Questions to Ask Plumber in Interview
Questions to ask a plumber before you agree to any work, from a slow drain to a repipe. They cover license and insurance you can verify, how the diagnosis was reached, what the quote includes and leaves out, permits, warranty terms and payment.
The questions
Open any question for the note
Are you licensed for this work here, and what is your license number?
Why ask it
Asking for the number rather than a yes is what makes it checkable, since most states publish a free lookup showing status and complaints. Hesitation over the number is the strongest signal to keep looking.
Do you carry liability insurance and workers' compensation, and can you have the certificates emailed to me?
Why ask it
Liability covers damage to your house; workers' compensation covers an injury to whoever is lying under your sink. Ask for certificates sent by the insurer rather than a photo of a card, because coverage lapses more often than licenses do.
What do you think is causing this, and how did you check?
Why ask it
The how matters more than the diagnosis. A camera, a pressure test, or listening at the meter are real checks, while a guess made from the doorway usually turns into an invoice for the wrong repair.
What are my options here, including the cheaper repair and the full replacement?
Why ask it
Almost every plumbing problem has a patch and a proper fix, and you should hear both prices. Someone who offers only the expensive option, or only the cheap one, is making a budget decision on your behalf.
Have you worked on houses of this age and this pipe material before?
Why ask it
Cast iron, galvanized steel, polybutylene and copper each fail in their own way, and older houses hide surprises. Someone familiar with your era of plumbing predicts what is behind the wall instead of discovering it at your expense.
Which parts and fixtures are you planning to use, and can I have the model numbers?
Why ask it
Fixture quality varies widely at similar prices, and some cheaper valves are hard to find parts for a few years on. Model numbers let you check them and confirm that what arrives is what was quoted.
Is this a fixed price, or an hourly rate plus materials?
Why ask it
The two behave very differently when a job runs long. If it is hourly, ask the rate, the minimum charge, and the markup on parts, since that markup is often where the real margin sits.
What is your call-out charge, and does it come off the bill if I go ahead?
Why ask it
Many companies charge to attend and diagnose. Whether that fee is credited against the repair changes which quote is genuinely cheapest, and it rarely gets mentioned unless you ask.
Does the price include cutting into and repairing walls, floors or ceilings?
Why ask it
This is the most common gap between a quote and a finished job. Plumbers routinely leave open drywall behind them, so settle now whether patching and paint are included or whether you are hiring someone else for it.
What would make this cost more once you open it up?
Why ask it
Invites the caveat before it arrives as a change order. Useful answers are specific: corroded fittings, an undersized vent, no shutoff valve, or something a previous owner did that is not to code.
Does this need a permit, and will you pull it in your name?
Why ask it
Permits matter at resale and at inspection, and unpermitted work can complicate an insurance claim later. It should be pulled by the contractor, because a homeowner-pulled permit moves the liability onto you.
Who will actually be doing the work: you, an employee, or a subcontractor?
Why ask it
The person holding the wrench is often not the person who quoted. Ask for names, and if subcontractors are used, ask whether they carry their own insurance rather than relying on the main company's.
How many days will you be here, and will you be running other jobs at the same time?
Why ask it
Two days of work with three other jobs in progress becomes a week in practice. Ask what time they plan to arrive, since trades commonly start elsewhere and reach you mid-afternoon.
How long will my water be off, and will I have a working toilet overnight?
Why ask it
The practical question about living in the house while the work happens. Ask before you agree to a start date, and check whether they cap lines at the end of each day.
What warranty covers your labor, and what covers the parts?
Why ask it
The two are usually different lengths, and a manufacturer's part warranty often still leaves you paying labor for the replacement. Get both periods written down rather than said at the door.
If the same problem comes back in six months, what happens?
Why ask it
This is where a warranty gets tested. Listen for whether the return visit is free, and whether the same plumber comes back or you rejoin the dispatch queue as a new call.
How much do you need before you start, and when is the balance due?
Why ask it
A deposit toward materials is normal; a large payment before anything begins is not. Tie the balance to completed work, and pay by a method that leaves a record rather than in cash.
Can you give me two customers you did similar work for in the past year?
Why ask it
Recent and similar are the words doing the work here. A glowing reference from ten years ago, for a different kind of job, says nothing about how the company operates now.
What can I do to keep this from happening again?
Why ask it
Most plumbers will answer generously: what not to put down a drain, what water pressure to hold, when to replace a braided supply hose. It is free advice with a direct effect on the next bill.
Can you put all of this in writing before you start: scope, price, parts and dates?
Why ask it
The written scope is your only protection when two memories disagree in a month. It should name the parts, the price, the exclusions, who repairs the walls, and roughly when the work will happen.
How to use these questions
Practical guidance for the conversation itself
Before anyone comes out
- Find your main shutoff valve and check that it actually turns. If it does not, that is the first repair whatever else is wrong.
- Take photos and a short video of the leak or blockage, with sound. Intermittent problems have a habit of hiding while a stranger stands there watching.
- Write down when it started, what makes it worse, and any work done on the house recently.
- Ask on the phone what the call-out charge is and whether it comes off the repair, before you book anyone.
Comparing quotes
Three quotes only help if they describe the same job, so give each plumber the same information and ask each to price the same scope. Read for what is excluded rather than for the headline number: wall patching, hauling away the old unit, permit fees, and whether fixtures are supplied by you or by them. A quote well below the others usually differs in scope or in parts, so ask which one it is. And if a plumber will not put a scope in writing, there is nothing to compare.
Warning signs
- Pressure to decide today, or a discount that vanishes if you get a second opinion.
- A demand for a large cash payment up front, or a request to pay a person rather than the company.
- Reluctance to give a license number, a business address, or insurance certificates.
- A diagnosis reached without opening, testing or even looking, followed straight away by the most expensive option.
- A quote that is one number and a signature line, with no scope attached.
In an emergency
- Shut the water off at the main, or at the fixture's own valve, before you call anyone.
- After-hours rates are real. Ask what the emergency rate is, and whether a temporary fix tonight with the full repair on a weekday would cost less.
- Photograph the damage before anything is cleaned up, in case you need to claim on insurance.
- You can still ask for a license number and a written scope at midnight, even if the price is not negotiable at that hour.