Both companies are, however, in advanced discussions and were trying to resolve some final issues before a definitive deal could be signed, Hyflux said in a statement to the Singapore Exchange late on Wednesday.
At the start of the week, Utico said a deal had been reached without disclosing financial details.
Hyflux, which is under a court-supervised restructuring process, was once considered a national champion running a strategically important water source for the city-state.
Utico did not respond to a request for comment outside regular business hours.
(Reporting by Nikhil Kurian Nainan in Bengaluru; Editing by Shailesh Kuber)