The situation highlighted the power of social media. LLSWD said that normal flow is about 800,00 gallons, however, when a call to action was issued on its Facebook page for users to flush cold water into their tubs, flow increased to 1.6 million gallons.
Liberty Lake Sewer and Water District believe last week’s contamination was likely caused by one of three things:
- A cross-connection with one of the commercial customers
- Inadequate backflow control during sprinkler blowouts
- An illicit connection to a fire hydrant
Liberty Lake runs an unchlorinated water system. One option for fixing the contamination would have been to chlorinate the system and wait 48 hours. The city and its customers have expressed wanting to retain an unchlorinated system.
Because of this, all the water had to be flushed out of the system, sit for 24 hours and then take a sample to test. If that passes, another test is taken 24 hours later, and if that passes the system is clear.
The second contamination was total coliform, which is environmentally based, as opposed to fecal coliform. Coliform requires flushing and testing, not a boil order. Four rounds of clear testing were performed and nothing was found leading LLSWD to believe the initial reading was a false positive.
Liberty Lake City Council – December 3, 2019 Meeting / Public Hearing