The answer to 'drainage system disease' is that common causes include clogged pipes, tree root intrusion, and improper grading or slope. Symptoms may include standing water, overflowing drains, and dampness around the foundation. Solutions can range from simple DIY maintenance like cleaning out debris to more complex repairs like replacing pipes or regrading the landscape.
If the drainage issues are severe or you're unsure of the cause, it's best to call in a professional landscaper or drainage specialist. They can diagnose the problem, recommend the right fixes, and ensure the system is functioning properly to prevent further damage to your home.