Johnston County holds public hearing on revised stormwater ordinance; adoption eyed for Sept. 2

Johnston County held a public hearing Aug. 4 on proposed revisions to the county’s stormwater ordinance and design manual, with staff recommending the board consider adoption at its Sept. 2 meeting and an implementation date of Nov. 1, 2025.

The draft ordinance updates county requirements to reflect state nutrient-management rules (the Neuse rule) and a revised agreement with U.S. Fish and Wildlife, county utilities director Chandra Farmer and consultant Beth Umstead told the board. The package sets a minimum built-upon area (BUA) for new single-family lots served by septic systems, changes attenuation and water-quality requirements, removes the county’s land-dedication option and adds annual inspection and enforcement tools.

Why it matters: the changes affect how new subdivisions and other developments must manage stormwater quantity and quality, who must build and maintain detention features, and when developers may be exempted from on-site attenuation — decisions that affect development costs, long-term maintenance obligations and neighborhood drainage.

Key proposals and clarifications - Implementation and schedule: Staff said they would return Sept. 2 seeking adoption and recommend an effective date of Nov. 1, 2025. Designers may choose to proceed under existing rules if their projects are already in process; otherwise the new rules will apply to future permits. - Minimum BUA for septic lots: The draft design manual would require new residential subdivisions not served by public sewer to be designed to allow a minimum built-upon area of 6,000 square feet per lot (a design minimum, not a mandate that lots be built to that exact coverage). Staff said the 6,000-square-foot design target aims to allow typical homes, driveways and modest additions without triggering later redesigns. - Attenuation and design storms: For environmentally sensitive areas and the Middle Creek watershed, the county would require attenuation from the 1-year through the 100-year storm; elsewhere the draft requires attenuation from the 1-year through the 25-year storm. Engineers explained that multistage outlet controls are commonly used so a single constructed feature can provide the required performance for multiple storm events. - Small-subdivision exemption from attenuation: Single-family residential subdivisions of 19 lots or fewer that increase post-development runoff by 8% or less would be exempt from on-site attenuation (they would still be subject to water-quality requirements imposed by the Neuse rule). Nonresidential projects under certain thresholds (for example, less than 10,000 square feet of BUA) would also be exempt from attenuation. - Removal of land dedication: Staff proposed removing the county’s land-dedication buy-in option and instead requiring on-site treatment/attenuation. The change eliminates a prior program that allowed developers to buy into a fund to offset impervious surface; staff said the fund had been little used and that treating on-site offers more direct quality and quantity benefits. - Built-upon-area caps and offsets: The draft increases allowable BUA limits compared with the older program: proposed residential maximums in certain categories were described in range terms; nonresidential BUA could go higher (staff cited values up to 80% for nonresidential full built-out scenarios) while meeting nutrient-offset and design requirements under the Neuse rule. - As-built certification, bonding and annual inspections: The ordinance would require as-built certification from engineers, performance bonds or guarantees where appropriate, and an annual inspection report for stormwater control measures (SCMs). Inspections must be performed by a qualified registered engineer, landscape architect, or an individual who completed the SCM construction inspection course at NC State. - Maintenance and enforcement: Ownership of post-construction SCMs is generally expected to fall to homeowners associations or the property owner responsible for common open space; county staff said designs should avoid placing SCMs on individual house lots where possible. The draft includes enforcement options ranging from notices to civil penalties and injunctive relief; Durante discussion the county attorney noted civil penalties may be up to $25,000 per day for violations, and staff described a graduated enforcement process (letters, follow-up, referral to county attorney for enforcement actions when necessary).

Public and board questions Commissioners and members of the public pressed staff on several practical issues: how on-site quality performance is ensured (staff said designs follow accepted national performance assumptions, supported by as-built certification and inspection), whether homeowners associations reliably maintain SCMs (staff acknowledged historic problems and said annual inspections and enforcement remedies are intended to address that), how long approvals remain valid if a subdivision sits undeveloped (approvals expire if municipal/planning approvals lapse), and whether the county has capacity to implement inspection and enforcement (staff said they recently hired an additional inspector and were hiring another staff member).

Next steps County staff will take public input through August and return to the board Sept. 2 with the ordinance and design manual for possible adoption. If adopted, staff recommended Nov. 1, 2025 as the countywide implementation date; projects already in process may choose the older rules where eligible.

Excerpts from the hearing were recorded in the board transcript for the Aug. 4 session and submitted as part of the public record.

Ending note: The board asked staff to provide cross-references between presentation slides and ordinance sections to help commissioners and stakeholders review the many redlined changes before the Sept. 2 adoption vote.