I really like the precision of a liquid liner, but hate the somewhat glossy look. So my solution to this problem is an eyeliner sealer. I use the Cinema Secrets Eyeliner Sealer mixed with an eyeshadow (my current favourite is NYX black) and voila - a perfect line.
So today I thought, what if using water is just as effective as the eyeliner sealer and decided to do a little experiment. I did one eye using the eyeliner sealer and the other using water. Hate to disappoint, but the eye that was done with water had smudged approximately 30 minutes after it was done. The other eye is still perfect 10 hours later. And yes I did spend the whole day at work with one eye perfect and the other smudged...hopefully not a lot of people noticed since i was wearing my glasses. Oh the things I do for makeup ...lol
Cinema Secrets Eyeliner Sealer - $7.49 USD on the site linked above
Lise Watier Metamorfix Liquid Transformer - $14 CAD at Shoppers
Makeup Forever Eye Seal - $20 USD at Sephora
Some eyeshadows are not formulated to be used with an eyeliner sealer (or water for that matter) and will glaze over and harden. There isn't really much that can be done after the fact, so I suggest you test a corner of your shadow first.