The Chesapeake Bay Preservation Ordinance was adopted to protect our local streams and the Chesapeake Bay from pollution due to land use and development. All of Arlington County’s water drains into the Potomac River and ultimately the Chesapeake Bay. In an effort to protect and improve the quality of these waterways, sensitive areas along streams throughout Arlington have been designated as Resource Protection Areas.
What is an RPA?
The Resource Protection Area, or RPA, includes streams, rivers, and other water bodies and the environmentally sensitive lands within 100 feet of these water resources. These areas are known as stream or wetland buffers, and help protect water quality by:
- filtering out pollutants from stormwater runoff,
- reducing the volume of stormwater runoff,
- minimizing erosion, and
- providing wildlife habitat.
A fully vegetated stream buffer can help protect private property by preventing erosion along a water body. Steep slopes (25 percent or greater) that are adjacent to buffers are also part of the RPA because of the potential for erosion in these areas.
In RPAs, existing trees and other vegetation are protected and building projects are regulated to protect water quality. Living Near a Stream: Understanding Resource Protection Areas
How do I know if there is RPA on my property?
RPAs include any area within 100 feet of a stream. Check the RPA maps below to find out if there is RPA on your property.
- View the Interactive Resource Protection Map
- View the Streams, Watersheds and RPA Map (Effective January 1, 2018)
You can also call Arlington County Department of Environmental Services (703-228-4488).
What types of things can I do in the RPA?
As a homeowner living in or near an RPA, you can help protect local streams and the Chesapeake Bay by preserving this valuable stream buffer. Many homeowner activities are allowed in the RPA, such as:
Gardening – Typical gardening activities are allowed, unless you are digging and exposing the soil of an area great than 50 feet by 50 feet (2500 square feet) or removing mature trees with a diameter of 3 inches or greater.
Home repair and maintenance – Repairs and maintenance work are allowed within the RPA without County review and approval, unless the work includes:
- The creation of new paved surfaces or buildings within the RPA,
- The disturbance of more than 2,500 square feet of land, or
- The removal of mature trees with a diameter of 3 inches or greater.
Trimming Vegetation for Sight Lines
Minor trimming and clearing of vegetation for sight lines and vistas is allowed. However, if such activities involve removal of trees, first contact DES at 703-228-4488 to determine if the proposed tree removal is permitted.
What Activities Require Approval in the RPA?
Except for the minor activities described in the previous section, most activities in the RPA require some level of County review and approval. In general, development is allowed in an RPA as long as the overall developed area does not increase or extend further into the RPA.
Replacing a Structure
Activities such as replacing an existing deck in the RPA or installing a new fence in the RPA, although considered allowable, must be approved by the County.
Creating a new structure or paved area in the RPA, such as building a retaining wall, an addition to your home, or a new home, generally will require an exception request. In all cases, the County will review the proposed RPA activity to ensure that water quality is protected.
The removal of mature trees with a diameter of 3 inches or greater requires County review and approval.
Ordinance Guidance Manual
Permitting and Construction Resources
- Tree Protection and Planting Standards (revised 5/1/15)
- Water Quality Impact Assessment Data Sheet and Exception Request Form
- Water Quality Impact Assessment Plan and Narrative Checklist
- 20-Year Tree Canopy Coverage Worksheet (revised 4/2017)
- Landscape Plan Checklist (updated 6/26/2015)
- Tree Protection Plan Example (added 5/1/15)
- Tree Notification Letter Example
The Chesapeake Bay Preservation Area (CBPA) map is a component of the County’s Chesapeake Bay Preservation Ordinance (Chapter 61) and is required by the Virginia Chesapeake Bay Preservation Act (1988) and Chesapeake Bay Preservation Area Designation and Management Regulations. The purpose of both the regulations is to improve the health of local streams, the Potomac River, and the Chesapeake Bay.
The CBPA map shows all lands identified as RPAs by the County Board and is more often referred to as the RPA map. The map was last updated in 2017. RPAs are the most sensitive lands adjacent to streams where water quality is more likely to be negatively impacted during development. RPAs in Arlington also include “such other lands considered by the County Board…to be necessary to protect the quality of State waters.” Under the “other lands” provision, the ordinance designates as RPA all natural and man-made stream channels mapped in the County’s GIS system, whether perennial or intermittent, along with a 100 foot buffer along both sides of such channels and any adjacent 25 percent or greater slopes.