Guides / Compliance

NSF/ANSI 61 and 372: What They Mean for a Brass Part

September 21, 2026

If a brass part touches drinking water in the United States, two standards decide what it can be made of before any engineering question is asked. They are often quoted together and they do different jobs.

NSF/ANSI 372: the lead content rule

This is the arithmetic one.

Federal law, through the Safe Drinking Water Act as amended, requires that pipes, fittings and fixtures conveying water for human consumption have a weighted average lead content of not more than 0.25 percent across their wetted surfaces. NSF/ANSI 372 is the standard that defines how you establish and verify that number. Solder and flux carry a separate limit of 0.2 percent.

The word doing the work is weighted. It is not a rule that every material in the assembly must be under 0.25 percent lead. Each wetted component is weighted by its share of the total wetted surface area, and the weighted result across the whole assembly must land under the limit.

On a single machined fitting this distinction rarely helps, because one alloy is almost all of the wetted surface. On a larger assembly with a compliant body and a small leaded component, the calculation is worth doing properly rather than assuming. We built a weighted average lead calculator that does the arithmetic in your browser.

C360 free-cutting brass carries roughly 2.5 to 3.7 percent lead. It is more than ten times over the line on its own, which is why the alloy question is settled before anything else on a potable water part.

NSF/ANSI 61: the health effects standard

This one is not arithmetic. It is testing.

NSF/ANSI 61 asks a broader question: what does this material actually leach into the water it touches, across everything it might contain, not only lead. A material passes by being exposed under a defined protocol and having the extraction water analysed.

That difference matters in three ways.

You cannot calculate your way to NSF 61 from a composition. You test.

Certification attaches to a product made by a named manufacturer at a named facility, not to an alloy and not to a drawing. Buying compliant bar does not produce a certified part.

A part can meet 372 on lead content and still need 61 work, because they answer different questions.

What a machine shop can and cannot give you

This is where expectations most often break, so it is worth being blunt.

A shop can: buy a compliant alloy, supply the mill certificate that proves its composition, machine to your print, and control the process so nothing contaminates the part.

A shop cannot: certify your product to NSF 61 or 372. Certification is granted by an accredited certification body to the manufacturer that puts the product on the market. That is you, not the machine shop.

Any supplier who tells you they will supply NSF certified parts is either describing certification they hold for their own catalogue product, or misunderstanding the question. On a custom machined part, ask instead for the alloy, the mill certificate, and evidence they have shipped this class of part before.

That is also why this site never claims certification. We match your RFQ with shops that run lead-free brass and can supply certificates. The certification path is yours.

Which alloys actually clear the bar

Alloy	Lead, nominal %	Machinability	Note
C69300 silicon brass	under 0.09	80	The usual answer. Roughly twice the strength of C360 and highly dezincification resistant
Bismuth brass, C49300 family	under 0.25	80	Closest behaviour to C360, thinner stock availability
C360 free-cutting	2.5 to 3.7	100	Not compliant for wetted potable water parts

Published typical values for the alloy. They describe the material, not a promise from any shop.

Note that C69300 is not only a compliance answer. It is a genuinely better alloy for hot water service because it resists dezincification, which ordinary yellow brass does not. See dezincification resistant brass.

What to write on the drawing

The instinct is to write an alloy name. That is the weaker option.

Weaker: Material: C69300

Better:

Wetted component, potable water service.
Material shall comply with NSF/ANSI 372
(0.25 percent weighted average lead, wetted surfaces).
Suggested alloy: C69300 or equivalent lead-free brass.
Mill certificate EN 10204 3.1 required with each lot.

The second version states the requirement and leaves the shop free to offer whichever compliant bar it can actually source that week. On a repeating part, that freedom is worth real money, because lead-free stock availability is thinner than C360 and a single named alloy can put you on a long lead time for no engineering reason.

Say separately whether you need a certificate per lot or only with the first article. Those are priced very differently. See material certificates for brass parts.

Outside the United States

Europe does not have one equivalent list. Drinking water materials are approved nationally, and the UK, Germany, France and the Netherlands each run their own scheme, with work ongoing to align them under the recast Drinking Water Directive. In practice a part designed to clear NSF 372 on lead content is usually in a good position, but the national approval is still a separate exercise.

Note also that RoHS exemption 6(c), which is often mentioned in the same conversation, does not apply here at all. It covers electrical and electronic equipment, not plumbing. See RoHS exemption 6(c) and leaded brass in 2027.

This page describes the standards as they stood in September 2026 and is not legal advice.

Have a potable water part to quote? Send the drawing and set the compliance field to NSF/ANSI 61 and 372. We only match it to shops that run lead-free brass.

Frequently asked questions

Keep reading

• Leaded and Lead-Free Brass Compared, and the Standards That Decide It
• RoHS Exemption 6(c) and What Happens to Leaded Brass in 2027