What Changed and Why It Matters
In 2024, Loudoun County adopted amendments to its Zoning Ordinance that introduced new restrictions on development in the county's rural districts. The changes were driven by two policy objectives: protecting prime farmland soils from non-agricultural development and aligning the ordinance with the county's 2019 General Plan guidance on rural land use.
For most landowners with rural parcels in Loudoun County, the 2024 amendments have limited practical effect. For owners of the approximately 685 parcels containing 70% or more prime farmland soils, the amendments created new building envelope constraints that directly affect where structures can be placed.
Understanding whether your parcel is affected -- and how -- requires specific investigation. This article provides the framework for that investigation.
The Prime Farmland Soil Designation
Prime farmland soils are soils that have the physical and chemical characteristics best suited to producing food, feed, fiber, forage, and oilseed crops. The USDA Natural Resources Conservation Service (NRCS) classifies soils as prime farmland based on organic matter content, permeability, drainage, texture, and other factors.
In Loudoun County, prime farmland soils are heavily concentrated in the county's central and eastern agricultural belt -- the land east of the Blue Ridge foothills and west of the suburban development corridor. The Piedmont soils of this region, particularly those derived from limestone parent material in the Leesburg area and the Virginia limestone belt, are among the highest-rated agricultural soils in the Mid-Atlantic region.
The 2024 amendment applies to parcels where 70% or more of the soil area is classified as prime farmland. The threshold is based on the NRCS soil survey data for Loudoun County.
What the Amendment Restricts
For the approximately 685 affected parcels, the 2024 amendment creates additional limitations on where structures can be placed:
Building envelope constraints: Structures must be sited on non-prime farmland soils where possible. Where a parcel has areas of non-prime soils, the building envelope must be located on those areas rather than on prime farmland soils. This requirement can significantly constrain building site location on parcels where prime farmland soils cover most of the parcel area.
Impervious surface limits within prime farmland areas: New impervious surfaces (buildings, driveways, parking) within areas designated as prime farmland may be subject to additional review.
Documentation requirements: Applications for building permits on affected parcels may require documentation demonstrating that the building envelope has been sited to minimize impacts on prime farmland soils, including a soils map prepared by a licensed soil scientist or from NRCS soil survey data.
What the Amendment Does Not Change
The 2024 amendment does not change:
- The by-right permitted uses in AR-1 and AR-2 districts (primary residences, accessory dwellings, agricultural structures, farm wineries, farm breweries)
- The minimum lot size requirements for the relevant zoning districts
- The setback requirements (from road rights-of-way, property lines, streams)
- The accessory dwelling provisions
- The conservation easement framework
If your parcel does not contain 70% or more prime farmland soils, the 2024 amendment does not affect your permitted uses or building envelope constraints.
How to Determine If Your Parcel Is Affected
Step 1: Pull the NRCS Web Soil Survey for your parcel. The NRCS maintains a free online soil survey at websoilsurvey.sc.egov.usda.gov. Enter your parcel's address or navigate to it on the map, then generate a Soil Map for your area of interest. The map legend identifies prime farmland-rated soils.
Step 2: Calculate the percentage of prime farmland soils on your parcel. The Web Soil Survey's Area of Interest calculations can compute the acreage of each soil type within your parcel boundary. If 70% or more of your parcel area is prime farmland soil, you are likely in the affected category.
Step 3: Request a zoning confirmation letter from Loudoun County Planning. The letter should specifically address whether the 2024 amendment applies to your parcel and what it requires.
Step 4: Consult a land use attorney. If the amendment applies to your parcel, a land use attorney can help you understand how the building envelope constraints interact with your intended program and what documentation will be required for the building permit application.
The Practical Effect on Estate Construction
For most rural landowners planning custom estate construction, the 2024 amendment has one of two effects:
No effect: Your parcel does not meet the 70% prime farmland threshold, or your intended building sites are already on non-prime farmland soils (wooded hillsides, areas with drainage limitations, rocky outcrops). Most estate properties in western Loudoun -- particularly those in the Blue Ridge foothills with varied topography -- fall into this category.
Building site relocation: Your parcel meets the threshold and the preferred building site is on prime farmland soils. The amendment requires the building envelope to be relocated to non-prime soil areas. Depending on the parcel, this may mean a modest adjustment to the building site location or a more significant redesign.
The key is to determine which category applies to your parcel before any design dollars are committed. A soil mapping exercise conducted before design begins costs $2,000-$5,000. A design revision required mid-schematic design because the preferred building site is non-compliant with the 2024 amendment costs significantly more.
The Broader Zoning Context
The 2024 amendment is part of a longer-term trajectory in Loudoun County's approach to rural land development. The county's General Plan has consistently expressed a policy preference for concentrating rural development on non-prime agricultural soils and preserving the county's agricultural land base.
For landowners who purchased rural land in western Loudoun before 2024, the amendment may affect previously assumed development rights. The appropriate response is not alarm but investigation: determine whether the amendment applies to your specific parcel and what, if any, adjustment to your intended program is required.
For landowners currently searching for rural land in Loudoun County, the 2024 amendment adds one more item to the pre-purchase due diligence list: confirm whether the parcel is in the affected category and whether the most attractive building sites on the parcel are on prime farmland soils.
FAQ
Q: How do I know if my specific parcel is among the 685 affected by the 2024 amendment? Request a zoning confirmation letter from Loudoun County Department of Planning and Zoning. Include your parcel's PIN and ask specifically whether the parcel is subject to the 2024 prime farmland building envelope constraints. Alternatively, use the NRCS Web Soil Survey to calculate the percentage of prime farmland soils on your parcel -- if it is below 70%, the amendment likely does not apply.
Q: Does the 2024 amendment affect my right to build a primary residence on my AR-1 parcel? The amendment does not affect the right to build -- primary residences remain by-right in AR-1. It affects where on the parcel the residence can be sited. If your parcel is affected, the residence must be located on non-prime farmland soils where feasible. This is a siting constraint, not a prohibition.
Q: If my preferred building site is on prime farmland soils, are there any exceptions? Where a parcel's entire area consists of prime farmland soils, or where no practical alternative building site exists on non-prime soils, Loudoun County Planning may work with the owner on a site that minimizes prime farmland impacts. This situation should be evaluated with a land use attorney and documented carefully in the permit application. Pre-application meetings with Loudoun County Planning are available and recommended in this circumstance.
Planning construction on rural land in Loudoun County? Understanding how the 2024 amendments affect your specific parcel is a critical first step. hearthstonedesignbuild.com/contact | (571) 556-1900