Question
I planted a weeping willow about 10 feet away from the edge of my pond (its about 40 feet away from my septic tank). I was hoping the roots would find there way to my pond as a water source insted of my septic tank, the area I planted the weeping willow is also very moist after rain has puddles for a few days then will dry . Do you think this is far enough away that it wont grow into my septic system? Thank you in advance!

Answer
Yes it is far enough form the septic tank--the width at maturity is about 35 feet meaning that the branch will spread out about 17 feet from the trunk. Roots extent out about 1 1/2 time the branches so the tank being 40 feet is fine.The roots will get into the septic lines and you did not mention how for these were. The roots will grow toward the easiest source of water so I think the placement near the pond is exactly correct.