The Water Cure , if you read the link and the many benefits of keeping hydrated, why give that up. Its not always easy to get in as much water as your body may need or want. One statement I seem to have internalized is, if you are thirsty, you are already dehydrated, so I keep that in mind when I sip my water throughout my day. I read where children are better at keeping hydrated than adults since we do not pay attention to our body's signals for water.
I can recommend the Bowel Cleansing page here at Curezone too. Lots of great info to deal with constipation. I think there are other products, Oxypowder , Colonix, others which seem popular. Ideally, you want to get your body to process your food and liquids on its own...but it is a process.