Poop Drones Are Keeping Sewers Running So Humans Don't Have to

On the morning of Christmas Eve 2016, residents of a house in Fraser, Michigan heard a curious pop, pop, popping sound coming from their walls. After initially dismissing it as melting snow falling from the roof, they soon realised the truth: the noise was the result of bricks being squeezed out of place as their home slowly crumpled into a sinkhole.

The house and several nearby were evacuated as authorities assessed the situation and determined its cause: a collapsed sewer interceptor, threatening several homes and a long stretch of Fraser’s busy 15 Mile Road. It was hardly the start to the festive season anyone would wish for.

“This was quite the impact to our system and community,” says Vince Astorino. As Operations Director at the Macomb County Public Works Office, he’s responsible for overseeing the daily operations of the county’s wastewater infrastructure, including some 68 miles of sewer lines. “An 11-foot diameter sewer, approximately 70-feet deep, experienced a failure which drastically reduced wastewater flow. This section of pipe is near the main outlet of our system and approximately 800,000 residents rely on it to convey their wastewater downstream.”

Prompt action from Astorino and his team got bypass systems in place in time to prevent sewage backing up into residents’ homes, and in the end only one building—the house where the popping sound was heard—required demolition. But it was nine months until the offending stretch of pipe, roughly 4000 feet of it, would be fully replaced. The direct cost to taxpayers was around $75 million, not taking into account the added costs to residents and nearby businesses as a result of the disruption.

The key to preventing disasters like this is regular inspection of sewer lines, hunting down any cracks and fissures that, if left unattended, can lead to soil ingress and eventual collapse of the pipe. But sewer pipes can be dark, cramped and filled with pockets of gas, making inspecting large networks using traditional methods (typically a tethered, remotely operated crawler fitted with a camera or even in-person) a slow, costly and often hazardous process.

This is where drones come in. Designed and engineered to operate in confined spaces, a new generation of flying robots is being sent into sewers to perform inspections in a safer, more efficient way.

One such drone is the Elios 3, designed and manufactured by Swiss company Flyability and used by major industry players like Veolia. Equipped as standard with a protective cage, impact-resistant exoskeleton, 16,000-lumen lighting rig, 4K camera and LiDAR, it can navigate through dark and dusty pipes while creating a live 3D model of the environment. The modular design means it can also be fitted with specialized payloads like explosive gas sensors or ultrasonic thickness gauges.

Eloise McMinn Mitchell, Communication Manager at Flyability, says that the company is seeing huge sales growth as a result of the Elios 3’s capabilities and efficiency versus in-person human inspections, particularly when it comes to sewers. “To inspect a stretch of sewer underneath a road, you’ll need teams of at least four people and have to divert traffic in multiple locations. With the drone, you just need two people, and nobody has to climb into the sewer, eliminating confined space risks and exposure to hazardous environments.”

As a result, the safety rules surrounding drones are much less rigid than when humans are involved, which McMinn Mitchell says greatly eases the cost of inspections. “There’s an average 40 percent cost reduction compared to traditional methods, and you can inspect 900 meters in a day with the drone compared to 400 meters.”

In May 2024, in a drive to streamline their inspection process, Macomb County adopted a technology-led approach combining a remotely piloted Asio X drone, built by Flyability rival Flybotix, with a software program called SewerAI. The total cost of both was around $100,000. Previously, the county had been spending $1 million on inspections every three years, manually inspecting footage for defects, many of which could be missed due to the poor image quality.

Around 16 inches across and equipped with powerful 40,000-lumen lights, a 4K camera and a cage for protection against collisions, the Asio X can capture crystal clear video of the sewer system while navigating all but the narrowest of pipes. Astorino describes it as a “night and day difference” to the old method.

Unlike some of the latest consumer drones, which fly almost autonomously, the Asio X requires mostly manual control, and in some very unforgiving locations too, as Astorino points out: “It’s dark, air flow can quickly change within a confined space, and managing a flight path above flowing water in a restricted pipe is challenging.” As a result, he leaves flight to the experts: “Our main operator, Captain Zach, is able to fly through some very tricky environments.”

That being said, the inspection process itself is straightforward. “An antenna is lowered into the manhole to provide signal strength from the drone controller to the drone,” Astorino tells WIRED. “The operator will fly the drone from one manhole to the next, recording video through that flight path.” With around 20 minutes of battery life, the Asio X can document around 1,000 feet of pipe in a single flight, capturing not only video but LiDAR and infrared scans, and gas readings as it passes through a section of sewer.

Under the old system, video data would be analyzed in the field, with the camera operator logging defects as they navigated through the pipes. Now, the drone-captured data is sent off to contractors at SewerAI, who run it through their AI-assisted algorithms to identify defects automatically. Astorino tells me it’s been a game-changer, saving his team huge amounts of time and money.

“We performed months of testing against coded video in the field from various contractors against what SewerAI was able to do with the same footage, and every single time SewerAI excelled in what it was able to find and code correctly.” Previously, inspecting a section of sewer pipe might take months, but SewerAI has an agreement to send data analysis back to the county within 10 days; Astorino says it usually does so within 24 hours.

The team have been so impressed with the software package that even in areas where the drone cannot go and more traditional methods of inspection are required—small diameter pipes, for instance—the resulting data is now sent off for analysis rather than being coded in the field. Old data can be quickly reviewed and re-analyzed too, picking up defects the original contractors may have missed at the time. This means repair work can be done where it’s most needed, preventing the sort of worsening conditions that can lead to disastrous and costly incidents like the 2016 sinkhole.

Macomb County has been a pioneer in this field. It’s the first county in Michigan to utilize this combination of drones and AI software for underground infrastructure inspection and has won two in-state awards as a result of its forward thinking. But Vince Astorino tells me he and his team are always on the lookout for new ways to modernize operations. “It’s hard to count out great leaps forward in technology around this space, especially with the great AI race taking place all around us. We’re keeping our options open.”