Residents of two homes were so badly affected, they've had to spend the night away from their wastewater-logged properties.
Many Aucklanders will also be heading to the beach for a scorcher public holiday today.
It is expected to reach a high of 29C.
Watercare acting chief operations officer Mark Bourne said tomorrow morning was likely to be the earliest the beach would be officially open.
He said the normal advice was to wait 48 hours after an overflow - but that decision was ultimately up to Auckland Council experts.
The pipe has been fixed but there was still plenty of work to do. he said.
Workers were back decontaminating homes this morning.
A local group said the council needed to send a stronger message on contaminated water.
Milford Residents Association co-chair Norma Bott said the warnings didn't relay the gravity of the situation.
She said there were just two signs on the beach, and none at the entrance to the creek where the contaminated water was flowing from.