There are currently no links to where the nine-year-old who tested positive to COVID in Cowra on the weekend may have caught the virus.
"We're doing a lot of testing obviously with the family and other people connected to the case," Western NSW Chief Executive Scott McLachlan said on Monday.
"We don't have links yet to where they picked it up so we're really cautious that this may not be the case that was triggering the sewage testing.
"This family does not live in Cowra, they live outside of Cowra, so I really urge caution to anyone around Cowra.
"If you've got any symptoms please, most urgently come and get tested.
"Even if you don't have symptoms come forward and get tested.
"If you've been tested in recent days and you develop symptoms please come back and get tested.
"We really want to find where the COVID transmission might be coming from," Mr McLachlan said.