Bobbi Gladstone, Worth County Public Water clerk, said the break happened on Highway C.
The boil advisory will impact customers east of Denver (not within city limits) to Siloam and those south on Highway C in Worth County.
Gladstone said crews are working to repair the broken main now, but the advisory could last until Thursday.
Customers can call Worth County Public Water with questions at (660) 564-4082.
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