An estimated 160,000 gallons of raw sewage overflowed into Seneca Creek (in the Germantown area). The Gazette reports that a loss of power to the Seneca Wastewater Treatment Plant (off Great Seneca Highway) caused the overflow.
People should stay out of the creek.
The Washington Suburban Sanitary Commission terms this mishap a Sanitary Sewer Overflow (SSO). The WSSC doesn’t explain how this accidental discharge is sanitary. If it was sanitary, I think your children should be able to play in the creek.