Coliform Bacteria Level 2 Assessment

Public Water Suppliers conduct a level 2 assessment to determine if there are defects in their system causing coliform bacteria.

Level 2 Assessment Overview

The Revised Total Coliform Rule (RTCR) requires all public water supply systems (PWSs) to complete a Level 2 Assessment in response to the triggers identified in 310 CMR 22.05(4)(a)2.  The purpose of the Level 2 Assessment is to identify the possible presence of sanitary defects and defects in distribution system coliform monitoring practices.  This evaluation provides a more detailed examination of the PWS than a Level 1 Assessment. 

A sanitary defect is a defect that could provide a pathway of entry for microbial contamination into the distribution system or that is indicative of a failure or imminent failure in a barrier that is already in place.  If a sanitary defect is identified during the assessment, the assessor must describe the sanitary defect, what corrective actions were completed, and a proposed timetable for corrective actions not yet completed

Level 2 Assessments must be submitted to MassDEP within 30 days of the trigger date identified in the “General Information” section of Instructions for Level 2 Assessment . If upon review, MassDEP determines that the assessment is insufficient, MassDEP will send the PWS written notification.  The system is required to consult with MassDEP within 14 days of receiving notification of an insufficient assessment.

The Instructions for Level 2 Assessment document is to be used as a companion to the Coliform Bacteria Level 2 Assessment Form. It contains information necessary for completion of the form.  For more instructions on performing Level 2 Assessments, assessors are strongly recommended to read the EPA Revised Total Coliform Rule Assessments and Corrective Actions Guidance Manual.

If the PWS has detected a fecal indicator in the source water, it may also be required to perform corrective actions and/or develop a corrective action plan under the Ground Water Rule (310 CMR 22.26).  In that situation, the Level 2 Assessment Form may be used to report corrective actions taken to comply with the Ground Water Rule, and the Corrective Action Schedule portion of the form may be used to comply with both the Corrective Action Plan requirements of the Ground Water Rule and the RTCR.

Who May Perform a Level 2 Assessment?

Unless the PWS is notified that MassDEP will conduct the assessment, the Level 2 Assessment must be conducted by a party approved by MassDEP.  The PWS shall consult with MassDEP regarding the identification of the Lead Assessor at the time of notification that the PWS has triggered a Level 2 Assessment.  MassDEP considers the following individuals qualified to serve as lead assessor: a person holding a full Drinking Water Operators license of a grade (treatment or distribution) equal to or higher than that of the PWS qualified to be the Lead Assessor, or a technical assistance provider under contract with the state.  Other individuals may be approved to perform the role of Lead Assessor at the discretion of MassDEP.  Refer to the document Criteria for Approval of Individuals Allowed to Conduct RTCR Level 2 Assessments.

General Comments on Format and Completion

The Level 2 Assessment Form is a fill-in-the blank document that meets the requirements of the Level 2 Assessment Report.  The form must be completed without changes.  The fields in the document will expand as necessary.  However, if you have an extensive explanation or need additional space, extra pages can be attached.

The form is designed so that additional pages may be completed as needed for a PWS with multiple sources or other components.  When all required pages of the form are complete, the pages should be numbered consecutively for the entire document.  Refer to the document Instructions for Level 2 Assessment for complete instructions.


All complete Level 2 Assessment Forms must be signed by the Lead Assessor (the MassDEP approved party identified on Page 1 of the form). 

In the event that the Level 2 Assessment Form contains a Corrective Action Schedule, the owner or responsible party for the PWS must also sign the form, certifying the timelines in the schedule.

Approval/Determination of Sufficiency

Once the completed Level 2 Assessment Form has been submitted to MassDEP, the assessment and corrective actions will be reviewed.  If the assessment is deemed sufficient, the form will be approved and the timelines for any future corrective actions will be enforceable deadlines.

If MassDEP determines that the assessment is not sufficient, the PWS will be notified, and will be required to have a consultation with MassDEP regarding the assessment.  A revised assessment must be submitted within 30 days of the date of consultation.

Follow-Up Actions

Corrective Action Schedules

If you submit a Corrective Action Schedule as part of the assessment, for any corrective actions not completed at the time the Assessment Report is submitted, you must complete the corrective actions by the date specified in the approved Corrective Action Schedule.  It is required that you notify MassDEP in writing when each scheduled corrective action is completed.

At any time during the corrective action phase, you may request a consultation with MassDEP to determine appropriate actions to be taken.  No changes to the approved Correction Action Schedule and timeline may be made without prior approval of MassDEP.

CCR Reporting

For any Level 1 or Level 2 assessment that is triggered for a Community system, a special statement and health effects language must be included in the CCR regarding the assessment(s).  Additional language is also required for any Treatment Technique violations or E. coli MCL violations.  Refer to The Drinking Water Regulations 310 CMR 22.16A(8)(h) for specific requirements.

Emergency Reporting Requirements

In the event that the PWS experiences an emergency as defined in 310 CMR 22.15(9) Emergency Reporting, the PWS will be required to follow all emergency notification requirements as well as submit an Emergency Response Report (After Action Report) within 30 days.  Emergencies that may be identified as part of the assessment process include vandalism, E. coli contamination, or loss of pressure in the distribution system.  Refer to Guidelines for Public Water Systems Appendix O, Handbook for Water Supply Emergencies for more information on emergency reporting requirements.


For questions regarding the Revised Total Coliform Rule requirements please contact the MassDEP Drinking Water Program Boston office, or your MassDEP regional office.

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