Direct Answer
To hire a reliable septic system installation & replacement contractor in Seattle: (1) Get 3 written quotes with line-item breakdowns, (2) Verify WA license at Washington Labor & Industries (lni.wa.gov), (3) Confirm active general liability and workers' comp insurance, (4) Check Google and BBB reviews specific to Seattle projects, (5) Never pay more than 10-30% upfront — never pay in full before completion.
Full Explanation
Red flags specific to Seattle contractors: no physical Seattle-area address, pressure to start immediately, cash-only payment demands, and license numbers that don't verify at Washington Labor & Industries (lni.wa.gov). Seasonal demand during summer brings out less reputable contractors.
Local Factors in Seattle
📍Verify license: Washington Labor & Industries (lni.wa.gov)
📍File complaints: Washington Labor & Industries (lni.wa.gov)
📍Homeowner protections under WA consumer protection law
📍BBB Greater Seattle chapter for complaints history