Water Knowledge

Nitrite

Summary: Nitrite (NO2−) is a fast-moving form of nitrogen that can appear when microbes convert ammonia or nitrate. It has no taste or odor and can change quickly after storms, plumbing work, or disinfection issues—so testing is the only way to know your level.

Why homeowners should care

Even small amounts of nitrite are a concern, especially for infants. It often indicates recent contamination or active microbiological processes in the well or plumbing, and it can fluctuate from week to week.

Where nitrite comes from

  • Septic or manure influence: Recent fecal contamination or shallow wells near sources.
  • Microbial activity: Conversion between ammonia, nitrite, and nitrate in low-oxygen conditions.
  • Disinfection changes: Loss of disinfectant residual, stagnant plumbing, or biofilm growth.

When to test

  • At least annually for private wells, often alongside nitrate.
  • After floods/heavy rains, droughts, or septic repairs.
  • Any time you see taste/odor/cloudiness changes or have a positive coliform result.

How we test

HealthWaterLab uses a laboratory colorimetric Griess reaction method with low-level detection and quality controls. Because nitrite can change quickly, we recommend prompt delivery and—if elevated—a confirmation sample.

How to collect a good sample

  • Use the kitchen cold-water tap (primary drinking tap).
  • Remove aerators if instructed; run water several minutes to flush.
  • Fill to the marked line without touching the inside of the bottle or cap.
  • Keep cold and deliver to the lab promptly.

How to read your result

  • Not detected / very low: Maintain annual testing and good well hygiene.
  • Near the limit: Confirm with a second sample and consider treating drinking water as a precaution—especially for infants.
  • Elevated: Treat drinking/cooking water and investigate recent contamination, disinfection loss, or septic issues.

If nitrite is elevated: practical next steps

  • Point-of-use reverse osmosis (RO): Under-sink RO reduces nitrite for drinking/cooking.
  • Address the source: Inspect septic setback/condition, protect the wellhead from runoff, and restore disinfectant residual if used.
  • Retest: Verify treated water and recheck the raw tap after corrections—nitrite can change week to week.

FAQ

Can I taste or smell nitrite?

No—nitrite has no taste or odor. Only a lab test can confirm levels.

Does boiling remove nitrite?

No. Boiling concentrates nitrite. Use RO at the kitchen tap or systems certified for nitrite/nitrate reduction.

How is nitrite different from nitrate?

Nitrite (NO2−) is typically more reactive and indicates recent contamination or active microbial processes; nitrate (NO3−) is usually more stable. Many labs test both together.

Should I also test for bacteria?

Yes. If nitrite is elevated—or if you’ve had flooding or septic concerns—test for total coliform and E. coli to check for microbial pathways.

What is reverse osmosis (RO)?

Reverse osmosis is an under-sink drinking water system that pushes water through a very fine semi-permeable membrane. The membrane rejects many dissolved contaminants (like arsenic, nitrate/nitrite, lead, copper, and salts), producing low-TDS water for cooking and drinking.

How it works: Pre-filters remove sediment and chlorine → the RO membrane removes dissolved ions → an optional carbon “polishing” filter improves taste → treated water is stored in a small tank and dispensed at a dedicated faucet.

Good to know: RO is point-of-use (kitchen sink), not whole-home; filters/membrane need periodic replacement; some water is sent to drain during operation. If you prefer a little mineral taste, a small remineralization cartridge can be added.

Do pitcher or fridge filters remove nitrite?

Standard carbon filters do not reliably reduce nitrite. Choose RO or a system specifically certified for nitrite/nitrate reduction.

Is RO water recommended for infant formula?

Yes—where nitrite/nitrate are elevated or uncertain, use RO water for mixing formula and verify performance with a follow-up test.

My result changed quickly—why?

Nitrite responds to weather, flow, oxygen, and microbial activity. Levels can rise after storms or plumbing stagnation and drop after disinfection and flushing.

Ready to test? Order a nitrite (and nitrate) kit with step-by-step sampling instructions at HealthWaterLab.com.