A persistent hum on your home phone line can be disruptive and frustrating, making it hard to hear conversions and concentrate on what you want to communicate.

Fortunately, phone hum is a problem you can pinpoint and remedy without waiting on a tech from your phone company. Some simple troubleshooting usually tracks down the root of the humming disturbance and leads you to a permanent solution.

Isolate Where the Hum Is Coming From

The first step to fixing a phone line hum is determining where it is — in your internal phone wiring or outside the house on your phone service provider’s network. The place to start is the interface box, the connection point between the external phone network and your home’s internal wiring.

Here is a step-by-step process to isolate the source:

  1. Find the interface box. It’s usually on the outer wall of your home where a phone line enters your house. Open the box and disconnect the test jack inside.
  2. Plug a corded telephone handset directly into the test jack. If the humming stops, this indicates the issue is within your in-home phone wiring. If it continues, the problem lies with your provider’s network or equipment.
  3. If the issue seems internal, plug your home’s wiring back into the interface box and check whether the hum persists on all extensions. Unplug each phone in your home one at a time while leaving another phone plugged in to check if the humming goes away when a particular handset is disconnected.
  4. Return to the interface box if the hum continues even with unplugged handsets. Systematically disconnect each set of color-coded wires from the terminals while listening to an extension phone. The hum should stop when you’ve identified the wires causing interference.

Check for Wiring Shorts and Interference

Inspect the connections for any shorts or loose wiring with the problematic wiring isolated. Tighten screws on the terminal blocks to ensure a secure connection. Examine the phone jack itself and use a continuity tester to check for breaks or shorts along the length of the wire. If you find the humming is emanating from a faulty jack, replacing a phone jack is not difficult.

Electromagnetic interference (EMI) is another common cause of humming and static. Verify that the wiring is not too close to electrical lines, fixtures, or junction boxes. Temporarily disconnect nearby devices, such as ceiling fans, lights, and appliances, that could produce disruptive signals.

Swap Out Defective Cables

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If you’ve ruled out wiring issues, you may need to replace a defective cable box. As a test, disconnect the wires at the jack and interface box and connect the blue pair. If the humming disappears, you can leave this blue pair connected permanently and disconnect the problematic wires where they enter your home.

Install a new home run line from the interface box to the phone jack location to remove the defective cable. This process is relatively straightforward but does require fishing new wires through walls and ceilings, similar to adding a phone extension. Alternatively, you can install a wireless phone jack system with a transmitter box that doesn’t rely on in-wall cables.

Inspect for Faulty Devices

Since cordless phones operate on the same frequency band as your wireless internet, they can cause interference, resulting in hums and buzzes during calls. Adjust the channel your cordless phone uses until you find the optimal one. Or consider replacing dated cordless phones with newer DECT 6.0 models that avoid interference with Wi-Fi frequencies.

Faulty devices like telephone sets, modems, and cordless phone bases connected to your lines can also be a source of humming. Try disconnecting and isolating each device individually to see if one particular device is the culprit. Devices with a bad ground connection or shorted internal components can produce noise. You may need to install a new phone jack if the wires inside the current jack are old or faulty.

Look for Outside Interference Sources

Even if your internal phone wiring checks out, you can still pick up a bothersome hum from outside sources. External interference usually produces a low 60-cycle hum.

Nearby power lines, electrical transformers on poles, and underground cables emit electromagnetic fields that creep into parallel phone lines. Overhead lines on the same pole as electrical and cable lines are especially prone to this type of interference. 

You can ask your phone service provider to relocate the lines to mitigate the humming. Installing noise filters is another option for outside interference. You can also ask a technician to run a tone test on the line for a more thorough diagnosis.

So, Is a Noisy Home Phone Line Fixable?

Phone line humming and other noise interference are often fixable with step-by-step troubleshooting and line maintenance. Go through the process of isolating where the humming originates, methodically testing wiring, and checking connected devices to reveal the root cause.

Simple fixes like securing wiring connections, replacing a faulty handset, or changing cordless phone channels will quiet the majority of hums. For persistent hums caused by defective cables or external sources, phone providers can usually implement repairs and noise filters to regain a crystal-clear connection.

While preventing and eliminating phone line hum may take patience, the loud buzzing and distorted conversations can be remedied cost-effectively without requiring a phone line replacement.

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FAQs About Noisy Phone Lines

What are the main causes of a humming phone line?

The most common causes of humming phone lines are wiring shorts, interference from nearby electrical devices and lines, faulty telephone sets, defective cables picking up interference, and external noise sources like power lines.

Where should I start when troubleshooting a phone line hum?

First, isolate where the humming originates — inside your home’s wiring or from the external phone network. Check connections at the interface box, then go through the phone devices and cables methodically to pinpoint the problem source.

Can I fix the phone line humming, or do I need a phone company technician?

Systematic troubleshooting often fixes causes of humming, such as wiring shorts, appliance interference, and faulty devices. But you’ll need a technician for outside issues like power lines and defective underground cables.

How can I get rid of the humming caused by underground cables?

Phone companies have a noise filter on the line where it enters your home. It suppresses electromagnetic interference from underground cables. Relocating your service line to reduce its parallel exposure to electrical lines may also help.

Why would I suddenly start hearing a hum on my phone line?

Aging and deteriorating components like worn cables can produce interference. New sources of electronic interference, such as a neighbor’s air conditioner or power generator, also cause humming.

What’s the best way to prevent my phone line from humming in the future?

Check your phone wiring and connections regularly to ensure everything is secure. Update aging telephone equipment and cords to newer standards when possible. Report any new community sources of EMI, like solar farms, to your provider.

Editorial Contributors
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Elisabeth Beauchamp

Senior Staff Writer

Elisabeth Beauchamp is a content producer for Today’s Homeowner’s Lawn and Windows categories. She graduated from the University of North Carolina at Chapel Hill with degrees in Journalism and Linguistics. When Elisabeth isn’t writing about flowers, foliage, and fertilizer, she’s researching landscaping trends and current events in the agricultural space. Elisabeth aims to educate and equip readers with the tools they need to create a home they love.

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Sabrina Lopez


Sabrina Lopez is a senior editor for Today’s Homeowner with over 7 years of writing and editing experience in digital media. She has reviewed content across categories that matter to homeowners, including HVAC services, home renovations, lawn and garden care, products for the home, and insurance services. When she’s not reviewing articles to make sure they are helpful, accessible, and engaging for homeowners like herself, Sabrina enjoys spending time with her family and their two parrots.

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