Metals · CAS 7439-92-1
Lead in Tap Water
Lead is a toxic metal that usually enters drinking water from corrosion of lead service lines, solder, and household plumbing rather than from the source water.
Substance identity
- Scientific name
- Lead (Pb)
- Family
- Metals
- CAS number
- 7439-92-1
This guide explains the compound. Only a water-system record or household test can tell you whether it appears in your water.
- Federal reference
- Action level 15 µg/L (90th percentile)Enforceable maximum contaminant level
- Health-based goal
- 15 µg/L action level (90th percentile); MCLG of 0US EPA Lead and Copper Rule
- Measurement context
- Stated in the recordReported here from EPA Lead and Copper Rule 90th-percentile results. Your home’s result can differ; confirm with a certified tap test if you have older plumbing. PurityMap publishes this substance per water system on individual system and city-report pages, where the source dataset provides a value.
- Cities on record
- 3,759US cities in PurityMap's published record where Lead appears
A reference is a published threshold, not a safety line drawn by PurityMap. Where a result sits against it is a finding; whether that constitutes a violation is a separately published compliance field.
What is Lead?
Lead is a toxic metal that usually enters drinking water from corrosion of lead service lines, solder, and household plumbing rather than from the source water.
Where Lead comes from
Corrosion of lead pipes, solder, brass fixtures — most often within home plumbing.
- Lead service lines
- Lead solder
- Brass fixtures
Most affected: Infants and young children, and pregnant people — lead affects neurological development.
How Lead is measured
Reported here from EPA Lead and Copper Rule 90th-percentile results. Your home’s result can differ; confirm with a certified tap test if you have older plumbing. PurityMap publishes this substance per water system on individual system and city-report pages, where the source dataset provides a value.
Why context mattersHow PurityMap reads a Lead result
Evidence exceeds a reference level. Used sparingly and only when warranted.
This substance was found in the monitoring record. Being present is not the same as being above a reference level, and this signal does not say which.
Somebody looked and the laboratory reported nothing above its reporting limit. This is a result, and it is not the same as nobody looking.
No sampling for this substance has been reported for this system. Nothing is known either way, and an empty row is not a clean one.
Where the numbers come from
- A laboratory result for one sampling point
Collected under a monitoring programme, analysed by an approved method, and reported with its own detection limits.
- Read against a published reference
The reference comes from the regulator, with its own effective date. PurityMap does not set thresholds and does not adjust them.
- Attached to a system's Water Profile
Where it contributes to the published assessment alongside the evidence quality of the record it came from.
The full evidence chain →
Where Lead is found across the U.S.
These are the places in PurityMap’s published record where Lead appears on a water system’s monitoring results. It reflects the systems and sampling we track, not a national prevalence estimate.
+39 more states on record. Open any state above to see its cities.
Treatment capability, if a finding establishes a need
The formats that commonly hold a verified reduction claim for Lead are Reverse osmosis, NSF/ANSI 53 lead Certified filters, Replacing lead service lines. Holding the format is not holding the claim — the certification record is what is checked.
Boiling does not remove a dissolved chemical compound and can concentrate it. Many pitcher and refrigerator filters carry no verified claim for a compound like this at all.
Whether a system-level measurement or a household-tap measurement is the relevant scope depends on how the compound enters the water — a published characteristic of the record, not an assumption drawn here.
A finding establishes the need, the need names the capability, the capability requires a verified certification. No product appears before that sequence completes.
Filter Finder →Frequently asked questions
What is Lead?
Lead is a toxic metal that usually enters drinking water from corrosion of lead service lines, solder, and household plumbing rather than from the source water.
What is the limit for Lead in drinking water?
The enforceable federal limit is Action level 15 µg/L (90th percentile). The health-based goal is 15 µg/L action level (90th percentile); MCLG of 0. PurityMap reads every measurement against its stated benchmark and never sets its own.
Where does Lead in tap water come from?
Lead service lines, Lead solder, Brass fixtures.
Why does Lead matter?
There is no known safe level of lead. In children even low exposure can affect development and behavior; in adults it is linked to blood-pressure and kidney effects. Because lead is usually added at the tap, a system-wide result can understate risk in an individual home with older plumbing.
How do you remove Lead from water?
Treatment technologies commonly certified to reduce Lead include Reverse osmosis, NSF/ANSI 53 lead-certified filters, Replacing lead service lines. Match the exact certified claim to your water before buying — holding a format is not the same as holding the claim.
Where is Lead found in the US?
In PurityMap's published record, Lead appears in 3,759 cities across 51 states, with 25 above the federal limit. This is the scope of our record, not a national prevalence estimate.
Sources and methodology
Reference values on this page come from the governed contaminant record. Local occurrence claims stay on the linked water-system evidence pages, where sampling scope, period and source remain visible.
How PurityMap analyzes water data →