Questions to Ask Before Hiring a Plumber

You’ve got water creeping across the basement floor, a drain that’s been gurgling for three days, or a water heater that sounds like it’s giving up. You need a plumber. But calling the first name that pops up on Google is a gamble. Plumbing work can go wrong in expensive ways — water damage, code violations, work that has to be redone. A few well-placed questions before you hire can save you thousands.

I’m Chris Lee. I’ve written plumbing estimates, read them from the homeowner side, and seen what happens when people skip the vetting process. Here are the questions to ask before hiring a plumber — organized so you can use them on the phone, in an email, or standing in your damp basement.

If the problem is active right now, do the safe basics first: find the shutoff, stop the water if you can, and read what to do when water is leaking from the ceiling before the call turns into a full damage-control job.

Start here: what the plumber should ask you first

Before you fire off questions, notice how the plumber handles the initial conversation. A good plumber will ask you questions first — they want to understand the problem so they can show up with the right tools and the right expectations.

A thorough plumber will ask about: when the problem started, whether it’s gotten worse, what you’ve already tried, visible damage (water stains, rust, mold), changes in water pressure or temperature, whether the issue affects one fixture or multiple, and whether the shut-off is accessible.

That last detail matters. If you do not know where the valve is, use the guide to finding your main water shutoff valve before the plumber arrives.

If the issue is pressure-related, write down whether the problem affects hot water, cold water, one fixture, or the whole house. That makes it easier to separate simple fixture trouble from the bigger causes covered in our low water pressure guide.

If a plumber jumps straight to scheduling without asking any of these, it doesn’t mean they’re bad — but it means you’ll need to be more thorough on your end.

Safety first: licensing, insurance, and bonding

This is the non-negotiable section. Do not skip it. Ask these three questions before anything else.

Are you licensed?

Plumbing licensing is regulated at the state level, and requirements vary widely. Some states require a master plumber license for work over a certain dollar amount. Others require only a business license. A few have no statewide licensing at all.

What to do: Ask for the license number and verify it through your state licensing board’s online lookup tool. Check that it’s active and look for any disciplinary history or complaints. A legitimate plumber expects this and will provide their license number without hesitation.

Red flag: The plumber who says “I’m licensed” but can’t produce a number, or whose number doesn’t match the state registry. Also be aware that in some areas, a “handyman” can legally do plumbing work under a certain dollar threshold — but that doesn’t mean they carry the insurance or training you want behind your walls.

Are you insured?

This question protects you, not the plumber. If a plumber damages your property — punctures a pipe inside a wall or starts a small fire with a torch — their insurance pays for repairs. If they don’t have insurance, you’re paying out of pocket or fighting a lawsuit.

General liability insurance covers property damage. Workers’ compensation insurance covers injuries to the plumber or their crew while on your property. If an uninsured plumber gets hurt in your home, you could be held financially responsible.

What to do: Ask for a certificate of insurance (COI). This standard document lists policy limits, effective dates, and the type of coverage. A reputable plumber will email you one in minutes or carry a copy in their truck.

Red flag: The plumber who says they’re insured but can’t or won’t produce a COI. Always check the effective dates — a lapsed policy is no policy at all.

Are you bonded?

A surety bond protects you if the plumber fails to complete the job, violates the contract, or skips required permits. Not every state requires bonding, and not every plumber carries one. For small jobs under $1,000, bonding matters less. For major work — a whole-house repipe or sewer line replacement — it’s worth asking.

For sewer work, ask whether a camera inspection is included or billed separately. A good scope should explain when a sewer camera inspection is useful and when the red flags point to a larger main-line problem.

Vetting questions: experience and track record

Once you’ve confirmed the basics, dig into their specific qualifications for your job.

How much experience do you have with this type of job?

Plumbing is a broad trade. The plumber who’s excellent at clearing drains may have limited experience with tankless water heaters or old-house repipes. Match their experience to your specific problem.

Water heater work is a good example. If that is the job, compare their answer against what a complete water heater replacement quote should include.

Good answer: “I’ve done about 40 water heater replacements this year.” Fine answer for simple jobs: “I can handle that.” For complex work, push for specifics.

Who will actually be doing the work?

You may be talking to the owner who will hand the job off to a journeyman or apprentice. That’s normal — but you should know who’s coming to your home and their experience level. Ask: “How long have they been with your company? Are they licensed in their own right?”

Can you provide references for similar work?

For jobs over $1,000, ask for references from customers who had similar work done in the last year. Call them and ask: Was the work completed on time and on budget? Were there unexpected costs, and how were they communicated? Did the crew clean up? Would you hire them again?

Red flag: A plumber who can’t provide references for large jobs, or only offers references from years ago.

Pricing questions: how you’ll be charged

A good plumber is used to pricing questions. If they get defensive, that’s a yellow flag.

If you already have a written number in front of you, compare it against the line items in our guide to reading a plumbing estimate before you approve the work.

Do you charge a service call or diagnostic fee?

Most plumbers charge $50-$150 just to come look at the problem. This is normal. Ask if that fee is credited toward the repair if you hire them. And ask if the fee changes based on time of day or day of the week.

Emergency work is a different conversation. If water is actively spreading or a sewer line is backing up, review the factors that change emergency plumber costs so you know why the bill may jump.

Is this flat-rate or time and materials?

Flat-rate: One price for the whole job. The plumber absorbs the risk if it takes longer. Fair for standard jobs like water heater swaps, toilet replacements, and drain clearing.

Time and materials (T&M): You pay actual hours plus parts with a markup. Fair for diagnostic work or jobs with an unclear scope — as long as there’s a not-to-exceed (NTE) cap so you’re not writing a blank check.

Red flag: T&M without an estimated range or NTE cap. Also watch for hourly rates dramatically above the local average ($50-$150 is typical for a licensed plumber).

What’s included and what’s not?

This is where most disputes start. A price sounds fair until you realize it doesn’t include permits, disposal of the old unit, or cleanup.

Ask: “Does this price include permits, disposal of old materials, and post-work testing? What would trigger a change order? What are the most common add-ons for this type of job and how much do they usually run?”

What are your payment terms?

For small jobs under $500, most plumbers bill on completion. For larger jobs, a deposit of 10-30% is standard, with milestone payments for multi-day work and the balance due upon completion.

Red flag: Asking for 100% upfront, pushing a maintenance contract before starting work, or demanding cash-only payment.

Warranty and follow-up questions

A plumber who stands behind their work will put it in writing. Don’t accept verbal guarantees.

For a deeper look at what should be covered after the crew leaves, see our guide to what a good plumber warranty usually covers.

What warranty do you offer on labor and parts?

Industry standard is one to two years on labor. Parts warranties vary by manufacturer — faucets often have lifetime coverage, water heaters carry 6-12 year warranties, fixtures typically have 1-5 years.

Ask: “Can you put the warranty in writing on the estimate? Is the labor warranty from your company or the manufacturer? What’s covered — parts and labor, or just parts?”

Red flag: Vague promises like “we stand behind our work” without specific written terms.

What happens if something goes wrong after the job?

How does the company handle warranty service? Do they prioritize existing customers? How quickly will they respond? “Call us and we’ll be there within 48 hours at no charge” is better than “we’ll take care of it.”

What should I watch for in the first 30 days?

A good plumber will tell you what to monitor after the job — checking for drips at connections, running hot water weekly, or other maintenance. If they don’t offer guidance, ask.

Red flags to watch for

Some signals are worth stopping the conversation right there.

You can’t verify their license. Do not proceed.

They demand full payment upfront. No legitimate plumber does this.

They don’t pull permits. Permit-required work (water heaters, sewer lines, gas lines) must be inspected. A plumber who says “we don’t need permits” or “permits are a money grab” is not someone you want in your walls.

They pressure you to decide immediately. “I can do it today for $800, but tomorrow the price goes up” is a hard-sell tactic. Legitimate plumbers give you time to think and get a second quote.

They can’t provide a written estimate. A handshake and a verbal number is not a contract. Get scope, price, materials, and warranty in writing.

Their online reviews show a clear pattern. One bad review among hundreds is nothing. A pattern of complaints about missed appointments, surprise charges, or unfinished work tells you what to expect.

The questions, summarized

Quick-reference list for when you’re on the phone with a plumber:

1. Are you licensed? Can I have the license number to verify?
2. Are you insured? Can you send me a certificate of insurance?
3. Are you bonded?
4. How much experience do you have with this specific type of job?
5. Who will actually be doing the work?
6. Do you charge a diagnostic or service call fee?
7. Is this flat-rate or time and materials?
8. What’s included in the price? What’s excluded?
9. What’s your payment schedule?
10. What’s your labor warranty, and is it in writing?
11. Will you pull permits if required?
12. How do you handle change orders and unexpected findings?
13. What should I watch for after the work is done?
14. Can you provide references for similar work?

FAQ

How do I verify a plumber’s license?

Search “[your state] plumbing license lookup” and enter the plumber’s license number in the state board’s online tool. The lookup shows whether the license is active, when it expires, and any disciplinary actions or complaints on file. If you can’t find an online tool, call the state licensing board directly.

What’s the difference between licensed, bonded, and insured?

Licensed means the plumber has met state requirements for education, experience, and testing. Insured means they carry general liability (covers property damage) and typically workers’ compensation (covers injuries to their crew). Bonded means they have a surety bond that pays you if the plumber fails to complete the job or violates the contract. You want all three for significant work, but licensing and insurance are the two non-negotiables.

How many quotes should I get before hiring?

For any job over $500, get at least three quotes. This helps you spot outliers — a quote dramatically lower than others may be cutting corners. For jobs under $500, one or two quotes are usually enough if the plumber checks out on licensing and insurance.

Should I hire a plumber who works without a permit?

No. Permits exist for safety — they ensure work is inspected by a qualified building official who verifies code compliance. Unpermitted work can cause problems when you sell your home and may affect your homeowners insurance if there’s a claim related to the plumbing later.

Permit questions matter most on larger jobs, especially water heaters, repipes, and sewer work. If multiple drains are backing up or a cleanout shows waste water, review the main sewer line red flags before approving a quick repair.

Is it okay to hire an unlicensed plumber for small jobs?

It depends on your state’s laws and your risk tolerance. Some states allow unlicensed individuals to perform minor repairs under a certain dollar threshold. The practical risk is that unlicensed workers typically don’t carry insurance, so if something goes wrong, you’re on the hook. For anything involving water lines, gas lines, or work inside walls, hire a licensed plumber.

How do I check a plumber’s insurance coverage?

Ask for a certificate of insurance (COI) directly from the plumber. A legitimate COI shows the insurance company name, policy number, coverage limits, and effective dates. You can call the insurance company to verify the policy is active. Don’t accept a screenshot of an insurance card — those can be faked or expired.

What should I do if a plumber refuses to answer these questions?

Treat it as a clear signal to move on. A professional who is licensed, insured, and proud of their work has no reason to dodge questions. If a plumber seems annoyed or avoids giving straight answers about licensing or insurance, thank them for their time and call the next name on your list.

Bottom line

Questions to ask before hiring a plumber aren’t about being difficult — they’re about protecting your home, your wallet, and your peace of mind. Start with licensing and insurance. Then move to experience, pricing, and warranty. Write down the answers so you can compare across plumbers. And trust your instincts — if a conversation feels off, that’s a good reason to keep looking.

The right plumber will welcome your questions. They know an informed homeowner makes a better customer, and that clear communication before the job starts leads to a better outcome for everyone.