Environmental Rules in Caldwell, ID (2026)
5 verified environmental rules for Caldwell, Idaho, sourced directly from the municipal code and official government pages.
Verified from official government sources
Stormwater Management
Any Caldwell development disturbing one acre or more must have a Stormwater Pollution Prevention Plan approved by the Caldwell Stormwater Division before a grading permit issues, and the developer must separately secure Construction General Permit coverage from the Idaho Department of Environmental Quality.
Caldwell, Idaho Stormwater Pollution Prevention Plan
Some RestrictionsCaldwell City Code § 04-19-09
(1) Contents: The stormwater pollution prevention plan (SWPPP) shall include: A. A sequence of construction of the development site, including stripping and clearing, rough grading, stockpiling, construction of utilities, infrastructure, and buildings, and final grading and landscaping. Sequencing shall identify the expected date on which clearing will begin, the estimated duration of exposure ...
Erosion Control
Any construction or land-disturbing project affecting one acre or more inside Caldwell city limits must obtain a grading permit from the Caldwell Stormwater Division and follow the design criteria in the state's erosion field guide. Cut and fill slopes cannot exceed a 3:1 ratio, and disturbed soil must be stabilized within ten days of clearing or of work going idle.
Caldwell, Idaho Erosion and Sediment Control
Some RestrictionsCaldwell City Code § 04-19-11
Grading, erosion control practices, sediment control practices, and waterway crossings on all construction sites, and all other activity governed by this article, shall meet the requirements of this article and the design criteria set forth in the most recent version of the "Idaho Construction Site Erosion And Sediment Control Field Guide", and shall be adequate to prevent transportation of sed...
Flood Zones
Caldwell's FP-1 Floodplain Overlay Zone covers FEMA-designated flood hazard areas along the Boise River and requires a floodplain development permit before construction, while Section 12-15-05 bars new structures in the mapped floodway and fines violators, under City Code Section 10-11-06-1.
Caldwell Floodplain Overlay Zone Rules
Significant RestrictionsCaldwell City Code § 10-11-06-1
10-11-06-1: FP-1: FLOODPLAIN OVERLAY ZONE: ... (2) Location: ... The boundaries of the FP-1 Floodplain overlay zone shall be the special flood hazard areas designated as zones A and AE by the federal emergency management agency in its flood insurance study (FIS) for Canyon County, Idaho, and incorporated areas, dated May 24, 2011, with accompanying flood insurance rate maps (FIRM) or digital ...
Boat Dock Permits
Caldwell treats docks, piers, boat ramps and marinas as floodway obstructions: any such structure with the potential to obstruct flow and encroach into a mapped regulated floodway must clear the same no-rise encroachment test as any other floodway development under Caldwell City Code § 12-15-09, enforced by the city's Floodplain Administrator.
Caldwell Floodway Dock And Pier Rule
Significant RestrictionsCaldwell City Code § 12-15-09(2)J.5, (5)A
5. Docks, piers, boat ramps, marinas, moorings, decks, docking facilities, port facilities, shipbuilding, and ship repair facilities with potential to obstruct flow and encroach into regulated floodways shall meet the limitations of subsection (5) of this section. ... (5) Standards For Floodways: Areas designated as floodways located within the special flood hazard areas established in subsec...
Flood Elevation Requirements
Caldwell's floodplain ordinance requires new residential construction in a mapped special flood hazard area to elevate its lowest floor, including any basement, no lower than the flood protection elevation, which equals the FEMA base flood elevation plus a one-foot freeboard margin. The Floodplain Administrator enforces the standard under Caldwell City Code § 12-15-09.
Caldwell Base Flood Elevation Freeboard Rule
Some RestrictionsCaldwell City Code §§ 12-15-03, 12-15-09(2)A
FREEBOARD: ... A factor of safety usually expressed in feet above a flood level for the purposes of floodplain management. ... The base flood elevation (BFE) plus the freeboard establishes the flood protection elevation (FPE). Freeboard shall be one foot (1'). ... ... A. Residential Construction: New construction, substantial improvements, and development of any residential structure (including...
Looking for Canyon County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Caldwell city rules.
Environmental Rules in Canyon County →