The heavy rain over the past 36 hours has led the Napier City Council to issue a "we need your help" request of the public.
"We have had a bit of pressure on the wastewater system and you get that when you get very heavy rain - it infiltrates into the network," Napier City Council chief executive Wayne Jack.
He said it had happened at other times of extreme rain and put pressure on the wastewater pumping systems as rainwater added to the volumes.
The council is asking Napier people to try and cut back on flushing, when possible, take short showers and run short washing cycles - for the next 24 hours so the systems could be lowered.
Mr Jack said it was not a major issue however and the city's pumping network had been coping.