Johnston County adopts revised stormwater ordinance, effective Jan. 1, 2026, after hours of debate

The Johnston County Board of Commissioners voted 4–3 on Sept. 2 to adopt revisions to Article 7 (Stormwater Management) of the county Land Development Code, setting new design standards, inspection requirements and exemptions for small subdivisions. The board set an effective date of Jan. 1, 2026.

County Utilities Director Chandra Farmer presented the ordinance revisions, which staff and stakeholders have worked on since 2020. Farmer told commissioners the revisions respond to state stormwater requirements, an agreement with the U.S. Fish and Wildlife Service and local concerns about downstream flooding and water-quality impacts. Key changes include a recommended minimum built-upon area of 6,000 square feet for new residential lots not served by public sewer; a change in required attenuation design storms to 1-in-25 years in most areas and 1-in-100 years in the Middle Creek/environmentally sensitive area under the Fish and Wildlife agreement; and exemptions from attenuation for subdivisions of 19 lots or fewer if the post-development runoff increase is less than 8 percent.

Farmer said the 6,000-square-foot minimum was a staff analysis intended to give future homeowners reasonable room to add driveways, garages or outbuildings without triggering costly post-plat compliance problems. She told the board that engineers and developers had sometimes designed lots to very low built-upon-area limits—2,500 to 3,000 square feet—so the homeowner was effectively constrained in future use.

The ordinance removes the countys existing land-dedication in-lieu program that previously had been triggered when subdivisions exceeded specified impervious-area thresholds (12 percent in environmentally sensitive areas, 15 percent elsewhere). Farmer said the county had used some land-dedication funds for conservation easements but that the mechanism rarely produced protection in the same watershed as the development; the new on-site attenuation requirement is intended to provide localized protection.

The county will require annual inspections and certifications of stormwater control measures by qualified professionals, with inspection reports submitted to the county. Farmer said the county will record operation-and-maintenance agreements in the register of deeds at final plat to identify the responsible party (HOA or other entity). Commissioners and staff acknowledged that many HOAs and small subdivisions lack capacity or funds to maintain engineered stormwater facilities; several commissioners urged that the county build an enforcement program and public education to ensure maintenance compliance. County legal counsel explained enforcement tools include the usual code-enforcement steps and, if needed, court-ordered remediation with liens for costs if the county must complete required work.

Developers and the Johnson County Building Industry Association asked the board to delay adoption to allow more time to review the ordinance language; industry representatives and local homebuilders raised concerns about potential per-lot costs and longer-term HOA obligations. Several commissioners and staff said they had received written comments in the seven days prior to the meeting after a multi-year public process during which the revisions had been posted, presented at stakeholders meetings and discussed at the planning board.

After extended discussion about timing, coordination with the countys pending Unified Development Ordinance (UDO) and staff capacity to implement and enforce the new rules, the board voted 4 in favor and 3 opposed to adopt the revisions. The motion adopted the ordinance language as presented and set Jan. 1, 2026, as the effective date to allow time to align code recodification and administrative checklists.

Commissioners and staff said they expect continuing stakeholder engagement and that the county will revisit and amend the ordinance as necessary after staff gains implementation experience and collects data from inspections and complaints.

The new ordinance text and related design-manual revisions will be posted on the county website and will apply to new development in the county planning jurisdiction on or after the effective date; developments with planning-board approval submitted before the effective date will remain subject to the prior rules, staff said.