A wastewater overflow is when sewage flows out from the pipes or manholes where it is usually contained, due to an incident, and into the stormwater system, which then drains into a stream, river or the sea.

Wastewater overflow details are listed below. Information will be updated as soon as possible. If you see signs about polluted water around the city and have further questions, please contact us(external link)

This is a manual process, so there may be delays during busy periods.  Event identification (ID) numbers are not consecutive, due to false alarms, etc. Pollution may take up to two days to completely clear after the discharge has ceased.

2024 overflows

Discharge began Discharge ceased ID Overflow location Receiving waterway Cause
8 July 11am 11 July 4.50pm 519 Cressy Terrace, Lyttelton Lyttelton Harbour Pipe collapse
22 June 4pm 22 June 5pm 518 Wainui Road, Riccarton Avon River Fat blockage
9 June 4.20pm 9 June 6.30pm 515 Hoon Hay Road, Hoon Hay Heathcote River Fat blockage
2 June 7.30pm 2 June 11pm 513 Purau Bay, Diamond Harbour Lyttelton Harbour Root blockage
13 April 6am 15 April 11.30am 482 McCormacks Bay Road, Redcliffs Ihutai Estuary Blockage
17 March 8pm 18 March 3pm 481 Balguerie Stream, Akaroa Akaroa Harbour Broken pipe
6 March 12am 6 March 12.55pm 480 Hollis Avenue, Cashmere Heathcote River Root intrusion
25 February 12.30am 25 February 1.30am 479 270 Sparks Road, Halswell Heathcote River Electrical failure

Past overflows