Council adopts Phase 2 stormwater amendments, raising permit trigger to 0.5 acre outside downtown

The Black Mountain Town Council adopted Phase 2 amendments to the town’s post‑construction stormwater ordinance, changing how projects trigger town stormwater permits and clarifying inspection and maintenance responsibilities.

Planning and stormwater staff said the town’s existing ordinance created an administrative burden by applying strict requirements to many small, single‑family projects. The revised ordinance replaces an impervious‑surface threshold with a disturbance threshold: projects that disturb one half acre or more will now trigger a town stormwater permit in most zoning districts; disturbance of one acre or more will trigger a permit in the Central Business District. The change aligns the town’s rules with state practice and the town’s NPDES (National Pollutant Discharge Elimination System) permit.

Under the new rules, projects will be categorized as low‑ or high‑density according to state code (high density: built‑upon area ≥24 percent). Low‑density stormwater permit sites will be inspected by town staff once per NPDES permit cycle (five years); high‑density sites will be inspected twice per cycle. Permit holders must continue annual self‑inspections and maintain an operations and maintenance (O&M) agreement; those annual reports will be kept on‑site rather than required to be routinely submitted to the town unless requested.

Stormwater staff said the town will continue to require that structural control measures (SCMs) meet design standards. To reduce homeowner costs, the ordinance allows owners to use a certified SCM inspector (an NCSU‑certified inspector) or to take the course themselves (staff said the course historically costs about $250 and takes roughly a day and a half, including a test). Staff said the change would free staff time to pursue voluntary, basin‑scale green infrastructure projects that engineers expect will yield measurable water‑quality benefits.

The planning board reviewed the amendments and recommended unanimous approval; the council adopted the changes at the meeting.

Ending: Staff said the changes aim to reduce administrative burden on small property owners while focusing enforcement and staff resources on larger projects and basin‑scale resilience work. The town will publish updated guidance and begin implementing the revised inspection schedules.