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NSF/ANSI/CAN 372 (lead content)

Entry in Sizes, codes and marks · Updated · Written by the Know Your Pipes editors from the sources listed under References

NSF 372, formally NSF/ANSI/CAN 372, Drinking Water System Components – Lead Content, is the standard used to certify that pipes, fittings and fixtures meet the US lead-free limit[1][2]. It checks lead content only, not other contaminants.

The 2024 edition was published on June 10, 2024, replacing the 2022 edition, and covers components that carry or dispense water for drinking or cooking[1].

1 The lead-free limit

The Safe Drinking Water Act sets the legal meaning of "lead free." Under the 1986 amendments, solder and flux could contain no more than 0.2% lead and pipes no more than 8%[3]. A 2011 federal law, the Reduction of Lead in Drinking Water Act, changed the pipe limit to a weighted average of 0.25% lead across wetted surfaces; the solder and flux limit stayed at 0.2%[3].

"Weighted average" means lead content is calculated across all the wetted surfaces of a product as a whole rather than part by part[3]. NSF/ANSI/CAN 372 certification shows a product meets this limit, with solder and flux under 0.2%[2].

Lead limits in US drinking water plumbing[2][3]
Item1986 limitLimit since 2011 law
Pipes, fittings, fixtures8% lead0.25% weighted average on wetted surfaces
Solder and flux0.2% lead0.2% lead

2 Certification and marks

EPA's 2020 lead-free rule requires manufacturers and importers to certify their products; EPA states that certification has been required since September 2023[3]. EPA lists eight ANSI-accredited third-party certification bodies, each with its own mark and required identifier text, such as "NSF/ANSI/CAN 372" or "NSF/ANSI 372" next to the mark[2]. Some certifiers use other wording; one notes that "Low Lead Content" signifies compliance with 372[2].

Since October 2017, NSF/ANSI/CAN 61 has required compliance with 372 for products not exempted by law, so a current 61 mark also covers lead content[2]. Before then, only a 372 mark or the now-retired NSF 61 Annex G mark (identifier text such as "NSF/ANSI 61-G") showed lead-free compliance[2]. Products made before the change may still be for sale, and EPA suggests checking the certifier's online listing when a product is marked "NSF 61" alone[2].

Some states set their own low-lead rules; one fitting maker cites California Health and Safety Code Section 116875 as an example its products meet[4].

3 Exemptions and existing plumbing

The federal rule lists exempt products, including toilets, bidets, urinals, fill valves, flushometer valves, tub fillers, shower valves, service saddles, fire hydrants, and gate valves on water distribution mains that measure 2 inches or more across[3]. The rule does not require homeowners to replace existing plumbing; it applies to new installations and repairs[5].

Related entries: lead-free solder, brass fittings and dezincification and lead pipe.

See also

  • Lead-free solderSolder and flux with no more than 0.2% lead, the only kind allowed on US drinking-water plumbing since 1986.
  • Shutoff valvesThe valves that stop water in a house: ball, gate and fixture stop valves, how they differ, and the rules that apply to them.
  • NSF/ANSI/CAN 61The health-effects standard for products that touch drinking water: what NSF 61 tests, what it covers and where codes require it.
  • Brass fittings and dezincificationBrass is a copper-zinc alloy used for valves and fittings; dezincification is corrosion that removes its zinc.
  • Nominal pipe size, CTS and IPSWhy pipe sizes are names rather than measurements, and how the CTS and IPS outside-diameter systems differ for the same nominal size.
  • Pipe sizing basics for housesHow water supply pipe sizes for a house are chosen: code minimums, flow, velocity and pressure, and why the job belongs to a plumber.

References

  1. Standards Council of Canada, "NSF/ANSI/CAN 372-2024: Drinking Water System Components – Lead Content" — ccn-scc.ca
  2. U.S. Environmental Protection Agency, "How to Identify Lead Free Certification Marks for Pipes, Fittings, Fixtures, Solder, and Flux Used for Drinking Water" (revised June 2024) — epa.gov
  3. U.S. Environmental Protection Agency, "Use of Lead Free Pipes, Fittings, Fixtures, Solder, and Flux for Drinking Water" — epa.gov
  4. Spears Manufacturing, "Appendix C: Product Approvals and Certifications" — spearsmfg.com
  5. U.S. Environmental Protection Agency, "Questions and Answers about the Final Lead Free Rule" — epa.gov