew against it. Where PlotForge carries the jurisdiction's building rules, the setbacks pre-fill and link to their code sections.

Is a PlotForge™ site plan a survey?

No. The property lines are the recorded parcel lines from public records, drawn to scale over an aerial photo. That is what most building departments accept for a permit site plan, and it is not a boundary survey or an engineered drawing. If your office requires a sealed survey for this project, PlotForge can trace that recorded survey as the boundary and the sheet prints a notice saying so.

Does it work where I am?

PlotForge™ covers all 50 states and Washington, D.C.; the only exceptions in the country are named on the coverage page. It is also expanding into Canada, starting with select counties in Ontario and Alberta. The most reliable check is free: sign up, type the address, and watch the lot load.

Draw the ADU site plan in minutes

Load the lot, add the house, place the unit, read the setbacks, the separation and the coverage. Free for 30 days, no credit card required; a clean, permit-ready export is $29.

Start an ADU Site Plan Free → See Every Drawing Tool