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