St. Louis County, MO Public Health Rules: Rodent Control (2026)

Section 602.050 of the St. Louis County Code, 'Declaration of Nuisances,' lists conditions 'declared to be public nuisances affecting health,' making it 'a violation of this section to maintain or allow' them. Item (12) of that list covers 'All infestations of flies, fleas, roaches, lice, ticks, rats, mice, fly maggots, mosquito larvae and hookworm larvae,' putting a rodent problem in the same category as stagnant water, unburied animal carcasses, and garbage cans that are not fly-tight under the same section. The chapter's catch-all clause, item (15), reaches 'all other things detrimental or certain to be detrimental to the health of the inhabitants of the unincorporated portion of St. Louis County,' tying the nuisance code to the county charter's limit on the county's public health legislative power to the area outside incorporated cities.

The Director of Health enforces this directly. Section 602.020 gives the Director power to 'administer those programs authorized by ordinance for the control of weeds, rats and mosquitoes' and, separately, to inspect 'all buildings, lands, and places as to their conditions for health and sanitation' whenever the passage of time, the condition of an area, or probable cause of a violation warrants it. If an owner refuses entry, the Director must first secure a warrant from an associate circuit judge before inspecting. Under Section 602.070, the Director can require any 'owner, occupant, permit holder, tenant or employee' to furnish facts or records relevant to a nuisance investigation.

A conviction under Section 602.080 carries a fine of not less than $5 and not more than $300, imprisonment in the county jail for three to 90 days, or both, for each violation of the chapter or of any rule the Director adopts under it.