Does it hold water? Or does water/dog urine seep through it? Thinking of using this as trainihg patch for upstairs back porch area.

Yes, Global Syn-Turf products are designed to be permeable, allowing water and other liquids like dog urine to seep through. The synthetic grass has a backing with drainage holes, ensuring that liquids pass through quickly, which makes it an excellent choice for areas like your upstairs back porch. It is both practical and hygienic for pet training.