A broken water main in a Westwood neighborhood sent Los Angeles Fire Department crews to the scene just before 10:30 pm on Monday. In the 10400 block of Wilkins Avenue, near Thayer Avenue, a surge of water caused minor flooding and a dangerous sinkhole to open in the middle of the street.

Crews from the LA Department of Water and Power shut off the water before the street could fully collapse. According to investigators, the flood was caused by a break in an 8-inch wide cast iron pipe near the scene. While investigators have yet to declare any specific reason for the ruptured pipe, it is potentially just a simple matter of age and pressure.

No homes were damaged, though 22 residents were left without water on Tuesday morning. Drivers were advised to avoid the area while LADWP crews used heavy equipment to break apart the street. The pipe was expected to be fixed during the day on Tuesday.

Urban sinkholes are such a rare event that no database exists to track how frequently they occur. In cases like this, a sinkhole is a secondary event to the failure of a water main. The flow of water beneath the road washes away soil or soft rocks, forming a cavern beneath it. Eventually, the weight of the road itself tears open the hole, collapsing into the formed cavern. Sinkholes like this are uncommon in Los Angeles, where the ground is usually more resistant to erosion.

Still, there is the potential for sinkholes to occur anywhere that water has been in motion at any point, and can be caused by rain or groundwater flow. Usually, sinkholes occur gradually and give ample warning. In most cases, potential sinkholes will be identified as part of infrastructure maintenance well ahead of time. Sewer inspections beneath the streets can identify erosion, for instance, or road crews will notice cracking and sagging in a road as the earth beneath it begins to buckle.

In sudden events like this, the blame is most likely on infrastructure failure. The power of the broken water main, combined with conditions beneath the road, created a sinkhole where one may not otherwise have occurred. The key to avoiding events like this one is to properly maintain water and road infrastructure.

Media reports have discussed the underinvestment in infrastructure maintenance in Southern California, including LA. Infrastructure spending in Southern California has decreased by more than a third, including a 38% decrease in the investment in drinking water infrastructure. Over half of the regional water systems do not meet the state’s standards to contain leaks, and 25% of the region’s water systems were identified as ‘Potentially At-Risk,’ ‘At-Risk,’ or ‘Failing’ by the CA State Water Resources Control Board’s 2022 Drinking Water Needs Assessment. Breakages and insecure pipes reportedly cost Southern California more than 84 million gallons of water every day.

For the residents of the 10400 block of Wilkins Avenue, a burst water main and sinkhole might have been one shocking event for a late Monday night, but for Southern California, it may be a symptom of a long-term, systemic problem that has been growing for a long time.