They say creatine causes water retention. At the same time they say you have to drink more water if you take creatine in order to avoid dehydration and kidney problems. Doesn't it sound illogical? If your body stores more water why do you need to drink even more?
Creating draws more water into your muscle cells, which helps to increase muscle bulk and also increase protein synthesis (1)(2), although the total amount of water involved is relatively small. It may be this, or anecdotal evidence that creatine causes cramps - which does not appear to be backed up by evidence (3)(4), which has caused some articles to recommend increasing water consumption.