It is usually the side that get's the most Sun on a Tile Roof, that bleeds the most. LOL, the "blood" that we see wash off a tile roof is really the old oxidized film, so the side of the tile roof that gotthe most Sun over it's lifespan, will Bleed the most. I do not usually suggest ANY soap or surfactant on a tile roof Joseph, it makes them even more slippery, but when you have a tile roof that you KNOW is gonna bleed, here is what to do. Use a lot of surfactant, and some TSP if you have or can get any. Here is why. The TSP will really help loosen the old oxidized layer, and so will the surfactant. This will help the roof pretty much all Bleed Out, in only 1 or 2 rains.I didn't know that about old tile. This particular roof I was running into bleeding only on the south side. It was a chore keeping the white fascia rinsed clean. Great tip Chris thanks again.