Bristol, CT Environmental Rules: Flood Elevation Requirements (2026)

Section 5.3.1(a) of Appendix D, Flood Damage Prevention, sets Bristol's freeboard standard: in every area of special flood hazard where base flood elevation data exists, new construction or substantial improvement of a residential structure must have its lowest floor, including any basement, elevated at least one foot above the base flood elevation (BFE), and all electrical, plumbing, machinery and other utility equipment serving the structure must likewise sit at or above the BFE. Section 5.3.2(b) applies the same one-foot-above-BFE floor to new or substantially improved commercial, industrial and other nonresidential structures in Zones A1-30, AE and AH, but lets the owner flood-proof instead of elevate if a registered professional engineer or architect certifies the design is watertight and can resist hydrostatic and hydrodynamic loads.

Elevated buildings with enclosed space below the BFE must be built to let floodwaters equalize automatically, either under an engineer's certification or by meeting minimum criteria under § 5.3.3: at least two openings totaling one square inch of net area per square foot of enclosed space, with the bottom of every opening no higher than one foot above grade, and no electrical or plumbing connections below the BFE. Above-ground fuel storage tanks must be elevated above the BFE on a concrete pad or anchored with tie-downs, with the fill pipe extended above the BFE and a screw cap that keeps floodwater out (§ 5.1.12).

Manufactured homes placed for 180 days or more face the same one-foot-above-BFE elevation on a permanent, anchored foundation (§ 5.1.8(a)). The city engineer verifies the as-built lowest-floor elevation before issuing a certificate of occupancy (§ 4.2.4).