Questions to ask
1. Are you (or is the supervising plumber) a NYC Department of Buildings Licensed Master Plumber, and can I see the license number?
Why it matters: In New York City, plumbing work on piping systems generally must be performed by a DOB Licensed Master Plumber (LMP) or by employees working under that LMP’s direct and continuing supervision. Ask for the Master Plumber license number and the business name tied to it. Verify status through the official NYC DOB licensee search / Public Portal (License Search) on the Department of Buildings site — do not rely on a business-card claim alone. NYC rules also expect the LMP’s business to maintain a New York City place of business that complies with zoning (not a home office), and license numbers should appear on ads, trucks, and business cards as required by the NYC Construction Codes. Also ask for proof of liability insurance and workers’ compensation if they bring helpers — uninsured injury or property damage becomes your problem. “We’re bonded” is not a substitute for verifying an active NYC DOB Master Plumber license and insurance certificates.
2. Will the estimate be written, itemized, and binding — or is it a rough range?
Why it matters: Verbal quotes invite surprise charges, especially when a camera finds collapsed cast-iron drain lines under a brownstone, a riser opens into a neighbor’s line in a walk-up, or co-op board rules force after-hours work and extra protection. An itemized written estimate (labor, parts, trip charge, permit fees if included, disposal, building protection) lets you compare NYC plumbers apples-to-apples. Ask what is excluded, how change orders are priced, and whether the price holds for a defined period. Get the company name, NYC DOB Master Plumber license number, and estimate date on the document.
3. Who will actually do the work — you, an employee under your LMP supervision, or a subcontractor?
Why it matters: Some companies dispatch less experienced techs or subcontractors after a sales visit. Knowing who shows up affects quality, warranty responsibility, and whether the person on-site is covered by the company’s insurance and works under a properly licensed NYC Master Plumber. Ask whether trainees or helpers work unsupervised on your job and who is responsible if a sub’s work fails. For larger jobs (repipe, house-connection / sewer lateral work, remodel rough-in, gas piping), confirm a Licensed Master Plumber remains accountable for the finished work.
4. What is your warranty on parts and labor, and what voids it?
Why it matters: A clear warranty (duration, what it covers, how to claim) signals confidence. Ask whether manufacturer warranties transfer, whether DIY follow-up work voids their labor warranty, and who you call if a valve or water heater fails six months later. Get warranty terms in writing with the final invoice — especially important after NYC winters stress aging supply lines and freeze-prone stacks, in older brownstones and walk-ups where one repair may reveal nearby failures, and where building staff or prior DIY work may have altered shutoffs and valves.
5. Do you pull required DOB permits for this work through DOB NOW: Build, and is that included in the price?
Why it matters: Installing, relocating, or altering plumbing systems in NYC generally requires DOB plumbing permits and inspection. Filings commonly run through DOB NOW: Build; larger or more complex work may also need drawings prepared by a New York State Professional Engineer (PE) or Registered Architect (RA). Pros who skip permits “to save you money” leave you exposed if something fails, if insurance questions arise, or when you sell or refinance. Ask who submits each permit, who pays DOB fees, whether inspection scheduling is included, and whether your job needs PE/RA drawings. Separate from DOB: if you live in a co-op or condo, ask how they handle building management or board approval packages — that is not the same as a DOB permit and can delay start even when the city paperwork is ready.
6. How do you price emergency or after-hours calls?
Why it matters: Emergency rates can be substantially higher than daytime rates — and NYC winters make freeze bursts, failed boilers/water heaters, and after-hours sewer backups real emergencies, while a burst supply line or no-hot-water call is urgent any season. Get the after-hours multiplier, minimum call-out fee, diagnosis fee, and whether that fee applies to the repair before you authorize a night visit. Ask how they prioritize true emergencies (active flooding, no water, gas smell — call the utility/emergency services for gas) versus next-morning jobs, and whether building staff access or after-hours elevator rules affect timing. Clear pricing up front beats arguing over a bill at 2 a.m. after a frozen riser or cellar backup.
7. Given NYC housing stock, how will you assess older brownstones, walk-ups, co-ops/condos, cast iron/galvanized laterals, and high-rise stacks before quoting a full fix?
Why it matters: Pre-war brownstones and townhouses (Park Slope, Harlem, parts of Brooklyn and Manhattan), walk-ups, and older stock in Astoria, Riverdale, and similar neighborhoods often still have cast iron or galvanized drain and supply laterals, basement or cellar plumbing, and shared stacks. Co-ops and condos add board rules, building engineer preferences, and limited work hours. High-rises introduce stack issues, pressure zones, and access through common areas. A low bid that only patches the visible symptom can miss the larger condition. Ask whether they will check accessible shutoffs, pressure, water heater or boiler-related plumbing, cleanouts, and nearby piping; whether they recommend section repair vs repipe or house-connection options; and how they price exploratory work if walls, floors, or cellar slabs must open. Require a stop-and-call process before extra work begins. Stay general on lead service lines: ask whether they will discuss private-side service-line condition and point you to NYC DEP lead service line information rather than inventing claims about your address.
8. If this job involves gas piping or appliances, what gas-related credentials and permits apply — and how do you handle them?
Why it matters: Gas work in NYC is tightly regulated. Ask carefully whether the Licensed Master Plumber (or supervised crew) holds the gas-related qualifications needed for your scope — for example Gas Work Qualification / related credentials as applicable — and which DOB filings cover the gas portion. Do not accept vague “we do gas” answers; ask what they will file, who inspects, and what you must shut off or vacate during the work. For any gas smell or suspected leak, treat it as an emergency with the utility and emergency services first — not a shopping comparison. Keep claims modest: confirm the exact credential names and permit path for your job with the plumber and DOB rather than relying on marketing language.
9. How do you handle cleanup, floor protection, and any NYC DEP water/sewer house-connection coordination at a high level?
Why it matters: Plumbing jobs track water and debris through finished apartments and brownstones — and NYC’s hardwood floors, tile baths, and shared hallways make good floor protection and dust control pay off. Pros who bring drop cloths, shoe covers, and a cleanup plan reduce secondary damage and neighbor complaints. If the job involves water or sewer house connections (new connection, repair/relay, or plug), NYC Department of Environmental Protection (DEP) rules apply: a Licensed Master Plumber typically files many DEP sewer connection permits, while House or Site Connection Proposals / sewer certifications are generally prepared by a PE or RA when required. Ask what they handle versus what needs a design professional or DEP review, and stay general — verify utility-side requirements with DEP (and DOB for related house-connection inspections) rather than relying on marketing claims.
10. What brand or grade of fixtures and parts do you typically install, and can I choose?
Why it matters: Cheap valves and supply lines fail early — faster still under NYC water conditions, hard use in rentals, or freeze-thaw stress. Ask about options (builder-grade vs mid-tier), whether they will install customer-supplied fixtures, and how that affects warranty. For water heaters, ask about capacity, fuel type (including tankless where relevant and code-allowed), anode/flush recommendations, expansion tanks or recirculation if in scope, and whether closet or basement placement needs pan, drain, and ventilation considerations in tight NYC layouts. Get model numbers on the written estimate when equipment is part of the job. In co-ops/condos, ask whether building management has preferred brands or approval rules for fixtures that affect common stacks.
11. Can you provide recent NYC-area references for similar jobs?
Why it matters: A water heater swap in a Queens condo is different from a cast-iron drain repair under a Brooklyn brownstone or a gas range reconnect in a Manhattan walk-up. Ask for recent local references for comparable work across the boroughs you care about, how long they have served NYC, and whether you can see photos of finished jobs (with board/privacy constraints respected). References beat star ratings alone when you need punctuality, DOB permit follow-through, DEP coordination when needed, and a fix that lasted through a New York winter.
Red flags
- Cash-only demand, or pressure to pay the full amount before work starts.
- No written estimate, or vague “it depends” pricing with no cap or change-order process.
- Cannot or will not provide a NYC DOB Licensed Master Plumber license number you can verify on the official DOB license search / Public Portal, or an insurance certificate.
- Discourages DOB permits “to save you money” on work that typically needs inspection — or shrugs off co-op/condo board approval as optional.
- Dramatically lower bid with no explanation of scope, parts grade, or permit exclusions.
- Arrives unmarked, or wants you to leave the apartment while they work with no identification.
- Pushes a full repipe, house-connection replacement, or water heater swap without diagnosing the actual failure or showing you options.
Next-step checklist
- Verify the Licensed Master Plumber’s NYC DOB license via the official DOB licensee search / Public Portal before hiring.
- Get at least two written, itemized estimates for the same scope (parts, labor, permits, exclusions).
- Confirm liability insurance (ask for a certificate with your address if the job is large) and workers’ comp if helpers are on-site.
- Clarify DOB NOW: Build permit responsibility and whether PE/RA drawings are needed; separately confirm co-op/condo board or building-management approval if you live in one.
- Agree in writing on warranty length, payment schedule, and the stop-and-call change-order process.
- Locate and test your main water shutoff and cleanout if accessible (apartment riser shutoff, cellar main, or meter area as applicable); photograph the problem area before work begins.
- Keep receipts, DOB permit numbers, DEP references if any, and the final invoice for future buyers, boards, or warranty claims.