Half the trucks in this metro say heating, air, and plumbing now. Some of that is the roll-ups bundling trades under a local name they bought. Some of it is independents who added a trade to flatten the year. Either way, your customers are starting to expect one number to call, and somewhere in the shoulder season you have wondered whether you should be one of them.
Here is the short version. In Maryland this is a hiring or acquisition decision, not a training decision, because nobody is training his way onto a plumbing license in under six years. Insurance moves. And the shops that lose money on it are almost always the ones that added the trade everywhere except online.
There is also a route most owners have never heard of that runs through the license you already hold, and it is probably the more interesting answer. It is in the fourth section.
Nothing here tells you whether to expand. Staying a pure HVAC shop is a legitimate strategy, and for plenty of companies the right growth is depth in heating and cooling rather than breadth across trades.
Why this comes up every shoulder season
Three drivers, and all three are real.
The first is the seasonal swing. September and April are quiet, payroll is not, and a second trade looks like a way to fill a valley. Our article on surviving the slow season covers the cheaper ways to do that, and this is the expensive one.
The second is competitive. When a private-equity-backed group buys three shops in your county and puts plumbing on all of them, it is not just adding a service. It is teaching homeowners that a heating company should also handle the water heater, and that expectation lands on you whether or not you asked for it.
The third is your own customers. Older homeowners in particular like having one company they trust rather than three they have to vet. That preference is genuine and it is worth something.
None of which tells you the answer. It tells you why the question keeps coming back.
What Maryland actually requires
Licensing rules change, each board sets its own requirements, and counties layer their own registrations and permits on top, so confirm everything here with the boards directly before you commit to anything. We are not attorneys and this is not legal advice. Everything below is drawn from the Maryland Department of Labor and Maryland OneStop and was checked in August 2026.
Start with the structure. HVACR, plumbing, and electrical are three separate boards under the Department of Labor’s Division of Occupational and Professional Licensing. They do not talk to each other and holding one license gets you nothing on another ladder.
The plumbing ladder. To sit for the journey plumber and gas fitter exam, the Board requires that you have held an apprentice license for at least four years, completed 7,500 hours of training under a licensed master plumber, completed 32 hours of backflow prevention device testing training, and passed a written exam at 75%. Master requires holding that journey license for at least two more years, another 3,750 hours, and a second exam.
Read that again as an owner rather than as a tradesman. Six years minimum, more than 11,000 supervised hours, two exams. You are not doing that, and neither is your best installer on a timeline that helps your business. This is a hiring decision or an acquisition decision. There is no third door.
The gas fitting door, which is the part nobody tells you. The Board’s own requirements page lists a route to a master natural gas fitter license for someone who already holds an HVACR master or master restricted license, has at least two years of gas fitting experience as a journey gas fitter under an approved master gas fitter, master plumber, or HVACR master, and passes an examination at 70%.
That is a materially different proposition. It runs through the license you already hold, it covers work adjacent to what your crew already does, and a gas fitter license authorizes natural gas services rather than the full plumbing scope. For a lot of Maryland shops the honest answer to “should we add plumbing” is no, and the better question is what the HVACR license you already have can be extended to cover.
Electrical, which works differently and catches people out. Since July 2021 the state issues apprentice, journeyperson, and master electrician licenses, and local authority to license was repealed. Master requires roughly seven years of supervised experience, with up to three years creditable for formal training, plus an exam. Journeyperson requires four.
Here is the catch. The state license is necessary and it is not sufficient. The Board’s own FAQ says plainly that local jurisdictions may still require registration in order to provide electrical services and pull permits there. Baltimore County, for one, requires master general electricians to register with the county, and as of January 2026 requires 10 hours of continuing education every two years tied to that registration. A shop working across Baltimore County, Baltimore City, Howard, Anne Arundel, and Montgomery is looking at one state license and a stack of county registrations, each with its own renewal.
Insurance minimums. Both the plumbing and electrical sides require proof of $300,000 in general liability and $100,000 in property damage coverage, with the Board named as certificate holder. That is the floor to hold the license, not what your broker will actually recommend you carry.
Reciprocity, and a wrinkle worth knowing. The Board of Plumbing reciprocates with Delaware for the master plumber and gas fitter license only. Separately, individuals holding a current journey or master gas fitter license from Baltimore County or WSSC may obtain the equivalent state natural gas fitter license. WSSC covers Montgomery and Prince George’s counties, so if your expansion runs toward the DC side, that route is worth asking about specifically.
Across the line. The District licenses through DLCP and Virginia through DPOR, and neither is Maryland. If your trucks cross a state line regularly, the licensing map is three maps, and the answer to every question in this section changes at the county line.
One thing to ask about directly. Water heaters sit right on the boundary, because a gas water heater is gas utilization equipment and also a piece of plumbing. Owners assume it is fair game because it looks like equipment. Do not assume. Ask the Board where that line falls for the specific license you hold or plan to hold, and get the answer in writing before a truck goes out.
What it costs after the license
The license is the part everybody researches. The rest is the part that decides whether it works.
- Insurance, which is bigger than the minimums. Contractor forums consistently report that adding a second licensed trade roughly doubles general liability premiums. That is forum discussion, not published data, and we could not find a broker source that confirms the multiple. Treat it as the shape of the answer and get a real quote before you commit, because it is the single number most likely to change the math.
- The hire. A master plumber commands a master plumber’s pay, and you are bidding for him against plumbing companies who need him more than you do.
- Truck, tools, and stock. A different trade means a different parts inventory, and inventory you carry badly is inventory that sends techs to the supply house mid-job.
- A permit workflow your office has never run. Different inspections, different jurisdictions, different lead times. Your dispatcher learns this on live jobs.
- Callback exposure of a different kind. An HVAC mistake makes a house uncomfortable. A plumbing mistake makes a house wet, and the claim that follows is a different size.
None of that is an argument against expanding. It is an argument for pricing the expansion honestly before the truck lettering gets ordered.
The person whose name is on the license
The forums call this the single point of failure and they undersell it, because in Maryland it is structural rather than just inconvenient.
Plumbing work at a company runs through a designated master on record, and that person carries the regulatory responsibility for it. Which means if he leaves, you do not simply lose an employee and slow down. The authority under which the company performs that work walks out with him, and it walks out mid-job, mid-permit, mid-inspection. Confirm the exact mechanics with the Board for your entity type, because this is the detail that turns a staffing problem into a stop-work problem.
Shops handle it four ways. Get a second licensed person on staff, which doubles the cost of the thing you were trying to test cheaply. Write a non-solicit where it is enforceable. Give him equity or a profit share so leaving costs him something. Or accept the risk with your eyes open, which is a legitimate choice as long as it is a choice rather than an oversight.
Three ways in: hire, buy, or partner
Hire a master and build around him. Cheapest to start, slowest to produce, and it concentrates every risk in the previous section into one person. It also means you are building a plumbing operation from zero: no customer list, no permit history, no crew.
Buy a small plumbing company. This buys the license, the crew, the customer list, and the permit workflow in one transaction, and it is how most successful additions actually happen. It is also a real acquisition with real diligence, and the same math you would face as a seller runs in reverse. Our article on what an HVAC business is worth covers the multiples, the modifiers, and why the headline number is not the check, all of which applies to you as the buyer.
Partner and refer. The option nobody writes about, because nobody makes money selling it to you.
A formal referral relationship with a plumber you actually trust captures most of what the customer wanted. They call one number, they get a real answer, and somebody they trust vouches for who shows up. You get none of the licensing exposure, none of the insurance jump, and none of the hiring risk. The trade is that you do not capture the revenue, and the relationship is only as good as the plumber.
For a shop under about fifteen people this is frequently the right answer, and it is worth trying for a year before you commit to anything harder to undo.
What to add instead, if the answer is no
Depth is a growth strategy too, and most of these need no new license at all.
Duct replacement, which is labor-heavy and nobody wants scheduled in July, so it lives naturally in the valley. Indoor air quality work: filtration, humidifiers, dehumidifiers, UV. Thermostat and zoning upgrades. One or two light commercial jobs an off season to keep crews busy, which many of your residential customers can hand you because they own or manage a business.
And gas fitting, if the pathway above fits your license and your people. It is the only item on this list that meaningfully widens what you are legally allowed to do, and it is the one an HVAC shop is closest to already.
The part everybody skips: making the new trade findable
This is what we sell, so read it accordingly. It is also the section with the most money in it.
Adding a service is like adding a zone. The equipment can be perfect and if there is no duct to the room, the room stays the same temperature. The license is the equipment. Everything below is the ductwork.
Search engines and AI assistants build a picture of what your business is from every source at once: your website, your Google Business Profile categories, Bing Places, Apple Maps, the directories, the manufacturer listings, and the text of your reviews. When those sources disagree, nothing resolves the conflict in your favor. The machine reads a company that is mostly described as an HVAC contractor and describes it as an HVAC contractor. Verified August 2026. AI answers shift, so check it yourself.
Which is how a shop ends up with a licensed plumber on payroll, plumbing on the trucks, and no plumbing calls. The trade got added in the physical world and nowhere else.
Adding it properly means adding it everywhere at once.
- Real service pages, not a line on the homepage. One page per service you actually want calls for. A homeowner searching for a water heater replacement is not going to find it in a bullet on your about page, and neither is anything reading the site.
- Google Business Profile categories, chosen deliberately. You can add categories, but the primary category still does most of the work, and changing it is a real decision rather than a checkbox. Think about which searches you most need to appear for before you touch it.
- Every other listing updated to match. Bing Places, Apple Maps, Yelp, Nextdoor, the manufacturer dealer pages, the directories. Bing in particular matters more than owners expect, because it feeds answer engines.
- Name, address, and phone identical across all of it. NAP consistency is what lets all those listings count as one business instead of several half-described ones.
- A decision about the company name itself. Going from Smith Heating and Air to Smith Home Services is a bigger move than it looks. A name change resets a great deal of accumulated signal, and it is worth doing deliberately or not at all.
- A plan for the first ten reviews that say the word. Review text is what tells an assistant you actually do the work. Four hundred reviews about furnaces and none about drains describes an HVAC company no matter what the trucks say.
- Structured data that reflects the added service. It makes the relationship readable to machines. It is not a ranking lever and nobody should sell it to you as one.
Being honest about what this does: none of it guarantees the calls come. Plenty of things decide that, and most of them are outside anybody’s control. What it does is make the work findable. Skip it and the work is not findable at all, which is a different and much worse problem, and it is the one we watch shops walk into. Our local search page covers how those signals fit together.
Budget a year for this part. Not because the work takes a year, but because search engines take months to trust a changed picture of a business, and reviews mentioning the new trade only accumulate as fast as you do the jobs.
A ten-minute decision checklist
Answer these honestly and the decision usually makes itself.
- Do you have enough volume in your existing customer base to keep a second trade busy, or are you counting on new customers to justify the hire?
- Can you carry that person’s full loaded cost through a slow quarter with no revenue from him?
- Who is the second licensed person, and what happens the week the first one gives notice?
- What did your broker actually quote for the premium, in writing?
- Will you commit to the online work in the previous section, all of it, in the first ninety days?
- Would a referral partnership get your customers most of what they actually wanted?
- Have you asked the Board whether the gas fitting route fits your license, before deciding this is a plumbing question at all?
If you cannot answer the second and third ones, the honest move is another year of referrals while you build the volume that makes the rest of it obvious.
Frequently asked questions
Can an HVAC company do plumbing in Maryland?
Not on an HVACR license. Plumbing is licensed by a separate board, and the company needs a licensed master plumber on record to perform plumbing work. Your HVACR license does not extend to it. Confirm the entity requirements with the Board of Plumbing directly.
Do I need a separate license to add plumbing?
Yes. HVACR, plumbing, and electrical are three separate boards under the Maryland Department of Labor, and holding one earns you nothing on the others. Electrical adds a second layer, since many counties require local registration on top of the state license.
How much does it cost to add a trade?
Far more than the license fee. Budget a master’s salary, a general liability premium that contractors report roughly doubling, truck and inventory for a different trade, a permit workflow your office has to learn, and a year of visibility work before the phone reflects any of it.
Should I change my company name if I add plumbing?
Only deliberately. A name change resets accumulated recognition, reviews tied to the old name, and every listing you have built. Many shops keep the name and add real service pages instead, which achieves most of the goal without the reset.
Can HVAC technicians do gas fitting in Maryland?
There is a route. The Board lists a master natural gas fitter path for holders of an HVACR master or master restricted license with at least two years of gas fitting experience as a journey gas fitter under an approved master, plus an exam. Verify the current requirements with the Board.
Is it better to hire a plumber or partner with one?
Depends on volume. Below roughly fifteen people, a referral partnership usually delivers most of the customer benefit with none of the licensing, insurance, or hiring exposure. Hiring makes sense when your existing base already generates enough plumbing work to keep someone busy.
Ask the Board before you order the truck lettering
Two phone calls settle most of this. One to the Board of Plumbing to ask whether the gas fitting route fits the license you already hold and where the water heater line falls. One to your insurance broker for a real number on the premium. Neither costs anything and together they answer more than any article can.
And if you do go ahead, treat the online side as part of the project rather than something to sort out later. The license makes the work legal. The rest of it makes the work findable, and a trade nobody can find is the most expensive kind of growth there is.
If you want to see what your company currently looks like to a search engine, that is what the free visibility audit is for: your rankings in every town you serve, your profile against the competitor winning your market, whether your listings agree with each other, and whether AI tools name you or them when a homeowner asks who to call. One page, two business days, yours either way. We work with one HVAC company per service area, so it also tells you whether your towns are still open. Here is how the rest works. Worth a look?