IMPORTANT CLIP Information: Nitrate/Nitrite/Nitrate-Nitrite

IMPORTANT CLIP Information: Nitrate / Nitrite / Nitrate-Nitrite

Dear Drinking Water Laboratory –

If you have accreditation by the California Environmental Laboratory Accreditation Program (ELAP) to perform analytical methods under the Field of Accreditation (FOA) Table 102, titled Inorganic Chemistry of Drinking Water, for Nitrate and Nitrite analyses, please read the following important message.

The Division of Drinking Water (DDW) is concurrently sending communication to all Public Water Systems (PWS) to provide clarification on the monitoring and reporting requirements for Nitrate-Nitrite (analyte code 1038), Nitrate (analyte code 1040), and Nitrite (analyte code 1041).

What is being clarified:

1. When reporting a calculated Nitrate-Nitrite value, the value must be based on component analyses of Nitrate and Nitrite from the same sample or samples collected at the same time and location to ensure accuracy and consistency.

2. When reporting a calculated Nitrate value, the value must be based on component analyses of Nitrate-Nitrite and Nitrite from the same sample or samples collected at the same time and location to ensure accuracy and consistency.

3. When reporting a calculated value into CLIP, the result must be paired with the “CALC” method (scenarios below).

4. Important: When reporting a calculated value, the calculated value and all component analysis results used in the calculation must be reported to CLIP under the same sample ID and within the same submission (i.e., within the same EDD-Electronic Data Deliverable). If the trio of analytes are split between multiple CLIP submittals, all subsequent submittals will be rejected. This will lead to delays in having the data electronically reported as well as the need to resubmit data to CLIP.

Background:

All public water systems must comply with the maximum contaminant level (MCL) established for Nitrate-Nitrite (sum as nitrogen) as set forth in California Code of Regulations, title 22, section 64431. To accurately calculate values to achieve regulatory compliance, Nitrate-Nitrite, Nitrate, and Nitrite must be sampled concurrently at least once every three years. The frequency of monitoring for each individual analyte depends on the analytical results, which may require monitoring more frequently than once every three years. When calculated values are reported for Nitrate-Nitrite or Nitrate, the result must be based on relevant component analysis results from the same sample or samples collected at the same time and location (i.e. a single sample event).

Scenario 1: Calculated Nitrate-Nitrite with addition (not method specific)

Analyte Code	Analyte	Method	Result
1040	Nitrate (as nitrogen)	EPA 300.0	Analyzed result
1041	Nitrite (as nitrogen)	EPA 300.0	Analyzed result
1038	Nitrate-Nitrite	Calc (calculated)	(Nitrate result) + (Nitrite result)

Scenario 2: Calculated Nitrate with subtraction (not method specific)

Analyte Code	Analyte	Method	Result
1040	Nitrate (as nitrogen)	Calc (calculated)	(Nitrate-Nitrite result) – (Nitrite result)
1041	Nitrite (as nitrogen)	EPA 353.2	Analyzed result
1038	Nitrate-Nitrite	EPA 353.2	Analyzed result

Important: 

• When reporting a calculated value, the calculated value and all component analysis results used in the calculation must be reported to CLIP under the same sample ID and within the same submission (i.e., within the same EDD-Electronic Data Deliverable). If the trio of analytes are split between multiple CLIP submittals, all subsequent submittals will be rejected. This will lead to delays in having the data electronically reported as well as the need to resubmit data to CLIP.

Please note, the CLIP technical documentation will be updated to reflect these changes.

[https://download.earthsoft.com/CASWRCB/CASWRCB_DDW_Technical_Documentation.pdf].

For questions or concerns, contact us at DDW-CLIP@waterboards.ca.gov

Thank you,

CLIP Team

Division of Drinking Water | State Water Resources Control Board