Lead-Free Plumbing Requirements: What the 0.25% Law Actually Means
Lead-free plumbing requirements come from one federal rule: the Safe Drinking Water Act, as amended by the Reduction of Lead in Drinking Water Act, caps the lead content of any pipe, fitting, or fixture used for drinking water at a weighted average of 0.25% across its wetted surfaces, and caps solder and flux at 0.2% lead. The limit took effect January 4, 2014, and applies to what you install or repair, not just what a factory makes. Here is what qualifies and how to prove it.
The 0.25% lead-free law, in plain terms
The federal lead-free standard is a weighted average of 0.25% lead across the wetted surfaces of pipes, pipe fittings, plumbing fittings, and fixtures, plus a separate 0.2% lead limit for solder and flux. It comes from Section 1417 of the Safe Drinking Water Act (SDWA), as revised by the Reduction of Lead in Drinking Water Act (RLDWA). The rule is enforced by the EPA. “Lead free” is a legal term of art here, not a promise of zero lead.
The number matters because the old ceiling was far higher. Before January 4, 2014, “lead free” brass and bronze could contain up to 8% lead by weight, per the EPA. The RLDWA dropped that to 0.25% on wetted surfaces, a roughly 32-fold cut in allowed lead for the metal that touches your water. Solder had already been held to 0.2% since the 1986 lead-solder ban.
The law binds installers and repairers, not only manufacturers. The SDWA prohibits the use of any non-lead-free pipe, fitting, fixture, solder, or flux in the installation or repair of a public water system, or of any plumbing in a residential or nonresidential building that provides water for human consumption. In practice that means a plumber who solders a potable line with 50/50 solder, or drops in a high-lead valve, is out of compliance even if the part was sitting on a shelf.
Manufacturers picked up a separate duty later. As of September 1, 2023, makers and importers who introduce covered plumbing products into commerce must have them certified as lead free by an accredited third party, per the EPA’s implementation rule. That is why newer parts increasingly carry a visible certification mark rather than just a manufacturer’s claim.
NSF/ANSI 61 and NSF/ANSI 372: what each one proves
Two standards do the certifying, and they answer different questions. NSF/ANSI 61 is a leachate test: it measures how much lead and other contaminants a finished product releases into water. NSF/ANSI 372 is a material-content test: it confirms a product meets the 0.25% weighted-average lead limit written into the law. Many potable-water parts carry both marks, but 372 is the one tied directly to the lead-free statute.
NSF/ANSI 61 casts a wider net. It exposes products to pH 5 and pH 10 test waters at set temperatures and analyzes the leachate for regulated metals including antimony, arsenic, barium, cadmium, chromium, copper, lead, mercury, selenium, thallium, and nickel, per Merit Brass. It answers “what comes out of this part in service,” which is broader than lead alone.
NSF/ANSI 372 answers “how much lead is in the wetted metal.” It supplies the formula for the weighted-average calculation and the procedure for lead-content testing that determines whether a part clears 0.25%. When the SDWA was amended, that lead-content check was moved into 372 as the reference document, per Merit Brass. If a jurisdiction or a spec calls out the lead-free law specifically, 372 is the mark that satisfies it.
A newer wrinkle sits on top of 61. Endpoint drinking-water devices such as kitchen and lavatory faucets now carry an NSF/ANSI/CAN 61: Q ≤ 1 mark, a tighter lead-leaching limit that became mandatory January 1, 2024, per Safe Water Engineering. Components in the final liter of the system, like connector hoses and stop valves, target Q ≤ 0.5. When you buy a drinking-water faucet, that Q ≤ 1 mark is the current thing to look for.
Which pipe, fittings, solder, and fixtures qualify
A part qualifies as lead free when its wetted metal meets the 0.25% weighted average (0.2% for solder and flux) and it carries a matching certification mark. The table below maps the common components to the standard that applies and the mark to look for. Treat it as a buying and spec-checking guide; your state or local code may reference these standards differently, so confirm locally.
| Component | Standard to look for | What to look for on the part or box |
|---|---|---|
| Copper tube (Type L, M, K) | Inherently lead free; NSF/ANSI 61 for potable use | Copper itself carries no lead; verify tube stamped to ASTM B88 and rated potable |
| PEX and CPVC pipe | NSF/ANSI 61 | “NSF-pw” or “NSF-61” printed on the pipe run |
| Brass fittings, valves, adapters | NSF/ANSI 372 (often plus 61) | “NSF-372,” “lead free,” or “LF” cast or stamped on the body |
| Solder (potable joints) | 0.2% lead limit; ASTM B32 lead-free solder | Spool marked “lead free” (commonly 95/5 or no-lead alloy), never 50/50 |
| Flux | 0.2% lead limit; lead-free flux | Container marked “lead free” |
| Kitchen and bath faucets (endpoint) | NSF/ANSI/CAN 61: Q ≤ 1 | “NSF/ANSI/CAN 61: Q ≤ 1” on packaging (mandatory since Jan 1, 2024) |
| Connector hoses, stop valves (final liter) | NSF/ANSI/CAN 61: Q ≤ 0.5 | Q ≤ 0.5 marking on the component or box |
| Water heater (potable connections) | NSF/ANSI 372 on wetted fittings and nipples | Lead-free stamped dielectric nipples and supply connectors |
The practical rule for a repipe or a repair: if metal touches drinking water, it needs a lead-free credential, and any joint you solder needs lead-free solder and flux. Copper tube and most modern plastics clear the bar on their own, so the parts to watch are brass and bronze fittings and valves, where lead was historically added for machinability. For how those material choices play into a whole-house job, see what a full repipe costs.
How the weighted average is actually calculated
The 0.25% figure is a weighted average, not a per-part maximum, because a fitting is made of several wetted pieces with different lead content. The calculation multiplies the lead percentage of each wetted component by that component’s share of the total wetted surface area, then adds the results. A small brass seat with slightly higher lead can pass if the large wetted surfaces around it are near zero.
Here is the method in order, drawn from the NSF/ANSI 372 procedure the law references:
- Identify every wetted component of the product, meaning each surface that contacts water in normal use.
- Measure the wetted surface area of each component and total them.
- Determine the lead content percentage of each wetted component.
- For each component, multiply its lead percentage by its share of the total wetted surface area.
- Add those weighted values together. The sum must be 0.25% or less to qualify.
You will never run this math at a job site, and you should not have to. It is the manufacturer’s and certifier’s job, which is exactly why the certification mark exists: the NSF/ANSI 372 stamp means an accredited lab already ran this calculation and the part cleared. Your job is to read the mark, not recompute it.
What is exempt, and why “exempt” is not “safe”
The lead-free requirements do not cover every device. The SDWA exempts products used exclusively for nonpotable service, plus a specific statutory list: toilets, bidets, urinals, fill valves, flushometer valves, fire hydrants, tub fillers, shower valves, service saddles, and water distribution main gate valves 2 inches in diameter or larger. These were carved out because they either do not deliver drinking water or serve functions Congress treated separately.
Exempt is a legal status, not a safety verdict. Many manufacturers now sell low-lead versions of exempt items anyway, and some states set stricter rules than the federal floor. California and Vermont, for example, moved to a 0.25% low-lead standard ahead of the federal date, and California’s DTSC maintains its own low-lead plumbing requirements. Because the SDWA is a floor rather than a ceiling, always check whether your state or local code pulls exempt items back into scope.
One category worth flagging: an exempt fixture can still sit downstream of non-exempt supply parts that must comply. A shower valve may be exempt, but the fittings and stops feeding it are not. If you are working on hot-water fixtures, the supply side still has to be lead free, which overlaps with water heater code requirements for the connections at the tank.
Lead-free parts vs. lead service lines
The lead-free law governs the parts inside a building’s plumbing. A separate EPA rule governs the lead service line running from the street to the meter, and the two are often confused. Meeting the 0.25% standard on your new fittings does nothing about an old lead service line, which is a bigger source of lead exposure and is being addressed under its own mandate.
That mandate is the Lead and Copper Rule Improvements, which pushes utilities toward replacing lead service lines nationwide on a set timeline. If your home predates the mid-1980s, the service line is the first thing to check, ahead of any fitting swap. For the replacement mandate, who pays, and the timeline, see the EPA rule forcing lead service line replacement. Lead-free fittings and lead-line replacement work together; neither one substitutes for the other.
The bottom line for installers and owners
If a part touches drinking water, it has to be lead free: a weighted average of 0.25% lead or less on wetted surfaces, 0.2% for solder and flux, verified by an NSF/ANSI 372 mark and, for endpoint faucets, an NSF/ANSI/CAN 61: Q ≤ 1 mark. The obligation attaches to installation and repair after January 4, 2014, so it lands on the person doing the work, not just the factory. Watch the brass, use lead-free solder and flux, read the mark before you buy, and confirm your state or local code, which may go further than the federal floor.
Frequently asked questions
Does “lead free” plumbing mean zero lead?
No. Under the federal Safe Drinking Water Act, “lead free” means a weighted average of no more than 0.25% lead across the wetted surfaces of pipes, fittings, and fixtures, and no more than 0.2% lead in solder and flux. That is a very low limit, not zero. Older brass and bronze parts were allowed up to 8% lead before 2014.
What is the difference between NSF/ANSI 61 and NSF/ANSI 372?
NSF/ANSI 61 is a leachate test that checks how much lead and other contaminants a product releases into water. NSF/ANSI 372 is a material-content test that proves a product meets the 0.25% weighted-average lead limit. A part can carry both. To confirm the lead-free law specifically, look for the 372 mark or an “NSF-372” or “lead free” stamp.
Do I have to replace my existing brass fittings to meet the lead-free law?
Not usually. The federal law applies to pipes, fittings, solder, and fixtures installed or repaired after January 4, 2014. Parts already in place before that date are generally not required to be torn out by the statute. If you are replacing or repairing a potable-water part now, the new part must be lead free, and any solder you use must meet the 0.2% limit.
Are any plumbing products exempt from the lead-free requirements?
Yes. The law exempts devices used exclusively for nonpotable service, plus a specific list: toilets, bidets, urinals, fill valves, flushometer valves, fire hydrants, tub fillers, shower valves, service saddles, and water distribution main gate valves 2 inches in diameter or larger. Exempt still means many manufacturers sell low-lead versions anyway, so check the part.
How do I know if a faucet is lead free before I buy it?
Check the packaging and the product markings, not just the listing photo. Look for NSF/ANSI 372, “lead free,” or the newer NSF/ANSI/CAN 61: Q ≤ 1 mark that endpoint drinking-water faucets have carried since January 1, 2024. If a faucet shows no lead-related certification and is sold for drinking water, treat that as a red flag and pick a certified model.
Last reviewed: August 2026.