Beneath Brisbane's streets, a slow-moving crisis is building — and it smells exactly as bad as you'd expect. Wet wipes flushed down household toilets are combining with cooking fats and oils to form massive, foul-smelling blockages known as fatbergs, costing ratepayers nearly $3 million a year to fix and putting serious strain on the city's ageing sewerage network.

David Brooker, Urban Utilities' executive leader of operations and maintenance, oversees a vast infrastructure operation covering more than 20,000 kilometres of pipe, 28 wastewater treatment plants and 348 wastewater pump stations across Brisbane, Ipswich, the Scenic Rim, Somerset and Lockyer Valley council areas. He says wet wipes are among the biggest headaches his teams face — day in, day out.

"You can imagine what it smells like," Brooker said, describing sewage that can sit trapped in a fatberg for days or even weeks at a time.

What Is a Fatberg — and Why Are Wet Wipes to Blame?

A fatberg forms when wet wipes — even those marketed as flushable — fail to break down the way conventional toilet paper does. Unlike standard paper, these wipes remain largely intact after flushing, and when they come into contact with fats and oils washed from kitchen sinks, they bind together into a dense, compacted mass.

"It can clump up in pipes, it clogs up pumps or clogs up our treatment plants," Brooker said.

Fatbergs account for roughly 20 per cent of all blockages in the network. In 2025 alone, the approximately 3,000 blockages recorded across the wastewater system cost close to $3 million to address. A record-breaking example pulled from the network in 2021 weighed in at 500 kilograms.

Brooker said wet wipe use has risen sharply in recent years, with the material now turning up at treatment facilities far more frequently than it did five — let alone ten — years ago. The wipes regularly surface at sites such as the Luggage Point water treatment plant.

A Growing Awareness Campaign — Including a Comic About Fatbergs

Urban Utilities has been running a public education push to alert residents to what should and shouldn't go down the drain. The campaign includes a comic titled Rise of the Fatberg, distributed at the Ekka, designed to make the issue accessible to everyday households.

The advice is straightforward: avoid flushing wet wipes altogether, and rather than pouring cooking fats and oils down the sink, wipe out pans and dispose of the residue in the bin.

The awareness drive comes at a time of heightened scrutiny of Brisbane's water infrastructure, following a series of notable pipe bursts last year and the company having to walk back planned increases to bulk water charges.

Brooker acknowledged that because the infrastructure is buried underground, his teams cannot monitor every section of the network at all times — making prevention all the more important. "What we're really wanting people to be aware of is what they put down their toilet and sink really matters," he said.

Tree Roots, Ageing Pipes and the Road Ahead

While fatbergs grab attention, Brooker identified tree roots as the single greatest ongoing challenge for the network. Roots seeking moisture work their way into pipes — some of which are up to a century old — and Urban Utilities runs a routine program to identify vulnerable sections before problems escalate.

When it comes to upgrades, Brooker said the driving factor is population growth rather than the age of the system itself. Remediation options range from the relatively affordable method of re-lining existing pipes to the considerably more expensive option of duplicating them entirely.

The team operates around the clock — with on-call crews for emergencies, a monitoring centre at the company's Fortitude Valley headquarters, and a broader workforce of engineers and support staff continually working to maintain and improve what is one of south-east Queensland's most critical pieces of hidden infrastructure.

For now, Brooker's message to Brisbane households is simple: think before you flush.