Proactive Leak Detection Program Saves Water, Lowers Repair Costs on Critical Pipelines

Leaks are a major challenge for water managers around the world. Addressing water loss is a national priority in Italy where 38 percent of water is lost on average from distribution networks, according to the federation of Italian utilities called Utilitalia.

A leak detection program in Italy’s Campania Region offers a model for water recovery and improving network management. The preventive leak detection program, started in 2019, has also lowered pipeline repair costs and minimized inconvenience to the public.

Municipal pipeline owner Acquedotto Campano launched the program in partnership with the hydraulic engineering company Ena Sud. They are inspecting the transmission mains that supply water to about 2.5 million people across 100 communities, including Naples in southwestern Italy.

The backbone of the Campania waterworks includes four transmission pipelines spanning about 60 miles (100 km). These pipelines are comprised of steel and concrete pipes, ranging in diameter from 28 to 54 in. (700 to 1,350 mm). Most of the network was constructed during the middle of the 20th century, and some leaks are inevitable over this length of service.

Leaks on transmission mains can result in large volumes of water lost, and they can lead to pipe breaks that threaten public safety. Urbanization along the pipelines over the last 50 years has heightened the risk to people and property. For example, several years ago in Caivano, Italy, water leaking from a transmission main invaded the cellars of adjacent buildings resulting in a costly, disruptive repair. Due to the amount of water in the ground, the utility had to build a containment structure to protect the buildings while repairing the pipeline.

With a proactive leak detection program, Acquedotto Campano can locate leaks and intervene before the signs of a leak become visible.

At the start of the program, Ena Sud conducted a thorough survey of the network and monitored pipeline hydraulics to determine the most appropriate leak detection solution. Accurately locating leaks in a far-reaching network like the Campania waterworks is no easy task. Additionally, inspecting transmission mains for leaks is complex due to their large size, flow rate, and depth of cover, which ranges from 10 to 23 ft (3 to 7 m) across the region. These factors precluded the use of external leak detection methods, such as ground microphones.

Due to the critical nature of the transmission mains, it was necessary that they remain in service throughout the inspections. Accurate leak location was also vital to minimize the cost and disruption of repair work in an urban environment.

For these reasons, inline leak detection tools have been a powerful ally for Acquedotto Campano. These tools enable quick, precise results on large-diameter pipes, without public inconvenience. Ena Sud partnered with Pure Technologies, a Xylem brand, to use two inline leak and gas pocket detection tools — the free-swimming SmartBall platform and tethered Sahara platform. Both tools are also helping to confirm pipeline alignment with utility records, where needed.

Inspecting the pipelines between Procida and Ischia, Italy with Xylem’s Sahara platform.

Inspections began in late 2019 on twin steel submarine pipelines that supply the small islands of Procida and Ischia. Measured water loss on one of the pipelines was about 13 gallons per second (50 L/s) — enough to provide a daily supply of water to a third of Ischia’s residents. However, Acquedotto Campano was unable to locate the source of water loss using traditional acoustic correlators or underwater divers. To avoid wasting water, the utility had taken the pipeline out of service. Using inline leak detection, the team identified a huge leak where the underwater pipeline was deepest and covered with sand. Ena Sud quickly deployed divers to fix the leak. Acquedotto Campano can now provide a reliable supply of water to the islands during the busy summer tourism season when the population more than triples.

To date, the team has inspected more than 55 miles (90 km) of pipeline with SmartBall and Sahara. The tools have detected just more than 120 leaks, most of which are small to medium in size. Most leaks on the inspected steel pipes are the result of localized corrosion while leaks on the concrete pipes have occurred primarily at the joints. The tools identified leaks at about one percent of concrete pipe joints.
In addition to leak detection, the Sahara platform captures video inside the pipeline so that the assessment team can identify visual defects in real time. This proved useful during an inspection where the tool’s camera revealed a 560-ft (170-m) section of steel pipeline with severe liner deterioration.
Inline leak detection has provided Acquedotto Campano with a better understanding of its transmission network. They are now making data-driven renewal decisions rather than periodically replacing extensive sections of pipeline.

The utility and Ena Sud have already completed close to 100 targeted repairs, and they are planning selective pipe replacements. Out of the interventions to date, there have been only two where the actual and detected leak locations deviated slightly, and the excavation area had to be enlarged. This precision has significantly reduced the cost of pipe repairs even in the most complex urban areas. Timely, targeted repairs also reduce inconvenience to the broader community.

The program has already recovered large volumes of water, conserving the region’s valuable water resources and reducing energy demand. By proactively identifying leaks, Acquedotto Campano is also protecting the safety of the public and the region’s infrastructure.

Ferdinando Smorra, technical director at Acquedotto Campano. Dario Longobardi is CEO at Ena Sud. Gianpiero Lazzaro is sales team leader at Xylem.