Over 1,000 families in Lewis have been told their water is now safe to drink.
Tests on tap water earlier this week showed "unusual microbiology results" said Scottish Water.
Some 250 properties in Uig and 1,000 properties in North and South Lochs, Kinloch and Achmore areas were told to boil water before drinking or cooking as a precaution.
The boil water notices were imposed on the advice of the NHS Western Isles.
Scottish Water said the notices "have now been lifted and customers can use their tap water normally."
The company thanked the affected customers for their "patience and understanding over the past few days.
"Our staff on the Isle of Lewis have worked round the clock to make sure this problem has been resolved as quickly as possible."
Water supplies back to normal
26 September 2015