Plumbing, electrical, and roofing contractor data quirks

HVAC gets most of the attention in home services data because it's the biggest category by revenue. The other three core trades (plumbing, electrical, and roofing) each have their own data quirks that trip up first-time buyers. We've built lists in all three and the gotchas are different for each.

Plumbing: the master license problem

Plumbing licensing is the most consistent across states. Almost every state requires a license, and the typical structure is a Master Plumber (can run a business and pull permits) plus Journeyman and Apprentice tiers (work under a master).

The data quirk: many plumbing businesses operate under a single master plumber's license, but the business itself isn't named on the license record. The license lists the master plumber's name. You have to join license records to business filings to get the company name, address, and contact info.

In Texas, for example, the Texas State Board of Plumbing Examiners publishes roughly 36,000 active Responsible Master Plumber (RMP) records. Joining these to active business filings via Texas Comptroller data yields about 8,200 actively-trading plumbing companies. The 4-to-1 ratio is typical: most master plumbers work for someone else's company, and the company-to-license join is where data quality lives or dies.

Niche plumbing subtypes (drain cleaning, water heater installation, sewer line, backflow prevention) are typically separate certifications, not separate licenses. A licensed plumber can do all of it. If you're segmenting by subtype, you need business listings and service-area data, not license categories.

Electrical: where unions and IBEW shape coverage

Electrical contractor licensing is similar to plumbing but skews more toward commercial work in states with strong IBEW (International Brotherhood of Electrical Workers) presence. About 65 percent of electrical contractors do mostly commercial. Residential service electricians are a smaller subset and harder to isolate in license data.

The data quirk: license classifications often combine residential and commercial under a single Class A or Master Electrician license. To segment for residential-focused shops, you need ancillary signals (NABCEP solar certifications, EV charger installer registrations with specific OEMs, residential-coded business listings).

The booming subsegment is EV charger installation. Tesla's certified installer network, ChargePoint's network, and ChargerHelp's data all publish installer locations. These are useful overlays on a base electrical contractor list.

For solar specifically, NABCEP (North American Board of Certified Energy Practitioners) publishes about 5,000 certified PV installers. This is a tiny fraction of the electrical universe but the right list if you sell into the solar installer segment specifically.

Generator installation (Generac, Kohler, Briggs & Stratton) operates a similar OEM-dealer network model to HVAC. Generac's PowerPro program lists roughly 8,000 dealers nationally. Useful for anyone selling adjacent products.

Roofing: the permit data goldmine

Roofing is the most permit-driven of the four core trades. Almost every roof replacement requires a permit, and most jurisdictions list the roofing contractor on the permit. This makes permit data (Shovels.ai, BuildZoom, and direct municipal pulls) the strongest signal for active roofing contractors.

The data quirk: roofing licensing varies more by state than any other trade. Florida, Texas, California, and Arizona require state roofing licenses. Many northern states (Michigan, Ohio, Pennsylvania) defer to municipal or county licensing. A handful of states have no roofing license requirement at all.

In hail-belt states (Colorado, Texas, Oklahoma, Kansas, Missouri), roofing also has a storm-chaser dynamic. After a major hail event, hundreds of out-of-state crews pour in and pull permits under temporary registrations. These show up in permit data as roofing contractors but disappear six months later. Buyer beware on permit-only roofing lists in hail markets.

Insurance restoration is a related but distinct segment. Roofers who do insurance work tend to belong to specific networks (RCAT in Texas, NRCA nationally, RCS Roof Connect). Membership lists are useful overlays.

For storm-driven outreach, the combination of license data (to filter out fly-by-night operators) plus permit data (to confirm recent activity) plus insurance network membership (to confirm restoration focus) is the right stack.

Landscaping: the unlicensed elephant

We get asked about landscaping enough to address it here. Landscaping is the most under-licensed of the home services trades. Only a handful of states (California, Florida, Texas, North Carolina, Tennessee) license landscape contractors. Most states defer to municipal or none at all.

For landscaping prospect lists, license data is a small subset of the universe. Business filings, Yelp, Google Business Profile, and irrigation contractor licensing (which is required in more states than landscaping) cover the rest.

Irrigation contractor licensing (Texas TCEQ, Florida DBPR, etc.) is the most reliable signal for landscaping operators who do residential service work, since irrigation is a common upsell. About 14,000 active irrigation contractor licenses exist nationally.

How we handle each trade

Our methodology adjusts per trade. For plumbing, we lead with master plumber license records and join to active business filings. For electrical, we layer license records with OEM dealer networks (Generac, Tesla, NABCEP). For roofing, we combine license data with permit history and insurance network membership.

The result is a list that reflects each trade's reality rather than a one-size-fits-all join. See custom list building for how we scope projects.

The cross-trade overlap

A non-trivial percentage of contractors hold licenses in multiple trades. About 12 percent of plumbing license holders also hold an HVAC license. About 8 percent of electrical contractors also hold a low-voltage or solar license. For dedup and segmentation, this matters: a license-driven dataset will double-count multi-trade operators unless you reconcile at the business level.

We reconcile via EIN and business address. Two licenses, same EIN, same address = one operator with multiple licenses. License verification covers this if you have an existing list that's been double-counted.

Trade-specific seasonality

Each trade has its own outbound calendar. Plumbing service work peaks in winter (frozen pipes, water heater failures, holiday cooking emergencies). Plumbing install work peaks in Q2 and Q3 with new construction season. The shop owner is hardest to reach in December and January if they have a service-focused business.

Electrical service peaks around storm season in storm-belt states. Generator install spikes after major outage events (the Texas freeze in February 2021 drove a 4x spike in residential standby generator demand that took 18 months to absorb). Solar installation cycles with state and utility rebate windows; pay attention to which state programs are in active enrollment when you build a solar-electrical list.

Roofing is the most weather-driven of the four. Spring through early fall is install season nationally. Hail events drive 6-to-12-month spikes in restoration work. The best outbound window for selling into established roofing operators is November through February when crews slow and owners catch up on operations.

The commercial-vs-residential cut

For each of these three trades, the commercial-vs-residential cut materially affects the buyer profile. Commercial plumbing operators tend to be larger, more bid-driven, and have longer sales cycles. Residential service plumbing operators are smaller, more relationship-driven, and convert faster.

License data alone rarely identifies commercial-vs-residential split. The cleanest signals come from business listings (residential operators list 24/7 emergency service; commercial operators list bid services and project management), permit history (commercial permits are larger and tagged differently), and employee profiles on LinkedIn (estimator and PM titles vs. service tech titles).

For vendors targeting commercial plumbing or electrical operators specifically, layer in NIBS (National Institute of Building Sciences) member lists, MCAA (Mechanical Contractors Association of America), and NECA (National Electrical Contractors Association) chapter rosters. These are smaller universes (typically 8,000 to 15,000 commercial-focused operators per trade nationally) and high quality.

Insurance and bonding requirements

Roofing is the most insurance-driven trade because hail and storm restoration work runs through insurance claims. Roofers who work the insurance restoration channel typically carry larger bonds, hold specific insurance restoration certifications, and belong to networks like RCAT, RCS Roof Connect, or NSI (National Storm Industries).

For insurance carriers, third-party administrators, and adjacent vendors targeting the restoration channel specifically, the insurance-restoration-active subset is the right segment. State license data plus network membership plus recent permit volume isolates it cleanly.

For plumbing and electrical, bond size on the state license record is a useful proxy for company size. Larger bonds correlate with larger commercial-focused operators. The bond field is published in most state license records.

Picking the right starter trade for outbound

If you're testing contractor outbound for the first time and choosing between trades, the test-trade decision matters. Plumbing has the cleanest license data nationally and the most predictable buying calendar; it's a good starter trade for emergency-service-adjacent products.

Electrical works well for energy-transition products (EV chargers, solar, battery storage) where the operator base is already segmented by adjacent certifications. The smaller universe makes targeted outreach manageable.

Roofing is the best test trade for storm-restoration products and insurance-adjacent services. Permit data overlays make recent-activity signals strong. Avoid roofing as a starter trade if you're not prepared for the storm-chaser noise in license data.

For most vendors with cross-trade products, starting with plumbing and expanding from there is the simplest path.