My erf is a warning to others about why to rather buy a house on a level plot.
Each winter we have some serious ground water building up and flooding a portion of our front yard. I had a catchpit installed that takes the water around the house to the back where it's discharged again. The problem with Westering is that there is a metric crapton of rocks, and there is a big seam that runs across the whole front of the yard so the water can't permeate it, so it just builds up until eventually it floods higher than our paving.
In summer it's not a problem probably due to the longer daylight hours evaporating all the water before it can become a problem.