St. Louis County, MO Landscaping Rules: Composting (2026)

Section 607.1005 does two separate things: it places the pile, and it sets a standard for how the pile is run. The placement rule is both a distance and a direction. At least three feet behind the main residential structure means the measurement starts at the house, not at the lot line, so where a St. Louis County home sits on its lot determines where composting can legally begin. Because the rule pushes the activity behind the main structure, a compost pile in the front yard does not comply no matter how tidy it is.

The performance rule names three failure modes: odors, the harborage of rodents and pests, and the discharge of leachate onto neighboring properties. The section spells out leachate as the liquid the pile releases, so there is no argument about the term. Notably, the code does not prescribe a bin design, a temperature, or a turning schedule. It requires accepted methods, which in practice means turning and layering the material so it stays aerobic and so any liquid it produces stays on the composter's own ground rather than running downhill onto the neighbor's.

The prohibited list is short and specific: meat scraps, bones, fatty foods such as cheese and cooking oils, and pet waste. Those four categories are exactly the materials that produce the odor and rodent problems the performance rule forbids, so the list and the standard are two expressions of the same concern. Leaves, grass clippings, yard and garden trimmings, and vegetable scraps are the materials the program is built around, which is why a household can compost kitchen produce trimmings but not last night's chicken bones.

Compost piles also cannot be located in natural waterways or in man-made stormwater channels. That restriction protects the same drainage the leachate rule is aimed at: material sitting in a channel discharges directly into the system instead of breaking down in place.