Direct Answer
The best septic system installation & replacement contractors in St. Louis are verified through Missouri Division of Professional Registration (pr.mo.gov). Look for companies with 4.5+ Google stars, 50+ reviews, active MO license, and at least 5 years serving the St. Louis area.
Full Explanation
Verify any St. Louis contractor at Missouri Division of Professional Registration (pr.mo.gov). Request proof of general liability insurance and workers' compensation. Ask for references from recent St. Louis projects — local experience matters for understanding permit requirements and area-specific challenges.
Local Factors in St. Louis
📍Verify license: Missouri Division of Professional Registration (pr.mo.gov)
📍St. Louis city permit office issues local permits
📍Check BBB Greater St. Louis chapter
📍Require MO state license + local city license if applicable