NAICS 423720

Overview

The North American Industry Classification System (NAICS) is the framework U.S. federal statistical agencies use to classify business establishments for collecting, analyzing, and publishing data on the U.S. economy. Created under the Office of Management and Budget and adopted in 1997, NAICS was jointly developed with Statistics Canada and Mexico’s INEGI to ensure comparability across North America. The current revision cycle yields a 2022 “vintage.” ¹

NAICS 423720 covers merchant wholesalers primarily engaged in distributing plumbing equipment, hydronic heating equipment, household-type water heaters, and related supplies. Federal statistical publications (e.g., the Economic Census and Annual Wholesale Trade Survey) tabulate data for this code within Sector 42 (Wholesale Trade), supporting market sizing and benchmarking. ²

See also on G2X:

• G2X — NAICS 423720 overview
• G2X — NAICS 423730
• G2X — NAICS 423740

What this NAICS covers

• Merchant wholesale distribution of plumbing equipment and supplies. ²
• Merchant wholesale distribution of hydronic heating equipment. ²
• Merchant wholesale distribution of household-type water heaters. ²
• Merchant wholesale distribution of plumbing and heating valves and fittings. ³
• Wholesaling activities within Industry Group 4237 tied to plumbing/heating (hydronics) channels. ²
• Operations consistent with merchant wholesalers (warehouse/office-based, business-to-business). ²

Related NAICS and PSC codes

NAICS titles per the 2017 NAICS United States Manual. ²
PSC titles per the PSC Manual (April 2025). ⁴

What this NAICS excludes

• Warm air heating and air-conditioning equipment wholesaling—classified under 423730. ²
• Refrigeration equipment wholesaling (except household-type refrigerators/freezers)—classified under 423740. ²
• Selling and installing as contractors—classified under 238220. ²
• Household-type gas and electric appliances (except water heaters and noncooking heating stoves)—classified under 423620. ²

NAICS 2022 vintage and data availability

Census programs are transitioning to the 2022 NAICS vintage; Economic Census 2022 releases and other series are publishing or restating estimates on this basis per program schedules. Users can reference Sector 42 (Wholesale Trade) tables for industry-level statistics aligned to 2022 NAICS. ⁵

Frequently asked questions

• What businesses fall under NAICS 423720?
  Establishments primarily engaged in merchant wholesaling of plumbing equipment, hydronic heating equipment, household-type water heaters, and related supplies. This code sits within Industry Group 4237 for hardware and plumbing/heating categories. ²

• How is NAICS 423720 different from 423730 and 423740?
  423720 covers hydronics and plumbing-focused wholesaling; 423730 covers warm air heating and air-conditioning equipment; 423740 covers refrigeration equipment (excluding household-type refrigerators/freezers). Each targets distinct distribution channels and product lines. ²

• Does NAICS 423720 include household appliances?
  Generally no. Household-type gas and electric appliances (e.g., room A/C, clothes dryers) are classified in 423620, except that household-type water heaters remain in 423720. ²

• Where are official statistics for NAICS 423720 published?
  Census Economic Census releases include Sector 42 tables with industry-level estimates; the Annual Wholesale Trade Survey publishes national wholesale metrics that encompass 4237 industries. ⁶

• What is meant by “2022 NAICS vintage” in current releases?
  It denotes the latest revision of NAICS used for dissemination. Census began publishing on the 2022 basis (e.g., Economic Census First Look in 2024) and plans full adoption across programs by the end of calendar year 2027. ⁵

Useful resources

• G2X — NAICS 423720 overview
• Census NAICS search and introduction (general NAICS background and 1997 adoption). ¹
• 2017 NAICS United States Manual (industry definitions and cross-references). ²
• 2022 NAICS Sector 42 — Wholesale Trade (Economic Census tables and files). ⁶
• Census implementation of the 2022 NAICS vintage (timeline and scope). ⁵

References

1. U.S. Census Bureau, NAICS search/introduction (definition and 1997 adoption). https://www.census.gov/naics/?input=423720&year=2022
2. U.S. Census Bureau, 2017 NAICS United States Manual (NAICS 423720 definitions and cross-references). https://www.census.gov/naics/reference_files_tools/2017_NAICS_Manual.pdf
3. U.S. Census Bureau (2007 reference), 4238405 cross-reference noting plumbing/heating valves and fittings are classified in NAICS 423720. https://www2.census.gov/econ2007/Reference_materials/htm%20files/4238405.htm
4. General Services Administration, Product and Service Codes (PSC) Manual, April 2025. https://www.acquisition.gov/sites/default/files/manual/PSC%20Manual%20April%202025.pdf
5. U.S. Census Bureau, The Census Bureau’s Implementation of the 2022 NAICS. https://www.census.gov/library/reference/code-lists/naics/2022/implementation-timeline.html
6. U.S. Census Bureau, 2022 NAICS Sector 42 — Wholesale Trade (Economic Census). https://www.census.gov/data/tables/2022/econ/economic-census/naics-sector-42.html