NAICS Code for Plumbing Contractors (238220)
The NAICS code for plumbing contractors is most commonly 238220. NAICS 238220 – Plumbing, Heating, and Air-Conditioning Contractors includes establishments primarily engaged in installing and servicing plumbing systems, HVAC systems, hydronic heating, and related building equipment.
The correct classification depends on the primary activity: plumbing-only service, HVAC installation/service, mechanical contracting, or heavy civil water/sewer line work.
How to choose the correct NAICS code for a plumbing contractor
Quick rule: match the NAICS code to the business’s primary economic activity (the activity that drives the majority of output).
- Plumbing installation/repair in buildings: typically 238220.
- HVAC installation/service (building systems): typically 238220.
- Mechanical contractor doing integrated building equipment installs: often 238220.
- Underground municipal water/sewer line construction: typically 237110.
- Septic system service/pumping: often falls under waste-related services (commonly 562991).
Tip: confirm the definition and included/excluded activities on the destination NAICS page before finalizing a code.
⚠️ Common mistake: using 238220 for municipal water/sewer pipeline construction.
If the primary activity is trenching and installing water/sewer mains, pumping stations, or related civil structures, the correct code is usually 237110. 238220 is for building plumbing/HVAC work.
What is the NAICS code for a plumbing LLC?
“LLC” is a legal structure, not an industry category. A plumbing LLC can have different NAICS codes depending on what it actually does at the establishment.
Core NAICS codes for plumbing contractors and related businesses
Primary plumbing & HVAC code
For most plumbing contractors (and many HVAC contractors), the primary NAICS code is:
Covers building-system installation and service: plumbing fixtures, piping, drains, boilers/hydronic systems, and HVAC equipment installation/service.
Commonly confused related codes
- 238210 – Electrical Contractors and Other Wiring Installation Contractors
- 237110 – Water and Sewer Line and Related Structures Construction
- 562991 – Septic Tank and Related Services
- 238290 – Other Building Equipment Contractors
Use the most specific match possible: if the primary activity is civil utility lines (237110) or septic services (562991), those should be used instead of 238220.
NAICS hierarchy (reference)
View the NAICS hierarchy for plumbing contractors (238220)
Use this list when you know the general category but need the correct level (sector, subsector, or industry).
| Category | NAICS | What it covers |
|---|---|---|
| Sector | 23 | Construction |
| Subsector | 238 | Specialty Trade Contractors |
| Industry group | 2382 | Building Equipment Contractors |
| U.S. industry | 238220 | Plumbing, Heating, and Air-Conditioning Contractors |
Hybrid businesses: If a company does plumbing, HVAC, and electrical work, classify by the activity representing the majority of economic output.
Best practice: keep a short internal note (1–2 sentences) explaining what was selected and what was excluded for repeatability.
Common plumbing contractor business types (and the NAICS code used)
Residential plumbing service & repair:
Typically 238220.
Commercial plumbing installation:
Typically 238220.
HVAC installation & service contractor:
Commonly 238220 when building-system work is the primary activity.
Drain cleaning company:
Often 238220 if performed as part of plumbing service/repair.
Septic pumping / septic cleaning service:
Commonly 562991 when septic tank service is the primary activity.
Common plumbing-adjacent activities outside NAICS 238220
Some businesses market “plumbing” but are primarily civil construction, waste services, or equipment-focused contracting. Classification follows the dominant activity.
Water & sewer line construction
Used for municipal mains, trenching, utility-line installation, and related civil structures.
Septic tank and related services
Used when pumping/cleaning septic tanks and related waste-handling services are the primary business.
Applied uses of plumbing NAICS codes
- Licensing, vendor onboarding, and compliance classification fields
- Insurance underwriting and risk segmentation (trade contractor risk)
- Government contracting registration and bid eligibility workflows
- Market sizing, peer benchmarking, and industry rollups
- Business database indexing and segmentation by primary activity
Plumbing contractor industry data and business lists
Need a plumbing contractor list by NAICS code?
SICCODE.com provides business lists aligned to NAICS classifications, including 238220. Lists can be filtered by NAICS, geography (state, county, ZIP), company size, and other firmographic fields, with delivery options including CSV, Excel, and structured formats for integration workflows.
FAQ
- What is the NAICS code for plumbing contractors?
The NAICS code for plumbing contractors is most commonly 238220. - Does 238220 include HVAC contractors?
Yes. 238220 covers plumbing, heating, and air-conditioning contractors when building-system installation/service is the primary activity. - Is drain cleaning included under 238220?
Often yes when performed as part of plumbing service/repair. Classification depends on the establishment’s primary activity. - Is municipal water/sewer line work classified under 238220?
Usually no. Civil water and sewer line construction is typically 237110. - What if a business does plumbing and electrical work?
Use the NAICS code that matches the dominant activity (largest share of revenue/work) for that establishment.
Next steps
Start with NAICS 238220, then confirm whether the primary activity is building plumbing/HVAC work (238220) versus civil utility lines (237110) or septic services (562991).
Related resources
- NAICS Code Lookup Directory
- What Is a NAICS Code?
- NAICS Included vs. Excluded Activities
- SIC Codes vs NAICS Codes
Citation
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