How to Fix ADT Alarm Beeping After a Power Outage

House with power outage showing flash lights and lantern on table with water gallons and supplies.House with power outage showing flash lights and lantern on table with water gallons and supplies.

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Great, you’ve been standing in a dark house for who knows how long, and now that the power’s back on, your ADT Alarm won’t stop beeping. Before you pick up the phone and give ADT a piece of your mind, stopping the beeping actually takes just a few seconds of your time.

Here, we’ll talk about how you can fix your ADT Alarm’s beeping after a power outage. We’ll also provide information about what the beeping means and when it’s necessary to call in an expert.

How to Stop ADT Alarm’s Beeping

Your ADT Alarm keeps working even if your power goes out. That’s because it runs on a backup battery. However, if the battery is low, the alarm will beep, alerting you to change it.

You typically have two options for stopping the beeping:

  • You can press the pound key.
  • You can press the “off” button.

Remember: this is only a temporary fix. You’ll need to eventually change the batteries to get your system back on track.

If your system’s still beeping, your best bet is to change the batteries. The types of batteries you need depend on what type of alarm system you have. To change your ADT alarm’s batteries:  

Put Your System into Test Mode 

Before doing anything else, you should put your ADT Alarm in “Test Mode.” This notifies the system that you’re making changes and doesn’t send alerts to ADT. You can put your alarm into test mode using the app, but we recommend doing it from ADT’s website:

  1. Go to and enter your login information.
  2. Choose “My Alarm” from the dashboard.
  3. Click “System Management.”
  4. Click “Place alarm on test mode.”

If you have problems with these steps, watch this short video about putting your alarm in test mode via the app. Alternatively, you can call 888-ADT-ASAP to put your alarm in test mode. Be prepared to provide information about your ADT account and where you live.

Insert the New Batteries

Your ADT Alarm is a sensitive piece of technology. As such, the process isn’t as easy as pulling it off the wall and putting new batteries in. You’ll need to:

  1. Open your system’s front panel. You might need a key to do this. If so, it should be located on the panel’s top left-hand side. Disconnect the wires from the battery. You can do this by unraveling the wires around the nodes.
  2. Connect the red wire to the battery’s red tab.
  3. Connect the black wire to the battery’s black tab.
  4. Close the front panel.

Take Your Alarm Out of Test Mode

To take your alarm out of test mode via the website:

  1. Go to
  2. Choose “My Alarm.”
  3. Go to “System Management.”
  4. Select “Stop Test.”

Taking your device out of test mode is not the same as arming your perimeter. You will need to enter your password to re-arm your system.

Wait 48 Hours

Following these steps does not guarantee immediate success. In fact, it can take anywhere from a few minutes to a few days for the “Low Battery” indicator on your ADT panel to turn off. However, your ADT Alarm’s beeping should stop.

What if My ADT Alarm Is Still Beeping?

Consider how the following could address your situation:

Recheck the Battery’s Connection

It’s possible that you successfully replaced the battery itself, but energy isn’t flowing through the wires. Depending on your system, you may need to wrap the copper ends of the wires around the battery’s nodes.

On the other hand, make sure the new battery itself has a charge. You can do this by using a battery checker tester or using batteries straight from the packaging.

Reset Your System

Resetting a malfunctioning device is the “abracadabra” of the technology world. Nobody knows why this fixes so many errors, but it does. Try resetting your system if the beeping won’t stop. ADT provides these resources:

Cut off the Alarm’s Power

Your alarm can’t beep if it doesn’t have a power source. First, put your alarm into test mode using the information outlined above. Then:

  1. Locate your home’s fuse box.
  2. Shut off power to the wall/room your ADT Alarm panel is in.
  3. Remove the batteries from the device.
  4. Wait a few seconds.
  5. Put your alarm back online by replacing the batteries before turning the power back on.

The beeping should stop when it powers back on. Remember to take your alarm out of test mode beforehand.

Call ADT

ADT says that if your ADT Alarm still beeps after a power outage for 24 hours, call customer service. There could be an underlying problem as to why your system is malfunctioning. You can log into your account to contact ADT via the internet, or you can call 1(800) 521-1734 to speak with a representative. 

In Conclusion

Turning off your ADT Alarm after a power outage should be as simple as pressing the pound key or the off button. If these measures don’t work, however, chances are you need to replace the batteries.

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