11.19.060 General standards.
In all areas of special flood hazards the following standards are required:
(a) Anchoring.
(1) All new construction and substantial improvements, including those related to manufactured homes, shall be anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads including the effects of buoyancy.
(2) Manufactured homes and mobile homes shall be installed and anchored to prevent flotation, collapse or lateral movement, and shall be installed using methods and practices that minimize flood damage. Anchoring methods may include, but are not limited to, use of over-the-top or frame ties to ground anchors. Installation and anchoring standards are identified in Appendix A (Guidelines for the Installation and Anchoring of Manufactured Housing in Washington State).
(3) All components of the anchoring system shall be capable of carrying a force of four thousand eight hundred pounds.
(4) Any additions to a manufactured or mobile home shall be similarly anchored.
(b) Construction Materials and Methods.
(1) All new construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage.
(2) All new construction and substantial improvements shall be constructed using methods and practices that minimize flood damage.
(3) Electrical, heating, ventilation, plumbing, and air-conditioning equipment and other service facilities shall be designed and/or otherwise elevated or located so as to prevent water from entering or accumulating within the components during conditions of flooding.
(c) Utilities.
(1) All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems;
(2) New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems and discharge from the systems into floodwaters; and
(3) On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.
(4) Water wells shall be located on high ground that is not in the floodway.
(d) Subdivision Proposals.
(1) All subdivision proposals shall be consistent with the need to minimize flood damage;
(2) All subdivision proposals shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize flood damage;
(3) All subdivision proposals shall have adequate drainage provided to reduce exposure to flood damage; and
(4) Where base flood elevation data has not been provided or is not available from another authoritative source, it shall be generated for subdivision proposals and other proposed developments which contain fifty or more lots or exceed five acres in area.
(e) For new manufactured home parks, and manufactured home subdivisions; for expansion to existing manufactured home parks and manufactured home subdivisions; for existing manufactured home parks and manufactured home subdivisions where the repair, reconstruction or improvement of the streets, utilities and pads equals or exceeds fifty percent of the value of the streets, utilities and pads before the repair, reconstruction or improvement has commenced; and for manufactured homes not placed in a manufactured home park or manufactured home subdivision, require that:
(1) Individual lease spaces or lots are elevated on compacted fill or on pilings so that the lowest floor of the manufactured home will be at least one foot above the base flood level.
(2) Adequate surface drainage and access for a hauler are provided.
(3) In the instance of elevation on pilings, that:
(A) Individual lease spaces or lots are large enough to permit steps.
(B) Piling foundations are placed in stable soil no more than ten feet apart.
(C) Reinforcement is provided for pilings more than six feet above the ground level.
(f) Review of Building Permits. Where elevation data is not available either through the flood insurance study, FIRM, or from another authoritative source, applications for building permits shall be reviewed to assure that proposed construction will be reasonably safe from flooding. The test of reasonableness is a local judgment and includes use of historical data, high water marks, photographs of past flooding, etc., where available. Failure to elevate at least two feet above grade in these zones may result in higher insurance rates.
(g) Storage of Materials and Equipment.
(1) The storage or processing of materials that could be injurious to human, animal, or plant life if released due to damage from flooding is prohibited in special flood hazard areas.
(2) Storage of other material or equipment may be allowed if not subject to damage by floods and if firmly anchored to prevent flotation, or if readily removable from the area within the time available after flood warning. (Ord. 2129, § 2, 2021.)