I paid a family friend to lay a concrete patio attached to my back door. He laid it too high. Specifically flush with the back door. I know now this can be a big water issue but can’t imagine how to fix it. What are my options?
There are quite a few options in the realm of "drive way" drains as pictured below. If you have a place to drain the water to it might work.This would be installed just outside the door. You'd have to have someone with a concrete saw cut in the groove for the channel. Hopefully the slab isn't too thick. Then install the channel, draining to a low spot. Whether this is a solution for you depends upon if you can live with the aesthetics and if you have a lower place you can drain the water to. Product recommendations are off topic here, but you can do some simple searches on google for driveway drains and go from there.