Watercare's smart sensors have prevented its first sewage overflow in South Auckland

The $12 million project uses AI to track sewer levels and can detect irregularities in Auckland's network such as a sudden rise in levels.

Just a few days other it was installed, a sensor in Lovegrove Crescent in Otara detected a blockage 40 metres away.

That meant crews could respond immediately, lifting the manhole lid and flushing the blockage.

Watercare says without the sensor they would have been responding to a sewage overflow instead of preventing one.