If you're looking for the best water back up sump pump, you'll want to consider a few factors. First, think about the capacity of the pump. A larger pump will be able to move more water more quickly, but it will also be more expensive. Second, consider the head pressure. This is the pressure that the pump can generate to move the water. A higher head pressure will be better for moving water up hills or over long distances. Finally, take a look at the warranty. A longer warranty will give you peace of mind in knowing that your pump is covered in case of any problems.