[BlackArcher101]

I don't think lowering of the slope is going to help with your water issue very much. The clay will still be there and instead of the excess running off, it will start to pool.

My father had bad clay soil as well, and was very difficult to water.

Start with aerating your lawn to see if that helps. If not, I would bring in some nice dirt and resod. (You'll have to regrass anyways if you change the slope).