The City’s aging water pipe infrastructure has been the primary cause in a rash of recent water main breaks that have crippled various areas of the Los Angeles.

In a recent article, the Los Angeles Times estimates that about one-fifth of the city’s water pipes were installed before 1931 and nearly all will reach the end of their useful lives in the next 15 years. They are responsible for close to half of all water main leaks, and replacing them is a looming, $1-billion problem for the city.

The DWP has a $1.3-billion plan to replace 435 miles of deteriorating pipe in the next 10 years, but difficult questions remain about how the agency will find the money, how much it will inconvenience commuters and whether the utility can ever catch up with its aging infrastructure.

To reach its goal by 2025, the DWP would need to more than double the number of pipe miles it replaces annually and more than triple the average amount it spends on pipe replacement each year. Water officials said the department has already budgeted $78 million for water main replacement in the current fiscal year, a significant increase from its annual average.


6,730 — Miles of pipe in the DWP water main network

435 — Miles of deteriorated water mains that DWP wants to replace, about 6.5% of the network

$1.34 billion — Cost to replace at-risk water mains by 2025

$44 million — Annual average amount DWP has spent on pipe replacement in the last eight fiscal years

$135 million — Annual spending needed to reach 10-year pipe replacement goal


Cast iron pipes dominated the city’s network as the most common type of material used until the 1970s, when steel mains and ductile iron pipes became more common.
The DWP uses letter grades to prioritize water mains for replacement in the city’s 6,730-mile network.