I have had enough with this issue so coming to you guys for ideas. Last year we put in a pool and paver patio. We already had an existing concrete patio and the thin pavers were placed on top of the existing patio.

Any time hard rain hits the back of the house, water gets under the door and covers the garage floor. We never had this issue prior to installing the pool so it obviously has something to do with the patio now being raised.

The patio is now essentially flush with the door threshold. My dad and I put in a new exterior
door last year as the bottom corners of the old door had rotted over the years so I thought a mew
door might fix the issue. It did not.

Do any of you have any ideas as to what I could do to keep water from entering the garage? FYI it comes in under the threshold.

 

Well since the paver patio looks to be about 3/4" higher than the garage floor, yeah I'd say that's the problem. There is no good solution to this since you raised the exterior side of the door up higher than the concrete in the garage. Water runs downhill. About all you could do is remove the door, mortar down some solid concrete cap blocks that are maybe 1 1/2" thick... then put the door back in, set it on a heavy bead of sealant or on top of a sill pan. Then you'd have to really step over the threshold when exiting the door from the inside.

 

I'd do as XSleeper suggest, as well as add a sill pan.
To late now, but when I install a new door I buy one with flat jambs, and buy the newer doors that use a composite material at the bottom of the jamb and use PVC brick molding, that way there's no more rotting issues.

 

When I added a door to my garage I had the choice to make it at ground level or step up over the foundation wall. I chose step up. Glad I did. Always have entrance above ground level.