Routine Testing Results

Overview

The City of Baltimore is proud to serve approximately 1.8 million people with award-winning quality drinking water each and every day. As part of this service, the City is now providing monthly data based on the bacteriological test results for the City’s Water Distribution System. The City is required to routinely collect a minimum number of 360 bacteriological samples per month to meet the regulatory requirements stated in the Revised Total Coliform Rule (RTCR) of the Safe Drinking Water Act. The City routinely exceeds the required minimum number of 360 samples monthly to ensure that the water distribution system is monitored correctly and that you, the consumers, are protected from contaminants that could pose a health risk.

Regulatory Requirements

When contaminants are detected within the distribution system resulting in a positive test for coliforms and/or E. coli, we are required to verify the original results by sampling the original location along with an upstream and downstream sample and report such findings to the Maryland Department of the Environment (MDE) within 24 hours of the test result. If the total number of total coliform-positive samples collected for a month exceeds 5% of the total number of samples collected in a month, the system would then be found non-compliant with the rule and would be in a Maximum Contaminant Level (MCL) violation for that month. Suppose one E. coli-positive sample is detected within the system. In that case, the E. coli detection will result in an E. coli MCL violation, and the system will be found non-compliant for that month. DPW must also report this information in the Annual Water Quality Report for the year it took place.

Information Presented

The information in the chart below summarizes the test results for the weekly bacteriological analyses of the City of Baltimore’s Water Distribution System for September 2022. Each of the numbered location IDs corresponds to a location on the illustrated map of the distribution system. These locations are part of the Bacteriological Sampling Plan submitted and approved by the Maryland Department of the Environment (MDE). The designation of “pass” indicates that a location has met the compliance requirements of the Revised Total Coliform Rule (RTCR). A designation of “fail” indicates that a site is not in compliance with the rule and resulted in a violation or level assessment according to the rule.

RTCR Reference Guide