15 Questions to Ask Before Hiring a Plumber

Questions About Credentials (Ask These First)

1. "What is your plumbing license number?"
   Any legitimate licensed plumber knows their number and provides it immediately. Verify it on your state licensing board website before scheduling.
2. "Are you insured? Can I see your certificate of insurance?"
   Request the actual COI — it should show general liability (minimum $1M) and workers' compensation coverage. Verbal confirmations are not sufficient.
3. "How long have you been licensed in this state?"
   Longer-established contractors generally have more stable businesses and more local experience with your area's specific code requirements.
4. "Do you use subcontractors? Are they licensed?"
   For large projects, know exactly who will be working in your home and confirm all workers are licensed and covered by insurance.

Questions About Pricing and Estimates

5. "Can I get a written estimate before you start?"
   Always yes. Verbal estimates are unenforceable and lead to billing disputes. Walk away if a plumber refuses to put the estimate in writing.
6. "Is the service call fee credited toward the job?"
   Some plumbers credit the diagnostic fee against your bill if you hire them; others charge it separately. This $50–$150 difference matters.
7. "What is your hourly rate and minimum charge?"
   Understand the billing structure before you approve work. Most plumbers have a 1-hour minimum.
8. "What could change this estimate?"
   Ask about scenarios that could increase cost — discovering additional issues once work begins, parts availability, or access difficulties. Understanding potential cost increases upfront prevents disputes.

Questions About Scope of Work

9. "Will this job require a permit? Who will pull it?"
   Licensed plumbers pull their own permits. If they ask you to pull it, that's a red flag suggesting they may not be properly licensed for the work.
10. "What is the exact scope of what's included in this quote?"
    Get the exact list of tasks and materials included. "Fix the drain" is not a scope — "snake the main drain line from the cleanout to 75 feet" is a scope.
11. "What will you need from me before and during the job?"
    Covers access requirements, shutting off utilities, clearing work areas, and who needs to be present.

Questions About Quality and Warranty

12. "What warranty do you provide on labor?"
    Industry standard is 1 year on workmanship. Get this in writing on your invoice.
13. "What brands of materials do you use?"
    For fixtures and parts, know whether you're getting name-brand (Kohler, Moen, Rheem) or generic materials. You can often supply your own fixtures to save money.
14. "Can you provide 2–3 references from similar jobs?"
    For large jobs ($1,000+), references are reasonable to request. A contractor who can't provide any references for recent similar work is a yellow flag.
15. "How do you handle problems that arise after the job is done?"
    Understand the process: who do you call, how quickly do they respond, what's covered under warranty and what isn't.

Red Flags: When to End the Conversation

Walk away immediately if a plumber:

According to the Bureau of Labor Statistics, there are approximately 480,600 plumbers employed in the United States with a median annual wage of $61,550. The U.S. EPA reports that household water leaks can waste nearly 10,000 gallons per year.

• Cannot or refuses to provide a license number
• Refuses to provide a written estimate
• Demands 50%+ upfront before any work begins
• Pressures you to decide immediately without time to compare quotes
• Asks you to pull the permit for work they're doing
• Has no business name, unmarked vehicle, and insists on cash only

More details: Red Flags When Hiring a Plumber and Complete Guide to Hiring a Plumber.

Frequently Asked Questions