Why waste water when you can make a simple reservoir delivery system.
To make a simple reservoir get some sort of a plastic bottle, I find a two liter coke bottle works the best!
Using scissors or a kitchen knife (please do not cut yourself) poke multiple holes in the sides of the bottle. Put the bottle in the ground then fill it with water.
Bury the bottle.
Plant your tomatoes near the buried bottle.
Your tomatoes (or other plants) wont need as much attention and will flourish.
You may have to refill the bottle every once in a while.
You could even put some plant fertilizer in the water and really watch them grow to their full potential!