5 gallon bottled water jug as fermenter?

I'm sure this has been asked many times, but can you use a typical 5 gallon water bottle as a fermenter, or at least a secondary? Like the kind from a water dispenser? Just curious what kind of mods needs to be made...

I'm looking for a cheap secondary.

Many of the plastics used for these water bottles do transfer some O2 through the material which won't harm water but could affect your beer. Thus, depending on how long the beer is in this bottle it might not be a good idea. These bottles may also be very difficult to clean properly compared to using a traditional bucket. I would recommend against using one fom my own brewing experience.

Ok glad I asked. I saw nothing wrong with using one. I guess a glass carboy is the best for a secondary. Arent plastic buckets bad as secondary's, since buckets expose too much surface area to air?

How are the better bottles?

Look on the bottom if its #1 plastic it's perfectly safe...I use them all the time. #1 PET is what better bottles are made of

Saying that most the water bottles I see are usually #7 plastic stay away from those...

Glass carboys are probably the best to use for long term secondary vessels followed by using Better bottles. Standard fermenting buckets are not ideal for doing secondaries.

I have one, I've used it......twice as secondary when adding fruit and once for primary when I wanted a small batch and my other primaries were full. That make 3 times I've used it in 4 years of brewing....maybe not my best investment. For only a few dollars more I could have gotten another bucket fermenter. I've quit trying to secondary and do it all in the primary now so that bottle just sits taking up space. Shucks, at least my buckets will stack.

Well, I've been wanting to make a coffee stout, and the directions say to add the brewed coffee when you rack to secondary. I guess I could add straight to primary after fermentation is done, but would it get mixed well enough? Or can I add it at bottling time?