These data are from the Environmental Monitoring and Mapping System (EM&MS), an Oracle database maintained by the Massachusetts Water Resources Authority (MWRA) Environmental Quality Department (ENQUAD). These data are collected from a variety of sources which measure the data for a variety of different uses and with different standards for accuracy and precision, and are distributed as is. MWRA cannot ensure that they are appropriate for any particular use. Neither the Commonwealth of Massachusetts, nor any agency to whom MWRA has given data, or from whom MWRA has obtained data, shall be held liable for any reason related to the accuracy or fitness of the provided data.

Data accepted into EM&MS are subjected to further in-house quality assurance procedures which are continually being refined. Data are updated or qualified as new errors are found. These changes are made without notice to prior users of the data. Please contact ENQUAD to ensure that you are using the latest set of data, to learn about the quality assurance procedures, or to inform us of any errors you find in the data.