Lacey, WA Environmental Rules: Flood Elevation Requirements (2026)

Elevation standards for the City of Lacey, Thurston County, Washington sit in LMC 14.34.130, titled Specific standards for pre-existing use exemptions. They apply in special flood hazard areas where base flood elevation data has been provided or can be reasonably obtained under LMC 14.34.030 or 14.34.100(B). Because LMC 14.34.082 prohibits new development in flood hazard areas, these standards govern substantial improvements to pre-existing structures and the few exempt new structures.

Residential: the lowest floor, including basement, must be elevated one foot or more above the BFE, and mechanical equipment and utilities must be waterproof or elevated at least one foot above the BFE. The improvement cannot increase the footprint of the structure and is not permitted in the floodway. In an unnumbered A zone with no available BFE, the structure must be reasonably safe from flooding and the lowest floor must be at least two feet above the highest adjacent grade. V, V1-30 and VE zone structures follow LMC 14.34.135.

Nonresidential: in AE and A1-30 zones, the lowest floor must be elevated one foot or more above the BFE, or as ASCE 24 requires, whichever is greater. A pre-existing nonresidential structure that does not meet that standard can instead be dry floodproofed to one foot above the base flood level, with certification by a registered professional engineer or architect.

Enclosures below the lowest floor must be designed with a minimum of two openings having a total net area of not less than one square inch for every square foot of enclosed area, with the bottom of all openings no higher than one foot above grade.

Documentation: the application under LMC 14.34.080 must show the lowest floor elevation on a current FEMA elevation certificate, and the building official records the as-built elevation under LMC 14.34.100(C). Variances from the elevation standard under LMC 14.34.110 are quite rare, and an applicant granted one is told in writing that the lowest floor will be below the BFE and that flood insurance will cost commensurately more.