Choosing a plumber: the questions that separate a good one from a costly one

What a good plumber does that a bad one does not

Choose a plumber who holds a current Texas plumbing license you can verify, who diagnoses the problem before quoting a price, who gives you options in writing with the reasons behind each, and who quotes the job rather than the hour. Then ask what the warranty covers and who will actually do the work. A company that answers those questions clearly on the phone is usually the one that does the job right.

I run 1-800 Plumber +Air in the Dallas area, and I would give you this advice even if you never call us. Most bad plumbing experiences I hear about did not start with poor workmanship. They started with a homeowner who did not know what to ask, accepted a single option, and found out what the job really involved after the bill arrived.

Start with the license, and look it up yourself

In Texas, plumbing is a licensed trade regulated by the Texas State Board of Plumbing Examiners. The board issues several license types, including Master Plumber, Journeyman Plumber and Tradesman Plumber-Limited, along with apprentice registrations. Its consumer message is short and worth repeating: always hire a licensed plumber.

You do not have to take anyone's word for it. The board's website has a public license search where you can enter a name or license number and see whether the license is current. A legitimate company will give you its number without hesitation. Ours, for example, is RMP M-44764, held by our master plumber, Dennis Collins. If a company cannot or will not give you a number, that tells you what you need to know.

Ask, too, who will be in your house. A master plumber may hold the company license while journeymen and apprentices do much of the work, which is normal. What you want to know is that the people doing the work are licensed or registered and properly supervised, and that the crew works for the company rather than an unnamed subcontractor.

Insurance, paperwork and what to keep

A license is the minimum. Ask whether the company carries liability insurance and whether its workers are covered, and do not be shy about asking for proof on a larger job. If a technician is hurt in your attic or a pipe joint fails and floods a room, you want that to be the company's problem, not yours.

Then keep the paperwork. A good plumber leaves you a written invoice that describes what was found, what was done, which parts were installed and what the warranty covers. For a water heater, keep the model and serial number and the manufacturer's warranty card. For a sewer or leak repair, ask for the camera footage or photos. These records matter if a problem returns, if you file an insurance claim, or when you sell the house and a buyer's inspector asks what has been updated.

If something does go wrong and the company will not make it right, the Texas State Board of Plumbing Examiners accepts consumer complaints through a form on its website. I hope you never need it, but it is good to know it is there.

Questions worth asking on the first phone call

A five-minute call tells you a lot. Listen for whether the person answers directly or keeps steering you toward booking without answering. These are the questions I would ask.

• What is your Texas plumbing license number, and who holds it?
• Do you price by the job or by the hour, and when will I see the price?
• Is there a trip charge or diagnostic fee, and is it credited toward the repair?
• Do you charge more for nights, weekends or holidays?
• Will the technician explain more than one option if there is one?
• What warranty do you give on labor, and is it in writing?
• Will someone call ahead to confirm the arrival time?

A diagnosis should come before the number

The single biggest difference between plumbers is what happens before the price. A careful plumber looks, tests and explains. For a drain problem that keeps coming back, that means a camera inspection of the line so you can see the pipe yourself. For a water heater, it means finding out whether the problem is a part or the tank. For a hidden leak, it means locating it with equipment rather than opening walls to search. Our leak detection work uses tools such as infrared cameras, moisture meters and tracer gas for exactly this reason.

Be wary of a full replacement quote given over the phone or from the driveway. Be equally wary of the opposite: a plumber who keeps offering one more cheap fix on a problem that has returned three times. Both skip the diagnosis. If you want to see what a proper sewer evaluation looks like, my guide on failing cast iron sewer lines in older homes walks through the camera-first approach step by step.

Comparing two quotes that do not match

When quotes for the same job are far apart, do not assume the cheaper one is a bargain or the expensive one is padded. Line them up and check whether they describe the same work. One may include a permit, haul-away, new valves and patching, while the other leaves them out. One may repair a section while the other replaces the whole line. One may be a firm job price and the other an hourly estimate that can grow.

Ask each company to explain its scope in plain words and to put it in writing. If one plumber says a repair will do and another says replacement, ask each why, and ask to see the evidence: camera footage, a photo, a pressure reading. The plumber whose reasoning holds up under questions is the one to trust. If you are weighing water heater quotes in particular, my guide on what moves the price of a water heater replacement lists what a complete quote should include. For plumbing that is part of a larger remodel, a builder's guide on comparing three remodel bids is worth reading too.

Red flags that should end the conversation

Most plumbers are honest, hardworking people. A few habits, though, should make you slow down or walk away, no matter how good the price sounds.

• No license number, or a number that does not show up in the state search
• A price for major work given without any inspection
• Pressure to decide on the spot, or a discount that expires when the technician leaves
• Only one option offered, with no explanation of alternatives
• Cash only, or payment in full before work begins
• A vague invoice with no description of the work done
• Blaming every problem on the last plumber without showing evidence

How to read reviews for what actually matters

Star ratings help, but the text tells you more. Look for reviews that describe the kind of job you need, not just a friendly technician. Did the plumber show up when promised? Did they explain the problem and give options? Did the final bill match the quote? Did they clean up? Those details predict your experience better than the number of stars.

Pay attention to how a company handles the occasional unhappy customer too. A thoughtful reply that addresses the problem is a good sign. And give weight to reviews from people with homes like yours. A company that regularly works on older houses with original pipe will understand the surprises those homes hold.

Finally, ask the people around you. A neighbor who just had a sewer line replaced, a home inspector who sees plumbers' work every week, or a property manager who calls plumbers for dozens of units has a far better sense of who is reliable than any advertisement. Ask them not only who they used, but whether they would call that company again and why.

Bigger jobs deserve a few extra questions

A dripping faucet does not need a long interview. A sewer replacement, a repipe or gas line work does. For these, ask how the job will be done and in what order, how long the water or gas will be off, how the company will protect floors and landscaping, what restoration is included, and how the work will be tested before it is closed up. Ask whether permits and inspections apply and who handles them.

Gas work deserves special care. A gas line should be installed and tested by a licensed plumber, and you should never accept a vague answer about how it was tested. Many of the costly problems I see started with homeowners believing something that sounded reasonable but was not; I collected the most common ones in a guide to plumbing myths that end in a repair bill.

How we try to earn the job

We hold ourselves to the same list. We price by the job, not by the hour, and we do not up-charge for nights, weekends or holidays. We call ahead to confirm the arrival time. Our technicians diagnose first, explain what they find, and lay out the options before any work begins, and our stated commitment is never to sell a customer something that is not needed. All of our work is guaranteed, and a full cast iron sewer replacement carries a three-year warranty.

We are locally owned and serve homes and businesses across Dallas, the Park Cities and the northern suburbs. If you call us and we are not the right fit, we will tell you. Either way, ask the questions on this page. A good plumber will be glad you did.

Questions people ask me