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Update 6/4 Missouri American Water Boil Advisory Lifted
Map of the affected area - A map from Missouri American Water defining the area of the boil advisory.
Posted on Thursday June 04, 2020
The Boil Order has been lifted. Missouri American Water is issuing a precautionary boil advisory related to a broken water main and concurrent low-pressure event for customers in St. Charles County, Mo., including customers in the municipalities of Cottleville, Weldon Spring, unincorporated St. Charles County and O’Fallon, Mo.


  1. A water main break near the post office in downtown Cottleville at Highway N and Chestnut St. led to a water pressure drop in the area, causing the precautionary boil advisory.
  2. The advisory affects approximately 5,600 customers.
  3. Water for these customers will need to be brought to a boil for 3 minutes prior to consumption, until further notice. Tap water is okay for washing, bathing and other non-consumable uses during this period. 
  4. The precautionary boil advisory is required because of regulations regarding water pressure in their system. In this instance, water pressure dropped to a level that requires they issue a precautionary boil advisory.
  5. Boil advisories typically last 24 hours, though they cannot guarantee that timing.
  6. Water quality tests will be run once the main is repaired.
  7. Customers are being notified by their reverse-911 system, and will be notified again when the boil advisory is lifted. Notice will also be posted to social media and the company website.
  8. Customers can visit a new website to enter an address and confirm whether it is within the affected area. The site can be found by visiting the Missouri American Water website at and click on News & Community, then Maps. Then click the on-page image and select Boil Advisory Map. From there, enter an address to search if it is within the affected area. Direct link: