Ada County, ID Landscaping Rules: Composting (2026)

Solid waste Chapter 5-2 treats backyard composting as a sanitary-condition issue rather than a zoning use. Section 5-2-4-2(E) states flatly that composting is permissible, and that compost or the matter used to make it may be transported, kept, and used, provided it does not constitute a public nuisance. The same subsection identifies three separate categories the county regulates differently: agricultural service composting, commercial composting facilities, and private composting, all cross-referenced to the definitions in Section 5-2-3. Private composting there is defined narrowly: producing compost, not for sale, on a parcel under five acres, capped at 10 cubic yards on-site at any one time, and used only on the same premises where it is produced.

Exceeding that 10-cubic-yard cap, or composting for sale, pushes the activity out of the private composting definition and into the commercial composting facility category, which triggers a different set of standards under Section 8-4-14, including Central District Health Department approval and a 100-foot setback from any residential district or use. The nuisance standard in Section 5-2-4-2(A) backs this up: no one may let waste, including compost material, accumulate on a property, public or private, in a way likely to attract flies or fly breeding, harbor rodents and pests, or create noxious or offensive odors, and doing so is treated as a public nuisance under Idaho Code Title 18, Chapter 59.

Compost material is also explicitly carved out from the county's fertilizer restrictions under Section 8-4-14(E), so a backyard compost pile is not treated as a regulated soil amendment.