HireContractor
ElectricianPlumberHVAC ContractorRoofing ContractorPainting ContractorWater Damage RestorationFoundation RepairConcrete ContractorFence ContractorFlooring ContractorLandscaping ContractorSolar InstallerSiding ContractorWindow ContractorMold RemediationGarage Door ContractorAll 42 Trades →

Hiring a Plumber? 10 Questions to Ask First

A plumbing mistake doesn't just cause an inconvenience -- it can flood your basement, contaminate your drinking water, or create mold problems that cost tens of thousands to remediate. The difference between a qualified plumber and an unqualified one often isn't visible until something fails. Before you sign anything, run through this checklist to confirm the plumber diagnoses problems correctly, uses appropriate materials, and stands behind their work.

10 QuestionsPrintable ChecklistAvg Cost: $175 - $600 per job

Questions to Ask

1Are you a licensed plumber in this state, and what type of license do you hold?

Why It Matters

Most states distinguish between apprentice, journeyman, and master plumber licenses. Only a master plumber can typically pull permits and supervise work independently.

Red Flag

They hold a general contractor license but not a specific plumbing license, or they cannot tell you their license type.

Pro Tip

A master plumber who will be on site for your project is ideal. If a journeyman does the work, confirm a master plumber is supervising and available.

2Will you use a camera inspection to diagnose the problem before quoting a repair?

Why It Matters

Sewer line issues, hidden leaks, and drain problems often have multiple possible causes. A camera inspection gives visual confirmation of the actual problem instead of expensive guesswork.

Red Flag

They diagnose a sewer line problem without a camera and immediately recommend the most expensive repair option.

Pro Tip

A camera inspection typically costs $100-$400 and can save you thousands by pinpointing the exact location and nature of a blockage or break.

3Do you offer trenchless repair options, and when is trenchless appropriate versus traditional excavation?

Why It Matters

Trenchless sewer repair (pipe lining or pipe bursting) avoids destroying your landscaping, driveway, or foundation. But it's not suitable for every situation -- collapsed pipes or certain materials may require excavation.

Red Flag

They only offer one method (either always trenchless or always excavation) without evaluating your specific pipe condition.

Pro Tip

A plumber who explains both options and recommends based on the camera inspection findings is making decisions based on your situation, not their equipment inventory.

4What type of pipe material will you use, and why?

Why It Matters

PEX, copper, CPVC, and PVC each have different lifespans, costs, and code requirements depending on application. The wrong material in the wrong place can fail prematurely or violate code.

Red Flag

They use the cheapest option without discussing alternatives, or they plan to use a material not approved for your application in your jurisdiction.

Pro Tip

For water supply lines, PEX is now the most common choice for its flexibility and corrosion resistance. For drain lines, PVC or ABS is standard. Copper remains preferred for gas lines in many jurisdictions.

5Will you pull the necessary permits, and who handles the inspection?

Why It Matters

Plumbing permits are required for most work beyond simple fixture swaps. Unpermitted plumbing can fail a home inspection, void insurance claims, and create code violations you inherit.

Red Flag

They suggest skipping the permit or claim the work is too minor to require one without checking your local requirements.

Pro Tip

Ask them to include the permit fee in the written estimate. A plumber who regularly permits their work has an established relationship with your local building department.

6How do you handle unexpected problems discovered during the job, and how does that affect pricing?

Why It Matters

Plumbing often reveals surprises behind walls or underground. Without an agreement about change orders, you can face large unexpected bills with no leverage.

Red Flag

They have no change order process and expect verbal approval for additional costs, or the contract has no language about scope changes.

Pro Tip

The best approach is a written change order process: the plumber stops work, documents the issue, provides a written cost adjustment, and gets your signed approval before proceeding.

7Do you guarantee your work, and what does the warranty cover?

Why It Matters

If a connection leaks two months after installation, you need to know whether the plumber will come back at no charge. Labor warranties are separate from manufacturer warranties on fixtures and parts.

Red Flag

No written warranty, or a warranty that excludes common failures like joint connections or fittings.

Pro Tip

A one to two year labor warranty is standard for quality plumbers. Some offer longer warranties on major work like whole-house repiping or sewer line replacement.

8Are you insured for water damage that results from your work?

Why It Matters

Plumbing work carries a higher risk of water damage than most trades. A burst connection can cause thousands in damage to flooring, drywall, and personal property.

Red Flag

They carry general liability but with exclusions for water damage, or their coverage limits are too low for the potential damage.

Pro Tip

Request a certificate of insurance showing at least $1 million in general liability coverage. Confirm it covers water damage resulting from completed operations.

9What is your backflow prevention approach for this project?

Why It Matters

Backflow prevention keeps contaminated water from flowing backward into your clean water supply. Many jurisdictions require annual backflow testing, especially for irrigation systems and commercial properties.

Red Flag

They are unfamiliar with local backflow requirements or dismiss the question as irrelevant to your project.

Pro Tip

If you have an irrigation system, fire sprinkler system, or commercial kitchen, backflow prevention isn't optional. Ask whether your existing backflow device needs testing or replacement.

10Can you provide references from three recent jobs similar to mine?

Why It Matters

A plumber who excels at drain cleaning may not have experience with whole-house repiping. References from similar projects confirm they have relevant experience.

Red Flag

They cannot provide any references, or all references are from jobs that are significantly different from yours.

Pro Tip

Call the references and ask specifically: Did the plumber finish on time? Were there surprise charges? Did they clean up after themselves? Would you hire them again?

Bonus Tips for Hiring a Plumber

  • For emergency plumbing, know where your main water shutoff valve is before calling. Shutting off water immediately limits damage and gives you time to choose a plumber rather than accepting the first one available.
  • Ask whether the quoted price includes cleanup and disposal of old materials. Some plumbers leave old pipes, fixtures, and debris for you to handle.
  • If your home was built before 1986, ask about lead pipe and solder testing. Lead service lines and lead solder are still present in millions of older homes.
  • For water heater replacement, ask about energy efficiency ratings and whether a heat pump water heater might qualify for tax credits or utility rebates in your area.

Find Licensed Plumbers Near You

Browse verified plumber contractors in your area. Listings include license numbers and customer reviews where available.

Search PlumbersPlumber Directory

More Plumber Resources

Plumber DirectoryBrowse all plumber contractorsPlumber Cost GuideAverage pricing: $175 - $600 per jobAll Hiring GuidesChecklists for all 42 trades

Related Trade Guides

Water Damage RestorationSeptic ContractorWaterproofing Contractor
Get Free Quotes