It is illegal to run any waste water on top of the ground, even washing machines. In the biz we call water from sinks, showers, and washing machines grey water. It is much more common to find grey water pipes than black water (think toilet). Below are some pictures I took today of a small plastic grey water pipe sticking out of a bank along the road. Notice the erosion the waste water has caused. Your pal the Envirocapitalist.