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 provides monthly data based on our routine testing for bacteria and other contaminants in the City’s Water Distribution System.
The City is required to collect a minimum number of 360 water samples per month, tested for bacteria or other contaminants, to meet the regulatory requirements stated in the Revised Total Coliform Rule (RTCR) of the Safe Drinking Water Act.
Download: RTCR Reference Guide
Each month, the City routinely collects more than the required minimum number of 360 samples to ensure that our water distribution system is monitored correctly and that you are protected from contaminants that could pose health risks.
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.
Monthly routine test results
Understanding the data in the charts
The monthly charts recap weekly test results for bacteriological analysis of the City of Baltimore’s Water Distribution System.
Each of the numbered location IDs represents a testing site in the water distribution system. These locations are part of the Bacteriological Sampling Plan submitted to and approved by the Maryland Department of the Environment (MDE).
Pass: Indicates that a site has met the compliance requirements of the Revised Total Coliform Rule (RTCR).
Fail: Indicates that a site is not in compliance with the RTCR and a violation or level assessment according to the rule has been applied.
Current year: 2023
May 2023
April 2023
March 2023
February 2023
January 2023
2022
December 2022
November 2022
October 2022
September 2022