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Steep slopes and problem soils in Arlington County, VA

Steep slopes of 25% or more next to stream buffers are part of the RPA, so work there needs county review. Disturbing 2,500 sq ft or more anywhere needs a Land Disturbing Activity permit.

A person last checked these rules on October 20, 2026. This is guidance only, so confirm with Arlington County before you build.

The details

  • The RPA includes adjoining steep slopes of 25% or more.High confidence
  • The building official can ask for a soils report where marine clay or fill is suspected. Ask before designing a foundation or wall.Medium confidence

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Common questions

Do steep slopes or soils like marine clay change what I can build in Arlington County?
Steep slopes of 25% or more next to stream buffers are part of the RPA, so work there needs county review. Disturbing 2,500 sq ft or more anywhere needs a Land Disturbing Activity permit.

Sources

  1. Arlington County, Resource Protection Area (RPA) and the Chesapeake Bay Preservation Ordinance. Checked 2026-10-21
    [RPA review is required for] new or replaced fences and retaining walls; new paved surfaces, including gravel; decks, sheds, and pergolas; removing trees 3 inches or more in diameter... [A CBORC exception is required for] increasing impervious cover in the …
  2. Virginia USBC, 13VAC5-63-80 Section 108.2 (pools, mechanical, electrical and flood-area items). Checked 2026-10-21
    8. Swimming pools that have a surface area not greater than 150 square feet and are less than 24 inches deep... 14.4 Replacement of mechanical appliances provided the equipment is not fueled by gas or oil in Group R-2 where serving a single-family dwelling …

Disclaimer: This is general information, not legal or professional advice for any one property. Codes change. SetbackIQ is not a zoning determination, a permit, or a survey, and it does not replace an architect, engineer, or lawyer. Confirm with your building and zoning offices before you build, buy, or sign a contract.