Why is my internet data usage high when not home?

Bravo Ret60sb and Asch,

    Both of you are correct on the overview, but lacking in explaining terms.

1. De-Googling your phone. If you have an Andriod phone and paid in full. You will need to have your phone un-locked, and then load a clean Android image on it for full control. You can search the I-net for instructions and specific actions to take. Unfortunately you also may 'brick' (render useless) the phone. I have never done it personally. And this is NOT the venue to post questions. (Note: Ret60sb calls some of the activity 'automatic spyware'. This is more a IT insider phrase for the automatic updates. You can disable a fair portion by disallowing location services to some apps. Also do not simply 'accept' cookies'. With the California privacy law in effect, most sites now give you the option to change what cookies are accepted.)
2. Wireshark is a great tool … for any IT network techs, but something of an initial handful for the novice. That said, install it and run it. Record a session and save it. Then load it again into Wireshark and just page down through the information. Only small portions are in 'Plain English', but you can also see what IP addresses the information is flowing to. Again, use the I-Net to lookup and view more information on what you are seeing and how to utilize everything Wireshark offers.  (Note: the community venues here are NOT the place to ask questions or receive information. )
3. Final Note: The forums here are not places to ask for further information. Only new IT techs who have yet to get burned out may answer. And olde phartes such as myself just don't have the patience for the 'back and forth' needed to really help people.

Or someone flashed your router with an OpenWRT package like they did mine and are using it in a botnet. Just kidding: I mean it's probably automatic updates or the streaming devices doing the phone home thing as mentioned before. Additionally, devices are constantly talking to one another and sending signals back and forth. Some might see it as spyware but I think most of the proprietary question / response protocols are simply a harmless big data gathering technique by ISPs. I understand the discomfort and have a lot of criticisms of big ISPs myself. IoT devices can also use a lot of data or if you're on a mesh and you are correct about the anti-virus application because I know my ESET Premium shows a lot of connections when I look at my traffic. My advice, if you are noticing upticks and it keeps bothering you, take a look at your router traffic. If you own the router and it's a personal router and NOT a company's, then by all means get Wireshark and look what's happening. That way you can be positive. And yes, switch to unlimited 5G Internet if it's available in your area. ¡Buena suerte!

If people only knew the level of automatic spyware built into their Googled and iPhone type phones, and those phones upload that data via whatever means it has readily available (including your WiFi).  Your "normie" phone listens to everything you say, everything you do, every place you go, it sniffs the bluetooth environment you are in for other phones and wireless devices.  It uploads your days activities in the middle of the night, to include pictures, texts, locations, your contact list, who you were within 32 feet of at any point during the day, if its an iPhone it sends it to both the iCloud and to the Google servers.  If you have Facebook installed, it sends all or most of that same data to Facebook.  If you tweet, instagram or use classic social media it captures that data and sends it to the cloud based services for them to mine your metadata and place you into cohort groups for further monitoring - this monitoring is then sold to anyone who might be interested in knowing your interests, and those groups then target you for advertising or other nefarious purposes.  Ever wonder why new modern cell phones don't have easily removable batteries?  Because even when your phone is "off" it is still active.  The only way to truly silence it is to remove the battery or turn it off and place it in a Faraday bag.  Then take a look at your 4am data (midnight - 6am) and you'll discover that your phone is sending hundreds of megabytes (more than likely gigabytes of data) in the middle of the night while you are sleeping.  Get a De-Googled phone and this problem goes away - as long as you don't use social media on your De-Googled phone.

(Background: 35+ years experience with the Intel/AMD line of PC’s)

The short and sweet answer is that ALL modern devices now (Last 20 years) now 'Phone Home'. The same goes for any 'smart' devices in the home. The amount of data used varies widely and has to be taken individually to break it down further.

My previous post said ‘just turn off the WiFi router’, but truth be told, you would need to unplug every single ‘Smart’ device in the house (In the event of the lake house) to stop it.

Each 'Smart' device (phone, TV, Computer, Home automation systems (Nest / Etc.) will send and receive data from the Internet. It's written into the fine print of every device that people by and large won't bother to look at. And you cannot stop this from happening.

So don’t sign up for any ‘Internet access’ that has a data cap. Because at some point you are going to exceed the limit no matter how diligent you are.

Rsval wrote:

I am having the same issue. The device is at our lakehouse, no one is there. No devices are hooked up except for the nest thermostat... and I see multiple instances of data usage from 10mb to 224 during periods. Makes no sense but a good explanation would be welcome. 

I am new to Home Internet Light and I am also experiencing the same thing. I checked this morning and it showed almost 2GB of data usage at 4:30 in the morning. 

Since I have a fifteen day trial period, I am going to keep a close eye on the data consumption. A T-Mobile care representative is going to contact me next Sunday to see if things have changed.

There were several explanations given to me but I know technology and shot them down right away.

I used to have AT&T fixed wireless, which never used up data that quickly, even when watching full length movies.

Right now, I am annoyed with this usage issue. If AT&T provided a faster download speed, I would have never left them. In fact they allow 350GB for $60 per billing cycle.

The only short and sweet answer to this for non-technically minded people, is to power off your T-Mobile Gateway anytime it is not being used.

There are a number of reasons this data activity occurs but are far beyond the scope of this message and I am not going to attempt to even try and explain.

I am having the same issue. The device is at our lakehouse, no one is there. No devices are hooked up except for the nest thermostat... and I see multiple instances of data usage from 10mb to 224 during periods. Makes no sense but a good explanation would be welcome. 

Did you shut off your TV without stopping your streaming device?

There are many things that can take up large data usage if you set them up to automatically update software/firmware. For example, just one automatic os update for your PC can take 10+ GB. If you have multiple PCs, then they will each take up the same amount of data. Another example - Microsoft Office automatic update can take 1 GB or more per PC. Keep in mind that even if you have updates configured to where you manually accept the update, the update package itself may have already been downloaded in the background.