Inorganics · CAS 14797-55-8
Nitrate in Tap Water
Nitrate is a nitrogen compound that enters water mainly from fertilizer, animal waste, and septic systems — one of the most common contaminants in agricultural areas.
Substance identity
- Scientific name
- Nitrate (as N)
- Family
- Inorganics
- CAS number
- 14797-55-8
This guide explains the compound. Only a water-system record or household test can tell you whether it appears in your water.
- Federal reference
- 10 mg/L as nitrogen (MCL)Enforceable maximum contaminant level
- Health-based goal
- 10 mg/L (as N) federal limit (MCL)US EPA Nitrate/Nitrite Rule
- Measurement context
- Stated in the recordThis contaminant is tracked through federal and state compliance monitoring. Private wells near farmland should be tested, especially before use by infants. PurityMap does not yet publish a per-system measured value for Nitrate; this page is a reference explainer. To learn what is in your own water, check your utility’s Consumer Confidence Report (CCR) or use a certified home test.
- Cities on record
- None yetUS cities in PurityMap's published record where Nitrate 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 Nitrate?
Nitrate is a nitrogen compound that enters water mainly from fertilizer, animal waste, and septic systems — one of the most common contaminants in agricultural areas.
Where Nitrate comes from
Runoff and leaching from fertilizer, manure, and septic systems into groundwater and surface water.
- Agricultural fertilizer
- Animal feedlots and manure
- Septic systems
Most affected: Infants under six months (risk of methemoglobinemia, "blue-baby syndrome") and pregnant people.
How Nitrate is measured
This contaminant is tracked through federal and state compliance monitoring. Private wells near farmland should be tested, especially before use by infants. PurityMap does not yet publish a per-system measured value for Nitrate; this page is a reference explainer. To learn what is in your own water, check your utility’s Consumer Confidence Report (CCR) or use a certified home test.
Why context mattersHow PurityMap reads a Nitrate 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 Nitrate is found across the U.S.
These are the places in PurityMap’s published record where Nitrate appears on a water system’s monitoring results. It reflects the systems and sampling we track, not a national prevalence estimate.
PurityMap has no city on record with Nitrate on its monitoring results yet. This fills in as monitoring data is published — a substance that was never tested is shown as pending, never as a pass.
Treatment capability, if a finding establishes a need
The formats that commonly hold a verified reduction claim for Nitrate are Reverse osmosis, Anion exchange, Distillation. 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 Nitrate?
Nitrate is a nitrogen compound that enters water mainly from fertilizer, animal waste, and septic systems — one of the most common contaminants in agricultural areas.
What is the limit for Nitrate in drinking water?
The enforceable federal limit is 10 mg/L as nitrogen (MCL). The health-based goal is 10 mg/L (as N) federal limit (MCL). PurityMap reads every measurement against its stated benchmark and never sets its own.
Where does Nitrate in tap water come from?
Agricultural fertilizer, Animal feedlots and manure, Septic systems.
Why does Nitrate matter?
High nitrate is an acute risk for infants — it interferes with the blood’s ability to carry oxygen. Levels can spike seasonally with irrigation and rainfall, so one low reading is not a guarantee. Boiling concentrates nitrate rather than removing it.
How do you remove Nitrate from water?
Treatment technologies commonly certified to reduce Nitrate include Reverse osmosis, Anion exchange, Distillation. Match the exact certified claim to your water before buying — holding a format is not the same as holding the claim.
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 →