For those that are interested in learning how a house with a yard sloped towards it fares here is our situation.
Built about 3 years a go, installed a patio on a concrete pad with a gentle slope away from the house.
0 Water issues, the water was like a river at the end of the patio but flowed away from the house around to the planned area on the side.
If you are concerned about a sloped backyard, or any backyard, I highly recommend installing a concrete poured patio that slopes away from the house. If concrete isn't your thing you can have pavers or flagstone installed on top of it (we did).