Step one: verify the license
California licenses plumbing contractors through the Contractors State License Board. The board offers an online license check where you can enter a contractor's name or license number and see whether the license is active and which classification it holds. Do this before you let anyone into your home.
Ask the company for its business name and license number, and compare them with the record. If a business cannot give you a license number, or the record does not match, walk away.
Step two: ask what the quote covers
| Question | A good answer | A warning sign |
|---|---|---|
| Is the price clear before work starts? | Yes, in writing for defined jobs | Vague, or only a per-hour rate with no cap or scope |
| What is included? | Parts, labor, permit, haul-away | Unclear, with extras added later |
| What if you find something else? | Stop, show me, revise the price | Proceeds without asking |
| Do you pull permits when needed? | Yes, and explain which | Suggests skipping the permit |
| Is after-hours priced differently? | Yes, stated up front | Surprises on the invoice |
Prices are built from access, diagnosis, parts, timing and permits, so ask each plumber how their quote treats all five.
Step three: understand permits and who pulls them
Many jobs need a permit, and the contractor should explain which. In the Central San service area, exterior sewer work needs the district's permit before any digging, and the contractor must be registered with the district. For a water heater, ask the building division of your city which permit applies.
Red flags
- A demand for a large cash deposit before any work starts.
- A refusal to give a license number.
- Pressure to decide immediately.
- A price that changes by phone and in person.
- No explanation of what is wrong, only what to buy.
- Suggesting a full replacement before looking.
What a clear explanation sounds like
Names the cause
Not just replace the pipe, but the pipe is corroded at this joint.
Shows evidence
A camera clip, a photo, a gauge reading.
Offers options
Repair, replace, or wait, with trade-offs for each.
States limits
What the plumber cannot know until the wall is open.
Emergencies: what to ask on the phone
In an emergency you may not have time for a full vetting. You still have time for three questions: are you licensed, can you give me a clear price before work starts, and when can someone arrive. Our line is answered 24/7, and we will tell you the answers before we send a crew. See our burst pipe repair page and our drain cleaning page for what the first minutes look like.
After the job
Keep the invoice, the permit and any warranty paperwork. Photograph the finished work. If the work involved a sewer lateral or water heater, the permit record helps at resale.
A short script for the first phone call
- Are you licensed, and what is the license number I can check?
- Can you give me a clear price before work starts?
- What is the earliest visit you can offer, and what does it depend on?
- Will you pull the permit if the job needs one?
- If you find something else, will you stop and tell me before continuing?
Five questions take two minutes and tell you most of what you need. A plumber who answers them directly is probably one who will explain the work later too. If you are mid-emergency, ask the first two and the last one, and sort out the rest when the water is off.
Standards a good plumber can name
Ask which code the job follows. The right answer is the California Plumbing Code, which is based on the Uniform Plumbing Code (UPC), plus any local amendments and the sanitary district's specifications for sewer work. A plumber who can name them is a plumber who works to them.
Pleasant Hill: local agencies to know
Central San states that property owners are responsible for their private sewer laterals and that contractors must be registered with the district to pull its permits. That is a useful question for any plumber who proposes sewer work.
For water heaters, the City of Martinez publishes a handout of California Plumbing Code items inspectors check, including seismic straps and a relief valve drain. It is a useful checklist even if you live elsewhere, but ask the Pleasant Hill building division for local rules.
Neighbors may read the Martinez page or the Concord page for local agency notes.
Local questions
Use the Contractors State License Board online license check and match the business name and license number.
For non-emergency work, compare at least two and compare the scope, not just the total.
Large cash deposits before work starts are a red flag. Ask what the company's policy is.
A good plumber stops, shows you and revises the price before continuing.
The contractor usually does, and should tell you which permit applies.
Still have a question about your situation? Call (855) 575-2890 any hour and describe what you are seeing.