North Shore City Council is asking residents in Takapuna, Devonport and East Coast Bays to keep an eye on their water clarity this week.
Watercare Services is carrying out an essential upgrade on two water mains that pass under the harbour bridge from Tuesday until Thursday.
The council says the work may cause water for some people to become discoloured, but it will still be safe to drink.
It says the water colour should clear, if taps and washing machines are left to run for a minute or so.
