Non-Field Guidance and Technical Assistance

Municipal, Industrial, Commercial and Other Laboratories

The information contained on these pages is meant to provide technical assistance, guidance and tools for meeting the requirements of NC WW/GW Laboratory Certification. On this page you will find guidance documents and technical assistance as well as Approved Procedures for Field Parameters. The following pages contain policieschecklists and other tools pertaining to laboratory operations.

Guidance documents and technical assistance

Guidance documents are meant to provide detailed information for meeting policy or regulatory requirements.

Document Revision Date Description
 MDL Calculator *new* 05/09/2019 Spreadsheet for laboratories to use to calculate initial and/or on-going MDL.
 MDL Presentation *new* 04/27/2018 Lab Tech Day 2018 presentation about the new MDL procedure.
Standard Methods QC Requirements Chart 09/19/2017 Spreadsheet outlining QC requirements for Standard Methods methods per the QC chapters (e.g., 2020, 3020, 4020, etc.)
Fecal Coliform (MF) Colony Confirmation Video 02/13/2018 This video provides a visual example of most elements involved in performing the monthly fecal coliform colony verification required for laboratories certified for Standard Methods 9222D. Please use this in conjunction with the technical assistance document linked below to assure all requirements are met and to further explain the process.
Fecal MF Colony Verification Technical Assistance  02/21/2018 Assistance in performing the required monthly colony verification for Fecal Coliform (Membrane Filter)
Fecal MF Colony Verification Example Benchsheet   11/3/2017 Example benchsheet to use when performing the colony verification and adjusting colony counts
Procedure for Testing Consumable Materials for Biological Testing 02/07/2017 A procedure for verifying the efficacy of new lots of consumable materials used for biological testing 
Fecal Coliform Reporting Guidelines  04/08/2016 Guidelines for enumerating and reporting fecal coliform results
MPN Table with 95% Confidence Ranges N/A Table provided by IDEXX with MPN results and 95% confidence ranges using the Quanti-Tray/2000 which can be used to evaluate duplicate precision. 
LDO Daily Calibration Verification Procedure  06/16/2009 A procedure for verifying the calibration of Luminescence Dissolved Oxygen (LDO) meters by back calculation with solubility table
Calibration of Pipettors  07/30/2009 An example procedure for the gravimetric verification of mechanical liquid dispensing devices 
Matrix Spiking Technical Assistance Document  02/23/2018 A document describing appropriate matrix spiking frequencies and practices 
Memo to Permittees Regarding TRC 50 µg/L Compliance Level   05/01/2008 A memo from the NC DWQ Point Source Branch describing the 50 ppb compliance level for Total Residual Chlorine (TRC)
Corrective Action Response to Audit Findings Form 06/07/2017 A form describing the corrective action response and documentation needed for labs to address Findings from audits. There is an example of a lab's response after the report has been received and also for a Finding that is corrected before the report has been written.
Ammonia/Fluoride Distillation Technical Assistance Document


*newly updated*

A document describing the background and implementation of Ammonia and Fluoride distillation study requirements in accordance with 40 CFR Part 136.3, Table IB, footnote 6.

Approved Procedures for the Analysis of Field Parameters

These procedures are intended to provide the approved procedures and requirements for measurement of field parameters. You may refer to the approved method reference, instrument manufacturer's manual or other resources for additional information. 

Field Parameter Revision Date
Total Residual Chlorine  February 2019
pH  November 2017
Dissolved Oxygen  December 2017
Temperature  January 2018
Specific Conductance  January 2018
Settleable Residue  January 2018


Link to National Pollution Discharge Elimination System (NPDES) Permitting Guidance, Directions for Completing a Discharge Monitoring Report (DMR) and Calculating Data for DMR reporting. Look under Compliance Forms. You can also find a link to the list of Significant Figures and Their Use on DMRs document on that page.

The following documents published by EPA are good sources for general guidance in performing internal audits of NPDES permitted facilities. NPDES Compliance Inspection Manual (Interim revised version from January 2017); NPDES Compliance Monitoring Inspector Training (August 1990); Handbook for Analytical Quality Control in Water and Wastewater Laboratories (March 1979)

Link to USEPA STORET Legacy Data Center. Questions can be directed to the STORET Help Desk at


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