2022 NAICS national industry in sector 42 Wholesale Trade
423720 Plumbing and Heating Equipment and Supplies (Hydronics) Merchant Wholesalers
NAICS 423720 is the US industry code for plumbing and heating equipment and supplies (hydronics) merchant wholesalers. It covers establishments primarily engaged in the merchant wholesale distribution of plumbing equipment, hydronic heating equipment, household-type water heaters, and/or supplies.
- Code
- 423720 (2022 NAICS)
- Title
- Plumbing and Heating Equipment and Supplies (Hydronics) Merchant Wholesalers
- Part of
- Hardware, and Plumbing and Heating Equipment and Supplies Merchant Wholesalers
- SBA small business limit
- Up to 200 employees
- Closest UK SIC
- 46630 (details)
Changes coming. The NAICS 2027 revision applies to data from 1 January 2027, and SBA proposed new size standards on 20 August 2026. The values on this page are the ones in force today; we update this page when the official files change.
Official definition
This industry comprises establishments primarily engaged in the merchant wholesale distribution of plumbing equipment, hydronic heating equipment, household-type water heaters, and/or supplies.
When to use a different code
Census classifies these close-sounding activities somewhere else. Businesses mainly engaged in:
- Selling and installing plumbing, heating, and air-conditioning equipment are classified in Industry 238220, Plumbing, Heating, and Air-Conditioning Contractors.
- Merchant wholesale distribution of warm air heating and air-conditioning equipment--are lclassified in Industry 423730, Warm Air Heating and Air-Conditioning Equipment and Supplies Merchant Wholesalers.
- Merchant wholesale distribution of household-type gas and electric appliances (except water heaters and heating stoves (i.e., noncooking)), room air-conditioners, clothes dryers, and/or household-type audio or video equipment are classified in Industry 423620, Household Appliances, Electric Housewares, and Consumer Electronics Merchant Wholesalers.
Activities listed under 423720
The Census index assigns these 37 activities to this code. If your business matches one, this is your code.
- Bathtubs merchant wholesalers
- Boilers (e.g., heating, hot water, power, steam) merchant wholesalers
- Brass goods, plumbers', merchant wholesalers
- Burners, fuel oil and distillate oil, merchant wholesalers
- Convectors merchant wholesalers
- Drinking fountains (except refrigerated) merchant wholesalers
- Fireplaces, gas, merchant wholesalers
- Fireplaces, prefabricated gas, merchant wholesalers
- Fittings and valves, plumbers', merchant wholesalers
- Fountains, drinking (except refrigerated), merchant wholesalers
- Furnaces (except forced air), heating, merchant wholesalers
- Gas fireplaces merchant wholesalers
- Gas hot water heaters merchant wholesalers
- Heating boilers, steam and hot water, merchant wholesalers
- Heating equipment, hot water, merchant wholesalers
- Hydronic heating equipment and supplies merchant wholesalers
- Lavatory fixtures merchant wholesalers
- Oil burners, heating, merchant wholesalers
- Pipe and boiler coverings merchant wholesalers
- Pipe fittings and valves, plumbers', merchant wholesalers
- Plumbers' brass goods merchant wholesalers
- Plumbing and heating valves merchant wholesalers
- Plumbing equipment merchant wholesalers
- Plumbing fixtures merchant wholesalers
- Plumbing supplies merchant wholesalers
- Radiators, heating, nonelectric, merchant wholesalers
- Sanitary ware, china or enameled iron, merchant wholesalers
- Sinks merchant wholesalers
- Solar heating panels and equipment merchant wholesalers
- Spa equipment merchant wholesalers
- Stoves (i.e., noncooking), heating, merchant wholesalers
- Toilet bowls and tanks merchant wholesalers
- Urinals merchant wholesalers
- Valves, plumbing and heating, merchant wholesalers
- Water heaters, gas and electric, merchant wholesaler
- Water purification equipment, household-type, merchant wholesalers
- Water softening and conditioning equipment merchant wholesalers
SBA size standard for 423720
To count as a small business for SBA loans and federal contracts under NAICS 423720, your business (including affiliates) must not exceed 200 employees. Check your business.
Source: SBA table of size standards, effective March 17, 2023.
Closest UK SIC 2007 codes
There is no official one-to-one link between NAICS and UK SIC. These codes share the same international class (ISIC Rev. 4: 4659, 4663), so treat them as a starting point and check the definition.
Built from Census concordances 2022→2017 NAICS and 2017 NAICS→ISIC Rev. 4.
Similar codes to compare
Data last changed November 14, 2026. How this page is built.