Three questions most water testing guides don’t answer plainly. This guide does, starting with who actually needs testing and finishing with what to do when the results come back.
Lead solder ban year
Buildings constructed before 1986 almost certainly have lead-tin solder at some pipe joints. Young children and pregnant people face the greatest developmental risk from lead exposure. A first-draw test at the kitchen sink and primary bathroom sink is the appropriate starting point. Until results are in, run cold water 60 seconds before collecting, use cold water only, and consider a faucet filter certified NSF 53 for lead at the kitchen tap.
Adult lead exposure from drinking water at levels common in pre-1986 buildings poses lower but not zero risk. Cardiovascular effects of chronic low-level lead exposure are documented in adults. Running cold water before use and using cold water for all drinking and cooking is a free precautionary step that makes sense regardless of testing status.
Buildings fully constructed after 1986 are required to use lead-free solder (<0.2% lead). However, some fixture valves and fittings sold as “lead free” prior to 2014 contained up to 8% lead by weight under an older legal definition. If your building was constructed between 1986 and 2014, there is still a basis for testing at primary use fixtures if you want certainty.
A formula-fed infant receives 100% of their fluid intake from prepared formula, meaning the formula preparation water source matters more for infants than any other age group. Test the specific kitchen tap used for formula preparation with a first-draw protocol. While awaiting results, flush 30–60 seconds before collecting and use a certified NSF 53 filter.
8–18 hours stagnation. Cold tap only. First water from the fixture collected in pre-acidified container without running. Most informative for identifying branch-line and solder contribution. Appropriate for: pre-1986 residential buildings, formula preparation points, regulatory compliance testing. Turnaround: 7–10 business days for ICP-MS results.
First draw collected, then subsequent samples after defined flush volumes. The sequence captures different plumbing segments: fixture/branch at first draw, riser at second draw, supply line at third draw. More expensive but provides detailed source localization. Appropriate for: identifying whether lead source is the fixture, building riser, or service line. Used in regulatory investigations and professional assessments.
First-draw sample analyzed for lead, copper, iron, manganese, arsenic, and a full suite of metals. Provides a complete picture of what the plumbing is contributing, not just lead. Iron and manganese results explain discoloration events. Copper results at >0.9 mg/L warrant further investigation of corrosion. Appropriate for: comprehensive baseline testing, brownstone owners, or building managers wanting a full snapshot.
Required by NYC Article 47 for child care facilities, by NYS Education Law for schools, and by EPA LCRR for water systems. Must be conducted by a certified professional, submitted to a NY ELAP-accredited laboratory, and documented with a chain of custody form. Results are reported to the regulatory authority and the facility. Action level exceedances trigger mandatory notifications and follow-up.
Lead results are reported in micrograms per liter (mcg/L) or parts per billion (ppb). The same number.
The plumbing at this point under these stagnation conditions did not contribute detectable lead to the water sample. The most favorable result. Continue flushing before use as a routine habit.
Lead is present but below the regulatory action trigger. For households with young children or pregnant people, EPA advises precautionary measures at any detectable level. NSF 53 filter recommended at this point. Consider retesting other fixtures.
Do not use this water for drinking, cooking, or formula preparation without a certified NSF 53 or NSF 58 filter or alternative source. Identify additional fixtures. Compare first draw with flush results to locate the source. Professional building assessment warranted.
This stagnation period allows water to sit in contact with your specific branch plumbing. Do not run a dishwasher, washing machine, or toilet — anything that draws water from the same supply resets the stagnation clock.
Remove the aerator screen if any before collecting to avoid it trapping the sample. Fill the lab-provided sample container to the marked line. Seal immediately.
Lead samples have a preservation holding time specified by the laboratory. For EPA Method 200.8 (ICP-MS), samples must be preserved with nitric acid by the lab or delivered promptly for preservation. Follow the specific laboratory’s instructions for your kit.
EPA action level: 15 ppb (public water system regulatory trigger). NYC school action level: 15 ppb in most schools, 1 ppb in some newer programs. Health goal (MCLG): zero. Any detectable lead in a result used for a child’s primary drinking water warrants precautionary action — the regulatory thresholds are compliance tools, not safety certifications.
After implementing mitigation such as flushing protocol, certified filter, or pipe work: retest 2–4 weeks later using the same collection protocol. A follow-up test confirms whether the intervention is working at your specific fixture. Keep records of both the initial result and the follow-up for your own files.
Run cold water 30–60 seconds before any drinking or cooking water collection. Effective for branch line lead-solder sources.
Never use hot tap water for drinking, cooking, or formula. Heat accelerates lead dissolution. Always heat cold water on the stove.
A filter certified NSF/ANSI 53 specifically for lead at the kitchen cold tap provides ongoing reduction between flushes. Verify the specific lead certification.
Lead particles can accumulate in faucet aerator screens. Remove and clean monthly if your building has known lead risk in the plumbing.