第一阶段消毒剂/消毒副产品（D/DBP）规则延续了DBP之前的监测频率和位置要求，并对五种卤乙酸（HAA5）进行了合规性监测。该规则允许在选择采样位置时具有一定的灵活性。在复杂系统中，根据与处理设施的相对距离选择HAA5监测位置，如佛蒙特州北部调查的系统（70平方英里区域内有16个储罐和12个主要压力区），可能会掩盖导致HAA5结果高度变化的情况。在不了解高度可变HAA5结果的存在和原因的情况下实施治疗过程或系统操作变更可能会影响依从性策略。 在这项研究中，使用HAA5数据、储罐液位趋势和其他操作记录来识别和理解在各个采样位置导致HAA5显著变化的操作条件。包括8个参考文献、表格、图表。

The Stage 1 Disinfectants/Disinfection Byproduct (D/DBP) Rule continuesthe previous monitoring frequency and location requirements for DBPs and institutes compliance monitoring for five haloacetic acids (HAA5s). This rule allows some flexibility in selecting sampling locations. Selecting HAA5 monitoring locations based upon relative distance from the treatment facility in complex systems such as the system surveyed in north Vermont (16 storage tanks and12 major pressure zones in a 70 square mile area) may mask situations that cause highly variable HAA5results. Implementing treatment process or system operational changes without understanding the existence and cause of highly variable HAA5 results may affect compliance strategies. In this study, HAA5 data, storage tank level trends, and other operational records were used to identify and understand the operational conditions causing significant HAA5 variation at individual sampling locations. Includes 8 references, table, figures.