What is calculated over the previous 12 months to determine compliance values for TTHM and HAA5 under the Stage 1 DBPR?

What is calculated over the previous 12 months to determine compliance values for TTHM and HAA5 under the Stage 1 DBPR?

• A. Cumulative monthly average
• B. Running annual average
• C. Quarterly average
• D. 12-month rolling average

Answer: (B)

The correct answer is based on the definition and application of the "running annual average." In the context of Total Trihalomethanes (TTHM) and Haloacetic Acids (HAA5) compliance under the Stage 1 Disinfectants and Disinfection Byproducts Rule (DBPR), the running annual average is crucial. This average is calculated by taking the average of the monitoring data for the previous 12 months continuously. Each new month’s data is added to the average, while the oldest month’s data is dropped out. This method ensures that the compliance value reflects recent trends in water quality, allowing for ongoing assessment of whether the water supplier is meeting health standards for these disinfection byproducts. Using a cumulative monthly average, quarterly average, or 12-month rolling average are different approaches that do not align with how compliance values for TTHM and HAA5 are defined under the DBPR regulations. The running annual average specifically captures the most recent data and provides a dynamic view of compliance status in real-time, as opposed to fixed periods or static calculations.

The correct answer is based on the definition and application of the "running annual average." In the context of Total Trihalomethanes (TTHM) and Haloacetic Acids (HAA5) compliance under the Stage 1 Disinfectants and Disinfection Byproducts Rule (DBPR), the running annual average is crucial.

This average is calculated by taking the average of the monitoring data for the previous 12 months continuously. Each new month’s data is added to the average, while the oldest month’s data is dropped out. This method ensures that the compliance value reflects recent trends in water quality, allowing for ongoing assessment of whether the water supplier is meeting health standards for these disinfection byproducts.

Using a cumulative monthly average, quarterly average, or 12-month rolling average are different approaches that do not align with how compliance values for TTHM and HAA5 are defined under the DBPR regulations. The running annual average specifically captures the most recent data and provides a dynamic view of compliance status in real-time, as opposed to fixed periods or static calculations.