The answer to 'why is my carpet stained' is that there are several common causes, including spills, tracked-in dirt, pet accidents, and general wear and tear. Carpet stains can range from small spots to large discolored areas and may be caused by a variety of substances like food, drinks, mud, or pet urine.
The best solution depends on the type and severity of the stain. For fresh spills, blotting the area quickly with a clean, absorbent cloth can help prevent the stain from setting. Deeper, set-in stains may require more intensive cleaning methods like using a carpet cleaner or calling in a professional carpet cleaning service.