Bethel, CT Environmental Rules: Stormwater Management (2026)

13 of the Bethel Zoning Regulations, effective 5-15-2025, applies to any new development or redevelopment received after the date of adoption, including any earth disturbance such as excavation, filling or grading, and any application subject to Planning and Zoning Commission review, including special permits, subdivisions and floodplain site plan applications. For residential zones, the trigger is specific: a residential project resulting in more than 1,000 square feet of new impervious coverage. Business, commercial and multi-family projects must submit a stormwater management plan whenever new impervious coverage is proposed, though the plan only has to address the new coverage area.

Subsection E requires a stamped, signed site plan from a Connecticut-licensed professional engineer showing that post-development runoff will not exceed existing conditions, following the design procedures in the Connecticut Stormwater Quality Manual. On water quality, treatment facilities must remove at least 80% of the average total suspended solids load and remove oils, greases and vehicle fluids to the maximum extent possible before runoff leaves the site. Peak-runoff attenuation must be demonstrated for the two-, 10-, 25- and 100-year storm events based on 24-hour storm duration, using NOAA Atlas 14 rainfall data, unless the Commission waives the criterion for sites discharging to a large river or lake.

Detention systems not dedicated to the Town require a filed maintenance agreement covering routine upkeep, the responsible party, Town inspection access and an emergency operation plan before a Zoning Certificate of Compliance can issue.