This article details some of the most common Internet activities that can generate high data use. This is meant as a guide and does not go into specifics.

The following questions come up quite frequently:

• "Why is my broadband usage so high?"
• "I've never used this much data before."
• "Everybody was asleep when this data was being used."
• "I wasn't even home on that day!"

So we thought it might be useful to elaborate a little bit about what could possibly be causing your data usage headaches.

Please remember that all usage generated is the responsibility of the user so it is important to monitor both your use in My One NZ or Customer Zone and your online activities.

Things to know

In accordance with the Telecommunications Information Privacy Code Of 2003 (PDF) , we can neither see exactly what you are using your broadband for, nor are we able to supply this information to you on request. We will investigate bandwidth disputes to the best of our ability, within the parameters noted in the following two points.

We are able to establish whether or not the queried usage was accumulated from your connection and IP address, and if so, the usage will be deemed to be legitimate and you will be billed for overage accordingly.

In the extremely unlikely event that you are the victim of a DDoS attack, your connection may register abnormal data usage. While we are rarely able to pre-emptively track this kind of activity, if you query it with us, we will be able to determine if a DDoS attack is responsible for your usage and we will remove the charges from your account. If you are the originating source of the DDoS attack, we will evaluate the situation on a case-by-case basis.

What can I do?

While you are responsible for the securing your own broadband connection, there are some things that you might have overlooked. To help you determine what the cause of unusually high usage may be, you should consider the following:

Operating System Updates.

Most computers update their software on an automatic schedule, typically between 10pm and 3am. The vast majority of updates are quite small (a few kilobytes), but in the case of major Windows releases and service packs or Apple iOS updates, several Gigabytes could be used in a matter of hours. Multiply this by the number of devices in your household that each require the update and usage quickly adds up.

Video Streaming Sites.

Streaming videos online, especially in HD, uses several megabytes per minute of video. The higher the quality of the video stream, the more data is used. For example, streaming an HD film or TV series from Netflix could use as much as 3GB per hour. In the case of YouTube, there is now an 'Autoplay' feature that automatically starts playing the next video when the previous one has finished. Leaving a YouTube video running on your computer can result in a significant chunk of data being used!

Fire Sharing/Peer-to-Peer Software

If you are using file sharing software (such as BitTorrent), the application may be using up your data by running in the background on your computer. These kinds of applications run every time you restart your computer and continue to upload or download information without your knowledge.

Tip: Remember to disable file sharing software when you are not actively using it.

Game Updates and Game Consoles.

Downloading new games from online content providers (eg. Steam) can rack up several Gigabytes of usage in a very short space of time. Be sure to check the file size of the game you want to download before you click!

Many games also complete their own updates via a built-in client. These clients may have several titles attached to each one and frequently update all game titles associated with the client.

Tip: Uninstall games you are no longer actively playing to avoid accidentally downloading large content patches and expansion packs.

Online Backups

Applications like DropBox, CrashPlan and JustCloud.com allow automatic schedules for backing up and synching your data to the Cloud.

Tip: Check to ensure that only critical information is backed up on a regular basis, as this could quickly use up your data allowance.

Viruses/Trojans.

Unfortunately despite your best efforts to secure your computer, you may suffer an infection from a virus or Trojan. These malicious scripts could be using your connection to:

• Send unsolicited email spam
• Launch DDoS attacks
• Provide unauthorised access to your computer by a third party.
• Install keyloggers, which may record your credit card or banking information.

Tip: You may need to Google 'how to remove malware' from your particular device, but generally steps will include downloading a malware detection programme such as MalwareBytes to help with the disinfection. Note: Please be aware that due to the huge variety of operating systems and risk factors involved, our support staff are not trained for this particular task.

Therefore this is unfortunately not something we are able to assist with. If you even remotely suspect your personal banking account may be compromised, contact your bank to keep an eye out for untoward activity on your account and consult an IT professional for assistance in securing your computer.

Video conferencing.

You may not be aware, but HD Video calls using applications such as Skype can use up to 22.5 megabytes per minute during a HD Video call. That's a whopping 650Mb for a 30-minute conversation!

In reality, because Internet speeds are variable and the application will reduce the call quality to retain the connection, the average call usage will be much less; but this is definitely something to keep in mind when you mentally try to assess your usage.

Large email attachments.

An often overlooked problem when your outgoing data seems high is to check if there is anything in your email client's 'Outbox'. If you have tried to send and extremely large attachment (such as a collection of very high definition photographs, for example) your email client may time out and keep the item in your Outbox. As long as the connection is maintained, your system will continually try to resend (Upload) the item, resulting in a large portion of uploaded data.

'Outbox' items disappear almost instantly. There should be nothing in your 'Outbox' folder.

If you spot anything that appears to be staying in your 'Outbox', you can try to move the item by dragging and dropping it into your 'Drafts' folder. Open the item and check if you are able to alter the size of the attachment.

Resize images to more manageable sizes or use a compression tool to reduce the file size of documents and other files.

Unsecured Wi-Fi.

If you have a weak Wi-Fi password or do not use encryption for your Wi-Fi network, your neighbours could be using your internet connection without your consent.

Ensure your password is complex, difficult to guess and not a dictionary word. Change it frequently or as soon as you suspect unauthorised access. Use an encryption technology such as WEP or WPA.

Disable SSID broadcasting to make it even harder for unauthorised users to access your connection.

Your Kids and Visitors.

If you're sure that none of the above are responsible for your high data usage, you might need to consider your children's usage patterns and educate them to help them understand how their habits may be impacting on your overall bandwidth usage. If you have extended house guests or a live-in roommate, it may pay to have a conversation about your bandwidth limits and expectations around what acceptable levels of usage are.

Resold Modem/Routers.

If a modem is to be resold, or gifted to someone else then the user information will need to be cleared from the device.  If someone else connects a modem/router onto the internet with your username and password, then you will be responsible for their usage.