The answer to 'why is my drainage system mud' is that a muddy drainage system is typically caused by a blockage or breakdown in the system. This can happen when soil, debris, or plant material accumulates in the pipes, preventing proper drainage and causing water to back up and create a muddy mess.
Some common symptoms of a muddy drainage system include standing water, slow drainage, and visible mud or sludge in the pipes or around the drainage outlets. To fix the issue, you'll need to clear the blockage and ensure the system is working properly.