Significant spike in sewer blockages amid prolonged dry

SA Water is urging South Australians to be vigilant with what goes down their plumbing after recording a significant spike in sewer main blockages over the year – driven by increased tree root intrusion from dry conditions.

In 2024-25, there were 5,132 sewer main blockages reported across the state, up from 4,383 compared to the previous financial year.

The most common cause remains tree roots, responsible for nearly two-thirds (3,275) of all pipe blockages recorded in 2024-25 – a notable increase from 2,352 the year prior.

SA Water’s Senior Manager of Infrastructure, Planning and Strategy Dr Daniel Hoefel said the dry weather has played a significant role in the increase.

“Recent sustained dry conditions have prompted trees to seek moisture from within our sewer network, pushing roots into pipes and causing blockages, and in some case, sewage overflows,” Daniel said.

“This trend is especially visible in suburbs such as Morphett Vale, Flagstaff Hill, Happy Valley, Athelstone and Rostrevor – the worst affected areas for tree root intrusion.

“We encourage our customers to use our online tree planting guide when planting new trees and shrubs on their properties, to ensure selected species that can minimise tree root intrusion on their private pipework or our sewer network.”

Non-flushable items like wet wipes, sanitary pads and tampons also continue to be a concern for SA Water’s sewer crews, with 569 sewer main blockages caused by these materials during the past 12 months.

Suburbs such as Elizabeth North, Hackham West and Morphett Vale were among the worst offenders for wet wipe-related blockages within the utility’s network across this period.

When combined with blockages that occurred at a property’s connection – which increases the risk of an overflow inside the house – this number rises to 1,803 blockages caused by similar non-flushable items.

“This provides a timely reminder for everyone to only flush the four Ps – pee, poo, (toilet) paper and proof the items are flushable,” Daniel said.

“Wet wipes, even some labelled ‘flushable’, do not break down like toilet paper and can easily clog up household pipes and our mains, so it’s important to check the label for proof that the product is certified and safe to flush.”

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