No. Both water-based polyurethane and oil-based polyurethane have equal waterproofing ability. If they are applied on hardwood floors, they seal the surface and create a layer of protective water-repellent material that does not allow the water to seep in the hardwood. But even water-based polyurethane cannot make hardwood floors 100% waterproof. There is reliable evidence that suggests that they are more waterproof or less. That is why both are considered equally effective.