Questions to ask
1. Are you licensed with the California Contractors State License Board (CSLB), and can I see your license number?
Why it matters: In California, most plumbing contractors must hold an active CSLB license (commonly a C-36 Plumbing Contractor classification for plumbing work, or another classification that legally covers the scope). Ask for the exact license number and verify status, classification, and any disciplinary history on the CSLB website before you authorize work. 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 the license and insurance certificate.
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 walls open and older galvanized or mixed-metal lines appear. An itemized written estimate (labor, parts, trip charge, permit fees if included, disposal) lets you compare LA 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, CSLB number, and estimate date on the document.
3. Who will actually do the work — you, an employee, 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. Ask whether apprentices work unsupervised on your job and who is responsible if a sub’s work fails. For larger jobs (repipe, sewer, remodel rough-in), confirm the licensed contractor 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 in LA’s older housing stock where related piping failures can appear after the original repair.
5. Do you pull required permits for this work, and is that included in the price?
Why it matters: Water heater replacements, gas line work, sewer alterations, and many remodel plumbing scopes often require permits and inspection through the City of Los Angeles (or your local AHJ if you are in an incorporated city or county area outside City of LA limits). Pros who skip permits “to save you money” leave you exposed if something fails, if insurance questions arise, or when you sell the home. Ask who submits the permit, who pays AHJ fees, and whether inspection scheduling is included. Confirm your exact jurisdiction — rules differ across City of LA, other LA County cities, and unincorporated areas.
6. How do you price emergency or after-hours calls?
Why it matters: Emergency rates can be substantially higher than daytime rates. 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. Clear pricing up front beats arguing over a bill at 2 a.m.
7. Given older LA housing stock, how will you assess galvanized lines, mixed metals, and shutoff access before quoting a full fix?
Why it matters: Many Los Angeles neighborhoods still have homes with original or aging galvanized steel, polybutylene from later decades, or mixed copper and galvanized transitions that corrode. A low bid that only patches the visible leak can miss the larger condition. Ask whether they will inspect accessible shutoffs, pressure, and nearby piping; whether they recommend section repair vs repipe; and how they price exploratory work if walls or slabs must open. Require a stop-and-call process before extra work begins.
8. Do you install or service earthquake shutoff valves and main water shutoffs, and will you show me how to use them?
Why it matters: Southern California homeowners often want a working main shutoff — and sometimes a seismic gas shutoff valve (gas work may involve different licensing and utility rules). Ask whether they will locate and test your main water shutoff, replace a seized valve, and walk you through operation before they leave. For gas-related devices, confirm the work is within their license and that required permits/inspections are handled. Knowing how to stop water quickly matters as much as the repair itself.
9. How do you handle cleanup, floor protection, and any utility coordination (for example LADWP or your water provider) at a high level?
Why it matters: Plumbing jobs track water and debris through finished homes. Pros who bring drop cloths, shoe covers, and a cleanup plan reduce secondary damage. If the job involves meter-side issues, service interruptions, or questions about your water provider’s rules, ask what they handle versus what you must arrange with LADWP or your local water utility. Stay general: the plumber should explain their process; verify any utility-side requirements with the utility itself 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. 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, seismic strapping where required, and whether expansion tanks or recirculation are in scope. Get model numbers on the written estimate when equipment is part of the job.
11. Can you provide recent Los Angeles–area references for similar jobs?
Why it matters: A water heater swap in a canyon home is different from a slab leak in the Valley or a whole-house repipe in a 1920s bungalow. Ask for recent local references for comparable work, how long they have served the LA area, and whether you can see photos of finished jobs. References beat star ratings alone when you need punctuality, permit follow-through, and a fix that lasted.
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 CSLB license number you can verify, or insurance certificate.
- Discourages permits “to save you money” on work that typically needs inspection.
- Dramatically lower bid with no explanation of scope, parts grade, or permit exclusions.
- Arrives unmarked, or wants you to leave the house while they work with no identification.
- Pushes a full repipe or water heater swap without diagnosing the actual failure or showing you options.
Next-step checklist
- Verify the contractor’s CSLB license status and classification on the CSLB website 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 your AHJ (City of LA vs other city/county) and whether permits/inspections are included.
- Agree in writing on warranty length, payment schedule, and the stop-and-call change-order process.
- Locate and test your main water shutoff; photograph the problem area before work begins.
- Keep receipts, permit numbers, and the final invoice for future buyers or warranty claims.