The health department originally said E.coli was discovered last month during routine tests. The department ordered 5,000 customers in Des Moines and Normandy Park to boil the water or drink bottled, and also ordered 39 restaurants in the region to close during the advisory.
Now a supervisor from the water district says the water was probably clean all along, but sloppy work by the sampler led to the contamination scare.
On Wednesday evening, the supervisor said he fired the worker who ran the test. He later changed his mind and said the worker's employment status is "under review."
James Ha owns the New Tokyo Teriyaki restaurant in Des Moines. He said he lost at least $3,000 during the forced closure, and he said he knows of other restaurant owners who lost much more.
"I'm very angry, and I'm not alone," Ha said.
The water district supervisor said out of the six samples originally taken, one came back positive for E. coli. Follow-up tests again showed contamination, but now the supervisor believes the tester caused the problems by using improperly disinfected equipment.
"The mistake, gosh, it's such a dumb mistake," Ha said. "It just did not work out well for anyone of us."
Resident Bill Cox said if it turns out that the water district worker was to blame, he should be punished.
"If he did something that caused that, then the answer would be yes. Something should be done," Cox said.
Many of the business owners are now filing claims with the city, hoping the water district's insurance company will cover their losses.