Any time a water system has a main break or depressurization event, there are two goals – to always protect the public health and safety and to restore normal water service. These two goals, in the order listed, must always be the focus. In 2016, the Iowa Main Break Guidance was updated to incorporate the changes from revised American Water Works Association (AWWA) Standard C651-14.
Recently, EPA Region 7 advised Iowa DNR staff to require acute (immediate) public notice for water systems with manganese levels above 0.3 mg/L (ppm) due to recent health studies. In response, a committee was formed to update the Iowa Main Break Guidance. This committee included representatives from the Iowa Section of AWWA, Iowa Association of Water Agencies, Iowa Rural Water Association, Iowa Association of Municipal Utilities, and Iowa DNR Water Supply Operations, Water Supply Engineering, and Field Offices.
Revisions to the Iowa Main Break and Depressurization Guidance were completed earlier this month. The major revisions include the use of bottled water rather than boil water advisories for systems with elevated or unknown manganese levels, and advice for customers to not drink or cook with colored water. This document has been approved and is now being implemented. A copy of it is available on the Iowa DNR Public Notice webpage. Look for the “Main Break and Depressurization Guidance” section in the lower right side of the webpage.
To be prepared, systems are encouraged to sample for manganese at their Source Entry Point(s) so they know the manganese levels in their system. If the manganese levels are unknown and the system has an incident that necessitates an advisory, the advisory will be a bottled water advisory. Systems with known low levels of manganese (less than 0.22 mg/L), nitrate (less than 7 mg/L as N), and nitrite (less than 0.7 mg/L as N) will issue a boil water advisory. It is very important for operators to know the levels of these three contaminants in their systems when they call the DNR for assistance, especially if they call after hours.
The guidance includes specific information about the four categories of main breaks, guidance about repair of each, when boil or bottled water advisories are recommended or required, and specific information when bacterial sampling is recommended or required following depressurization events. Included in the guidance are templates for a main break log, a communication plan including boil and bottled water advisory templates, and a one-page summary of the procedures for each main break type.
Watch for training opportunities about the guidance and contact your Iowa DNR Field Office with specific questions.