Please accept the following comments on the proposed changes to 9VAC25-875-580 and 590.

The proposed change in 9VAC25-875-580.A.1, to the total phosphorous load for plans submitted on or after July 1, 2025, does not provide any standards for plans that were submitted before July 1, 2025, but have yet been approved, nor plans that have been approved and are still under construction after July 1, 2025, that may need to submit revisions to the plan due to circumstances that arise. The lack of regulatory basis for design and review for approved and pending plans, or revisions to approved plans will create confusion and hardship for ongoing developments, and uncertainty for localities that are the VESMP Authority. Please retain in the regulations a reference to the prior standards and requirements as a basis for the approval of pending plans and revisions to approved plans.

The proposed change in 9VAC25-875-590.B remove the citation of the specific version and date of the Standards and Specifications for nonpropriety BMPs, and instead reference the Virginia Stormwater Management Handbook. My recollection is the specific date and version were included in the Regulations to provide certainty and continuity for design professionals, as well as the locality as the approval authority, during the design, review, approval, construction and inspection, and/or long-term maintenance of the stormwater facilities. I understand the goal of the Handbook is to update the standards and Specifications more frequently, however, the unintended consequence is that this state of perpetual flux will create confusion, uncertainty and ambiguity for the life of the BMP, and no permanent, archived documentation of the prior standards. Please consider implementing a defined, predictable schedule of code changes and effective dates for changes, such as the way updates to the Virginia Uniform Statewide Building Code are accomplished. The USBC is updated on a defined schedule, allows for design plans to refence a specific code cycle, and a 1-year transition (grace) period during which designers can choose to seek approval under the "old" code, or redesign to the "new" code, based on the circumstances of the given project. During the transition period, the project must select and use the one set of code standards throughout the design (no mix-and-match between standards).  Please also consider including an option that applicants may, during the transition period, choose to design to either the "old" or the "new" requirements and corresponding specifications, e.g., use the VRRM 3.0 in conjunction with the 1999 SWM Handbook specifications, or use the VRRM 4.1 but with the new Handbook. 

With respect to the timing, the proposed effective date of July 1, 2025, creates a virtually impossible mandate for localities that operate as the VESMP Authority. Once the Regulations are adopted, the locality must then navigate through the local legislative process to amend the local Ordinances and have the new requirements adopted and effective. Please consider a delayed effective date to provide a reasonable time for localities to comply.

Thank you for the opportunity to comment.

Please note that these are staff comments and do not represent an adopted position of the Fairfax County Board of Supervisors.