Rotating Power Outages

What is a Rotating Power Outage?

In the event of a state-wide power shortage, the California Independent System Operator (CAISO) will order Azusa Light & Water (ALW), and all other load serving entities under its authority, to shed a certain amount of load; usually up to 5%, depending on level of power shortage. To achieve this reduction, when cutting water facilities is not sufficient, ALW would temporarily interrupt a block of customers for about an hour, then interrupt a second block of customers of about the same size for the second hour of the event while restoring the first block at that time. This rotation of customer interruption would continue until the power shortage event has passed.

What is ALW’s protocol when a rotating power outage order is received?

To minimize inconvenience to its customers, ALW will always cut water system pumping facilities prior to implementing general customer rotating outages. The water pumping facilities require a significant amount of energy, and cutting them first may be sufficient to comply with CAISO load reduction orders.

What can I expect if my power is interrupted pursuant to a rotating power outage?

If your power is interrupted pursuant to a rotating outage you can expect it to last approximately one hour, and we will not interrupt service to any customer more than once per day. Power shortages will most likely occur during daylight hours, so lighting should not be a problem in most cases. We recommend that you keep your refrigerator closed, as much as possible, to preserve food temperatures during the hour-long power outage. Also, electric garage door openers will not work during power outages, so if manual garage door operation is difficult you may choose to park outside of the garage on a day of potential rotating power outages.

Will I be notified prior to a Rotating Power Outage?

ALW will advise its customers of potential power outages throughout the day of the power shortage event via the City website, email, and social media. Unfortunately, it is not possible to notify individual customers directly prior to interruptions because the load reduction must be executed within 10 minutes of receiving the order and the list of customers interrupted will change throughout the event. We apologize for this inconvenience.

To sign up for general notifications for potential rotating power outages, please send an email request to If you are receiving the Azusa News & Events monthly newsletter, there is no need to sign up since you will automatically receive this notification. Please note that the notification is for imminent rotating power outages ordered by CAISO only and not for all power or water service interruptions.

Is conservation still needed?

Yes! Conservation is one of the primary methods used to avoid the need for rotating power outages during heatwaves, which significantly increase power demands due to air conditioning loads. ALW asks that you conserve energy from 3 PM to 10 PM to help avoid the need for rotating power outages.