When you need one
Fairfax County regulates any project that disturbs 2,500 square feet of land or more, because the county falls under Virginia’s Chesapeake Bay Preservation Act. The county says an infill lot grading plan is required for single-family construction that will disturb more than 2,500 square feet and includes stormwater management improvements (Fairfax County Land Development Services).
That threshold comes up fast. Disturbed land includes the house footprint, the driveway, the trench for utilities, the area where the excavator works and where materials are stored. Almost every new house and knockdown rebuild crosses it.
For smaller projects there are lighter options. A conservation plan can be used for residential additions and structures that disturb between 2,500 and 5,000 square feet when no stormwater improvements are needed, and work under 2,500 square feet usually just needs a house location plat (Fairfax County site related plans guide).
What goes on the plan
- Existing and new buildings, driveways and walks
- Existing and new contours (the topography)
- Erosion and sediment controls during construction: silt fence, a construction entrance, inlet protection
- How stormwater leaves the lot today and after the new house, and the stormwater measures that handle the difference (dry wells, infiltration trenches, planters)
- Trees to keep, trees to remove and tree protection
- Utility connections, and the septic field if there is one
The plan must be certified by a licensed engineer, land surveyor, landscape architect or architect, and it has to be approved before the building permit is issued.
Why it matters for your schedule and budget
- It comes first. The county reviews the grading plan before it issues the building permit, so start it as soon as you have a house footprint. Many builders run it in parallel with the house design.
- Stormwater is a real cost. Bigger new houses add roof and driveway area, and the plan has to show how that extra runoff is handled. Ask for the stormwater design early so it is in your budget.
- Neighbors notice drainage. Problems that cross a lot line are among the most common complaints after a rebuild. A good plan protects you as much as the neighbors.
- Other approvals can stack on top. Lots in a Resource Protection Area near a stream, in a floodplain, or with steep slopes get extra review.
Inside the Town of Vienna
The Town of Vienna handles its own zoning and has its own large-scale residential infill lot checklist for projects over 2,500 square feet of land disturbance, while Fairfax County still issues the building permit. Check both.
Questions to ask your builder
- Who draws the grading plan, and is it in your price?
- How much land will we disturb, and what stormwater measures do you expect?
- Which trees can we save, and how will you protect their roots?
- How long has county review taken on your last few projects?
Start with the lot checker to see your zoning and sewer status, then read the knockdown rebuild guide.
