What are the monitoring requirements for nitrates?
All public water systems are required to monitor for nitrates at each entry-point to the distribution system. However, the frequency of monitoring varies based on source water type and the level of nitrate and nitrite observed in past samples. Required routine monitoring is annual for ground water sources (or quarterly if a sample exceeds half the MCL) and quarterly for surface water sources (or annual if 4 consecutive quarterly results for the system are less than half of the MCL).
