(TNS) — San Diego, Calif., sharply reduced the number of water main breaks and sewer spills across the city last year, saving ratepayers money and helping many neighborhoods avoid significant disruptions.

City officials credited the decreases to ramped-up maintenance and replacement efforts on water mains, sewer lines and pipes, particularly those made of cast iron.

And to further reduce breaks and spills, San Diego officials say they will soon begin using drones and other monitoring devices to look for early warning signs of potential problems.

"We've focused on replacing our old cast iron water mains and sewer lines to improve neighborhood infrastructure and better protect our environment," Mayor Kevin Faulconer said. "This has led to a significant decline in the frequency of spills and flooding, and that's good news for our neighborhoods."

In 2019, San Diego had the fewest water main breaks in 15 years. The 38 breaks last year was a drop of more than 35 percent from 2018 and far lower than the record 131 breaks recorded in 2010.

The number of sewer spills dropped nearly 25 percent last year, from 50 in 2018 to 38 in 2019. Both totals are far lower than the record 365 spills recorded in 2000.

"New pipelines, monitoring tools and the vigilance of our Public Utilities crews are making a huge difference," said Shauna Lorance, who took over as the city's Public Utilities director last August.

Lorance credited much of the improvement to ongoing efforts to replace old cast iron water mains and replace or reline sewer mains.

Since 2013 San Diego has replaced approximately 220 miles of water mains across the city. The remaining 60 miles of cast iron mains are scheduled over the next few years, with the goal of eliminating all cast iron by 2024.

Since July 2016, more than 170 miles of sewer mains have been replaced or relined. An additional 200 miles are scheduled to be replaced or relined during the next five years.

New water and sewer mains are made of polyvinyl chloride, which is expected to last much longer than pipe materials used in the past, including cast iron.

Lorance also credited improved preventative maintenance work by Public Utilities Department staff. Crews routinely inspect pipelines, valves, pumps and other portions of the water and sewer systems, she said.

"One of the ways to have excellent customer service is to reduce the number of potential breaks and spills that impact people's lives," she said.

The goal is to replace pipes and mains before they break, but to avoid being so proactive that neighborhoods are being dug up for preventative maintenance more often than necessary.

On the new monitoring systems and drones, Lorance said San Diego officials will join other cities on the cutting edge when they start to use them.

"They're on the advanced end of the spectrum," she said.

The monitoring devices will be placed near sewer mains considered high risk for spills, to detect early warning signs of preventable blockages, root intrusion, sediment or debris.

The drones will fly over environmentally sensitive areas and challenging terrain after significant rainstorms to identify potential problems for maintenance crews to resolve.

©2020 The San Diego Union-Tribune. Distributed by Tribune Content Agency, LLC.