Plumbing is one of the few home services where unlicensed work can literally ruin a house sale. Unpermitted plumbing work shows up in home inspections, can void homeowner's insurance, and creates personal liability if a water leak damages a neighbor's property. Here's how to verify before you hire.
Step 1: Verify the License with Your State Board
Every US state has a licensing board for plumbers. In Texas: Texas State Board of Plumbing Examiners (TSBPE) at tsbpe.texas.gov. In California: Contractors State License Board (CSLB) at cslb.ca.gov. In Florida: Department of Business and Professional Regulation at myfloridalicense.com. Search the plumber's name or license number and verify it shows as active, not expired or suspended.
Step 2: Confirm Insurance
Ask for a Certificate of Insurance showing: General Liability (minimum $500,000 coverage) — protects your property from accidental damage. Workers' Compensation — covers injuries to workers on your property. Call the insurance carrier directly to verify the certificate is current — fraudulent COIs are not uncommon among unlicensed contractors.
Step 3: Get 3 Written Quotes
Plumbing prices vary 20–40% between contractors for the same scope of work. A written quote should include: itemized scope of work, materials specified by brand/type, labor cost separately from materials, permit fees (if applicable), timeline, and warranty terms. Avoid any contractor who quotes verbally only or who pressures you to sign same-day.
5 Red Flags to Walk Away From
1. No physical business address (PO Box only). 2. Quote is dramatically lower than others (often means unlicensed labor or low-quality materials). 3. Asks you to pull the permit yourself. 4. No insurance certificate or won't provide one. 5. Demands full payment upfront.