2026 SESSION

INTRODUCED

26105107D

HOUSE BILL NO. 1356

Offered January 19, 2026

A BILL to amend the Code of Virginia by adding in Article 4 of Chapter 2 of Title 33.2 a section numbered 33.2-280.3 and by adding in Article 2.6 of Chapter 3.1 of Title 62.1 a section numbered 62.1-44.15:85, relating to precipitation design standards; non-stationary precipitation; climate-adjusted rainfall.

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Patron—Convirs-Fowler

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Referred to Committee on Agriculture, Chesapeake and Natural Resources

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Be it enacted by the General Assembly of Virginia:

1. That the Code of Virginia is amended by adding in Article 4 of Chapter 2 of Title 33.2 a section numbered 33.2-280.3 and by adding in Article 2.6 of Chapter 3.1 of Title 62.1 a section numbered 62.1-44.15:85 as follows:

§ 33.2-280.3. Precipitation design standards for state transportation projects.

A. The Department shall incorporate climate-adjusted precipitation values into the design and construction of all stormwater management facilities, culverts, bridges, and other transportation infrastructure, consistent with the precipitation design standards established by the State Water Control Board pursuant to § 62.1-44.15:85.

B. The Commissioner shall ensure all relevant design manuals and specifications issued by the Department, including the VDOT Drainage Manual and Structure and Bridge Manual, are updated in accordance with this section.

C. The Department shall coordinate with the Department of Environmental Quality and other state agencies to maintain consistency among precipitation design standards affecting transportation and flood-resilience infrastructure.

D. The Department shall identify and pursue all funding sources that can be used to implement this section, including programs related to transportation resilience, flood mitigation, and climate adaption.

E. Nothing in this section shall prohibit a locality or a regional transportation authority from adopting more stringent precipitation design standards to address local or regional flood-risk conditions.

§ 62.1-44.15:85. Precipitation design standards; non-stationary precipitation; climate-adjusted rainfall.

A. As used in this section:

"Board" means the State Water Control Board.

"NOAA" means the National Oceanic and Atmospheric Administration.

B. Notwithstanding any other provision of law, all state agencies and political subdivisions of the Commonwealth, including the Department of Transportation and other entities responsible for public infrastructure, shall incorporate climate-adjusted precipitation values when establishing design standards for stormwater management facilities, floodplain management, culverts, bridges, and other public infrastructure systems and structures, including for projects developed through a public-private partnership.

C. The Board shall serve as the lead agency responsible for establishing and maintaining precipitation design standards. Such precipitation design standards shall include the most recent precipitation frequency estimates published in NOAA's national precipitation frequency atlas to account for observed and projected increases in precipitation intensity, frequency, and duration. The Board shall determine the appropriate projection time to reflect changing climate conditions.

D. The Board shall review at least annually the requirements and related technical criteria provided in the Virginia Erosion and Stormwater Management Regulation (9VAC25-875) to determine whether the most recent NOAA atlas precipitation frequency estimates remain reflective of current conditions and sufficient to protect public safety, property, and infrastructure investments. The Board may adopt standards or issue guidance through regulation consistent with subdivision A4 of § 2.2-4006 as necessary to expedite implementation of this section.

E. A locality and all political subdivisions of such locality shall ensure that stormwater management design manuals and standards are adopted in accordance with this section.

F. The Board shall identify all funding sources, including federal resilience or infrastructure programs, that can be used for costs associated with establishing and maintaining precipitation design standards pursuant to this section. The Board may enter into all contracts and agreements necessary to receive such funding.

G. Nothing in this section shall prohibit a locality from adopting more stringent precipitation design standards to address local or regional flood risks.

2. That the Department of Environmental Quality, Department of Transportation, and any other state agency shall update any relevant manuals and design standards consistent with the provisions of this act by July 1, 2027.

3. That the State Water Control Board and the Department of Transportation may use an abbreviated rulemaking process under subdivision A 4 of § 2.2-4006 of the Code of Virginia to adopt interim guidance or regulations implementing this act, ensuring that updated precipitation design standards take effect no later than July 1, 2027.

4. That until NOAA Atlas 15 precipitation frequency estimates are published and adopted by the Commonwealth, the State Water Control Board shall, in consultation with the Department of Transportation, issue guidance setting out a requirement that precipitation values derived from NOAA Atlas 14 be increased by at least 20 percent when used for design purposes.