7 Del. Admin. Code § 7103-26.0
Sufficient storage capacity must be provided for the maximum amount of wastewater generated over the maximum length of time for which irrigation is impractical. Non-application periods depend primarily upon the climate (e.g., excess soil moisture due to precipitation; freezing conditions) and the crop grown (e.g., crop growth stages that prohibit wastewater application). The storage facility capacity must consider a minimum reserve volume, rainfall storage for the design storm, volume for sludge accumulation and storage for non-application periods such as crop harvest and establishment, inclement weather, frozen soil, equipment breakdowns and flow equalization to name a few. The storage facility should be constructed properly to preclude seepage to groundwater and to preclude overflow except when rainfall exceeds design basis, in which case the possible impact of potential overflow must be considered.
7 Del. Admin. Code § 7103-26.0