What causes broadband connection problems?

lyndsey burton
By Lyndsey Burton

computer bored slow

Over the years I've experienced various problems with my broadband connection. Sometimes it's slow speeds, occasionally the connection drops out and, rarely but worst of all, I've had no broadband at all for days and even weeks.

What causes these problems and why do they take so long to be fixed?

You shouldn't notice broadband: it should just work.

So when you do notice it, because it is doing something aggravating or, more aggravating, nothing at all, frustration can set in pretty quickly.

In this guide we try to stem that frustration.

More on your rights
Broadband contracts here
Right to complain here
Problems with tech support here
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We'll look at what causes the four main types of broadband connection problems and how long it usually takes to fix them.

Click through for more about:

Slow broadband speeds

Providers often offer limited support for slow broadband speeds because their terms and conditions of service don't list minimum speeds.

BT's terms, for example, say, "we aim to provide a continuous, high-quality service but we do not guarantee either the quality of the service or that the service will be available at all times."

Or, if you prefer, it's right there in broadband adverts: it's up to 16Mb, not at least 5Mb.

This laissez-faire attitude can leave many customers understandably frustrated.

One reader even got in touch to ask us whether their broadband provider should allow them to pay less for such poor speeds (we answered here).

On the other hand, slow broadband is one broadband connection problem that users may have some control over.

Self help

Poorly located or poorly configured wireless routers, uninstalled microfilters and home interference could all cause slow speeds and are all easily fixed at home.

There's more information on DIY fixes in this guide.

Traffic managed

The way a provider manages traffic can also be the cause of slow broadband and, again, this is something users have some control over.

Some ISPs slow broadband speeds on purpose in an attempt to manage heavier use of their network when everyone starts to log on at the same time, typically in the early evening.

When connections are slow in the evenings but work ok during the day, traffic management is a likely culprit.

For more on how each provider manages traffic see our guide to fair use policies here.

The best remedy may be using the Internet less during busy times, or if that's not possible switching to a new provider.

Capacity crunch

One more cause of slow broadband is when the combined bandwidth of many customers strains or exceeds the capacity of the local exchange.

It's the reason some ISPs have traffic management policies in the first place, to prevent too much bandwidth being used in one area at the same time: by slowing customer's speeds they can limit the amount of bandwidth that can be used.

Capacity crunch generally has two main causes:

When an exchange hits capacity, all customers in the area will suffer either very slow broadband speeds, drop outs or they may get disconnected entirely.

When it happens, the only remedy for ISPs is to install more capacity to handle the increased demand, or if the problem is excessive use by just a few customers to invoke their FUPs and cease service to the heaviest of users.

Waiting time

When Sky had some overstuffed exchanges, users started complaining in late November, Sky admitted the problem in January and fixed it in February and March.

So in that case, in the worst case scenario, it was four months from problem to fix.

Broadband keeps dropping or losing the connection

Intermittent broadband can be even more frustrating than a completely dropped connection, which obviously needs urgent attention.

Solving the problem

Solving the issue is the same, though, it's a case of problem solving, trial and error, and trying to locate the problem.

ISP technical support will typically take the same approach, starting with asking you to check wiring and equipment around your home, before running remote tests to try and locate the cause of the dropped connection.

The most common causes are either faulty or poor wiring in the home, including microfilters, or slightly more problematically, poor wiring between the home and the local exchange.

Dropping can also be due to over capacity, although traffic management is very unlikely to cause a completely dropped connection.

Waiting time

It's hard to give a time frame here because there are so many factors that could be to blame.

It can really just depend on both how quickly you whizz through the different suggestions of customer care and the technical support provided by your ISP to work out and resolve the problem.

No broadband connection

When the broadband connection is not working at all, first check service status at your local exchange.

If you have 3G or internet elsewhere you can check online, here are the service status sites for the biggest ISPs:

Alternatively, call your ISP and they'll be able to tell you about any problems in your area.

If there are no reported problems for an area, meaning only your broadband connection is down, it's back to trial and error problem finding.

There can be multiple causes for a broadband outage but it's often down to line or exchange connection problems.

Waiting time

If an ISP can't fix the problem remotely they have to call out a BT Openreach engineer.

In theory it should take about a week but, in practice, ISPs are reluctant to call out the engineer which is costly when it may not be necessary.

When they have resolved to get Openreach involved, engineer appointments are hard to book so you may have to wait again for a slot.

Find out more about this issue in our 'What causes technical support delays?' guide which is here .

New broadband or phone line provision delays

For a number of reasons, the part of the process you'd think broadband providers would be most invested in - getting the connection going in the first place - can prove to be a stumbling block.

New line trouble

A perennial problem is getting a new line installed in a property.

If equipment needs to be installed it requires an engineer visit, which for the reasons we mentioned above, can be tricky; if the property has a stopped line instead of a truly new line that might also cause problems, see below.

Switching problems

Another common issue is that broadband providers may need to basically communicate with one another during a switch, a responsibility many seem to find too burdensome.

Say, for example, that a new housemate moves into a shared home and wants to bring their previous broadband provider.

From the house's provider's point of view it's a switch, from the 'new' provider's view it's a home move. Simple enough: except that for one of our users it turned into a mire that took weeks and countless phone calls to sort out.

There are other more technical reasons why a new connection can cause problems.

One of the most common is known as a 'tag on the line'. This indicates that a line has been stopped, perhaps by the broadband provider of the property's previous owners and a notice served to stop supply by other ISPs.

To get it going again, the new provider needs to remove this tag.

Read more about this issue in this guide.

When it's not a problem...

Finally, though it's worth noting that new line problems are sometimes no one's fault.

New lines do need time to stabilise while the exchange runs tests on the line to determine the best speed which means that a new connection can be more prone to speed fluctuations and even dropping service before it finds its feet.

Waiting time

New line fluctuation can take a month to right itself.

Tag on the line and communication issues typically take a few weeks to clear up.


13 April 2017
Jeree Petrie


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