Hello everyone,
In the Fall 2013 issue of Aqua Talk we ran a brief article regarding the history of disinfection waivers in Colorado and where we were planning to go in the future. We thought it would be a good time now to provide an update.
In 1955 the State Board of Health recognized the tremendous risk reduction from waterborne disease that results from disinfecting drinking water, and adopted a resolution recommending that all drinking water supplied to the public contain at least 0.1 parts per million of free available chlorine. In 1967 the State Board of Health required disinfection of all drinking water unless that requirement was specifically waived by the Colorado Department of Public Health and Environment based on evidence that the drinking water was free of contamination.
Over the years from 1967 to about 2000, approximately 126 disinfection waivers were granted across the state including 62 community water systems serving 60,695 people. The department lacked a systematic process for reviewing the status of these waivers on a periodic basis. The department began to review the status of disinfection waivers in about 2007, which was before the 2008 Alamosa waterborne disease outbreak. We found that many of these systems had already begun to disinfect their drinking water.
In 2010, the Water Quality Control Commission banned new disinfection waivers and imposed more appropriate requirements on systems with disinfection waivers if they wished to retain them. After that, the division began systematically reviewing all the disinfection waivers in the state to make sure that they complied with the requirements and working with systems to get disinfection installed if their disinfection waiver was withdrawn. We continued implementing this rule, and systems that struggled with bacterial contamination had their waivers withdrawn. We also started to periodically review the waivers every year. By late 2010, the number of disinfection waivers fell to less than 40 public water systems.
From late 2010 through about 2013, the division implemented the new requirements regarding disinfection waivers and many systems chose to begin disinfecting while several disinfection waivers were withdrawn as well. By late 2013 only about 15 disinfection waivers remained in place. Since then, the division continued to review disinfection waivers and withdraw waivers when circumstances merited, typically when multiple positive total coliform or E. coli events occurred without there being an adequate way to assure that such events would not recur.
As of 2023, only two (2) of the approximately 2,075 public drinking water systems in Colorado have disinfection waivers, and they are both at community water systems. The systems are the Towns of Ward in Boulder county serving about 230 people and Sanford in Conejos county serving about 850 people. Without further regulatory changes, those systems will retain their waivers as long as they continue to meet the regulatory requirements. We review the status of disinfection waivers annually, whenever there are total coliform rule violations or positive bacterial tests, and during sanitary surveys. The graph below displays the history of disinfection waivers in Colorado from the high point of 2007 to 2023.
➽ Ron Falco, P.E. Safe Drinking Water Program Manager
➽ Bryan Pilson, Technical and Regulatory Implementation and Coordination Unit manager
