Kauai county officials are advising the public to avoid contact with some stream waters in Lihue.
County wastewaters crews worked to unclog and stop the sewage overflow at a manhole on the mauka side of Kapaia Bridge Tuesday.
Some of that sewage has affected the Kapaia stream from the highway bridge to Hanama'ulu Bay.
The county estimates that at least 18,000 gallons of raw sewage was spilled in the incident.
Signs will be posted at Hanama'ulu Bay and other affected areas that are accessible to the public.
Officials say the sewer main obstruction occurred after an accumulation of grease and other debris normally found in the sewer system.