NSF/ANSI/CAN 372: Lead content of materials
Official title: Drinking Water System Components - Lead Content
A materials standard. It checks how much lead is in the parts of a product that touch drinking water. It is not a claim that the product removes lead from water.
What it can cover
- Weighted average lead content of wetted surfaces: 0.25% maximum for most components
- Solder and flux: 0.2% maximum
- Faucets, valves, pipes, fittings, gaskets, coatings and water meters
- Water filters, softeners, RO systems and UV units, as products
What it does not
- Lead reduction in water. That is a claim under NSF/ANSI 53 or 58.
- Leaching of other substances. NSF says most rules also need a test such as NSF/ANSI/CAN 61, or 42, 44, 53, 55, 58 or 62 for treatment products.
The usual mistake
Reading a 372 mark on a filter as proof it removes lead. It only means the product's own parts meet the lead-free content limit.
The fine print
- NSF's 42, 53, 58 and 401 testing includes material safety with lead content checked under 372.
- Filter listings often add a footnote saying the product meets "lead free" plumbing rules under 372.
- That footnote is about the product's materials, not its performance.
Sources
- NSF/ANSI/CAN 372 Technical Requirements, NSF. Checked Oct. 4, 2026.
- NSF/ANSI 42, 53 and 401: Filtration Systems Standards, NSF. Checked Oct. 4, 2026.
- NSF/ANSI 58: Reverse Osmosis Drinking Water Treatment Systems, NSF. Checked Oct. 4, 2026.
- NSF listings for the NSF/ANSI 58 pentavalent arsenic claim (valence footnote), NSF. Checked Oct. 4, 2026.