Plumbing Business Guides

Licensing and code come first

Before you advertise, find out who licenses plumbing where you'll work: the state, a city or county, or both. BLS notes that most states require plumbers to be licensed ¹, and that license can decide what you may sell and whether you may pull permits or run the company at all.

Where plumbers are licensed individually, the ladder commonly runs from apprentice to journeyman to master, and the company may need its own contractor license or a licensed master who qualifies it. Titles, hours, exams and what each level may do differ by state, so get your board's answers in writing. Ask, too, whether your license covers gas piping, backflow preventer testing and medical gas, or whether each needs its own credential. Where local rules allow it, backflow testing adds short, schedulable visits and repeat customers.

Code is local too. Each building department enforces a specific edition of a plumbing code, often with local amendments, and that code may be based on the International Plumbing Code (IPC) or the Uniform Plumbing Code (UPC) or written by the state. On a permitted job, the inspector checks your new work against that code, so a "simple swap" can pick up items the old installation never had. Learn which jobs need a permit in each town you serve, starting with water heaters, repipes, sewer lines and gas piping.

How to start a plumbing business lists the questions for your board and building departments, plus insurance, bonds, van stock and backflow testing. When you add people, hiring your first plumber covers apprentice supervision limits, license lookups, registered apprenticeship, pay and day-one safety training. Expect competition for them: BLS reports May 2025 median pay of $63,800 a year for plumbers, pipefitters and steamfitters, and projects 7 percent employment growth from 2025 to 2035 ¹.

Safety: water, sewage, gas and trenches

Plumbing has its own hazards, and one risk that outlasts the visit: water. Plan for both before anyone runs a call alone.

• Water damage. A fitting that lets go overnight can soak floors and ceilings. Leak-test before you close anything up, and ask your insurance agent how leaks found weeks later are covered.
• Sewage. Gloves and eye protection on drain work, and a way to wash up before eating.
• Gas. Leak-test every joint you touch, and train whoever answers the phone to tell a caller who smells gas to follow the gas utility's emergency instructions first.
• Trenches. If you dig sewer laterals, learn OSHA's trenching rules first: trenches 5 feet deep or more need a protective system unless they're entirely in stable rock ². Request utility locates through 811 before you dig.
• Older homes. In homes built before 1978, EPA requires anyone paid to disturb paint to be certified in lead-safe work practices ³, so check whether the rule applies before you cut into painted walls, and leave old pipe insulation that may contain asbestos alone until it has been checked.
• Drinking water. Stock only new parts rated for potable water, and keep salvaged parts out of the van's bins.

How plumbing customers buy

Plumbing is bought two ways, and a shop needs a plan for each.

Before you advertise, decide which nights and weekends you'll cover: a listing that says you're open around the clock is a promise someone must keep at 3 a.m. Then build repeat work: referrals from property managers, real estate agents and home inspectors, and a record of every water heater you see, so you're the first call when it fails. How to get more plumbing customers covers phone triage, your Google Business Profile, Local Services Ads, referral partners and reviews.

Planned work is won on paper. How to write a plumbing estimate covers scope, allowances, exclusions, camera findings and side-by-side repipe options. It also explains when the FTC's Cooling-Off Rule applies to a sale made in the customer's home, and its narrow exception for real emergencies.

Where plumbing money is made and lost

Plumbing margins are won or lost in details the customer rarely sees: billable hours, truck stock, the code items around a water heater and the pipe behind the wall.

• Start from your cost per billable hour. Drive time, supply house runs and callbacks mean you bill fewer hours than you pay for. How to set your labor rate does the math.
• Sell repeatable work from a price book. Flat-rate pricing fits fixture repairs, drain clearing and water heater swaps. Bill open-ended work, like a leak hunt behind finished walls, by the hour with a cap.
• Quote fees before you dispatch. State your service-call fee and after-hours rates up front, and offer a night-time make-safe visit with the permanent repair at regular rates.
• Mark parts up on a sliding scale. Use bigger multiples on cheap parts and smaller ones on water heaters and fixtures customers can price online, then check the result as margin.
• Price water heaters as whole installs. Include what the adopted code and the site require around the tank, such as thermal expansion control, a drain pan, relief valve discharge piping and venting, plus the permit and haul-away.
• Look before you price the unknown. Clearing a drain and repairing it are separate jobs, and a camera inspection comes before any repair price.
• Collect on time. Take payment on service calls before you leave, and bill repipes and remodels in stages tied to inspections.

How to price plumbing jobs builds the price book, the fees and water heater pricing. How to invoice plumbing jobs covers on-site invoices, warranty terms, photos, progress billing and your state's lien notice rules.

The plumbing year

Plumbing demand follows cold and water. Where winters freeze, cold snaps bring frozen and burst pipes that push every other job aside. Spring brings sump pump checks, outdoor faucet repairs and irrigation start-ups. Summer is the time to sell planned projects and hire. Fall is for winterizing and water heater service, and the holidays bring kitchen sink and main line clogs. In warm climates, build the calendar from your own call history instead.

A service agreement puts paid visits into the slow weeks and gives members a reason to call you first. The plumbing seasonal playbook lays out messages, on-call staffing for freezes and thaws, truck stock and cash flow, season by season.