basement floods during heavy downpours

I have a 15 foot long concrete driveway that slopes down sharply toward my garage door. At the bottom about 6 inches from the center of the door is a 10 inch square storm grate. The garage floor is about 1/2 inch above the bottom of the driveway.

So every 2-3 years when we get a monster rain storm the volume of water overloads the drain and rises over that 1/2 inch lip under the garage door and floods the basement. Last December was really bad when it flooded into the gas water heater. Needless to say this has got to stop - I have had enough.

Can anyone give me options for avoiding this? I know enlarging the drain is one option but we just poured the concrete driveway 5 years ago so I would hate to have to tear it up.

 

Since we can't see what you see without pictures, I would suggest changing the drain from a single small 10" storm to a full length grate drain running across the entire width of the opening. It is obviously something you can't regrade or make the water turn, so stopping it may be the only solution. Pro Series 5 in. x 40 in. Channel and Grate Kit with End Outlet-864G - The Home Depot

 

As was said, it's difficult to say without seeing more. However, if the driveway slopes significantly most of the water may flow toward your house. At 15' long you have a 150 square foot funnel of water. A rainfall of 1" or more could produce over 10 cubic feet of water so you need a drain capable of dealing with that much water. Obviously your little drain's not up to the task.

Beyond that, we can't tell if the driveway is sloped properly toward the drain.

In any case, the best option is to install a trench drain. And make certain to get one wide enough to handle the water.

As an alternative, there are garage dam/flood products available (such as weather stop and weather defender) that are cheap and easy to install. You can try that as an easy fix.

 

How large is the pipe and where does it go? A 10" pipe going into a 6" drain is probably sufficient. If it's going into a 2" drain, probably not.

I would start with the easiest (or the one that doesn't involve cutting concrete) and making sure the pipe is clear and it has a clear outflow.

You can also cheat a little by building up a lip at the edge of your garage. Basically, add a small 1-3" cement speed bump going into your garage. It may provide enough of a barrier for the water to drain where it's supposed to.