If you are seeing water show up in your basement, it's likely that you have some foundation damage. Water doesn't need to have a lot of space to sneak into your foundation, and each of the cracks it seeps into will get bigger and bigger as more water gets into the foundation, and the more damage that you are looking at and the more expensive your repairs are. There are things that you can do in order to repair your foundation. 

Find the Crack

The first thing you need to do is to find out where the water is coming from. You are going to look to see if you can find any cracks in your foundation. It will take a while for you to do, and if you don't have good lighting around your foundation, make sure that you take a flashlight with you so you can easily see. You may also want to make sure that you have something like chalk or spray paint so that you can mark the area of any cracks you find. Don't assume that the first one you see is the only one there. You can't judge where the crack is by where you are seeing the water, because water will move around and find the easiest way to flow, so your crack may be happening across the room from where you are seeing water flowing in, because that may be the easiest place for the water to show up. 

Repair the Crack

Once you find the crack, you are going to want to try to figure out what kind of crack it is while you are setting up to repair it. You are going to want to try to determine if it is something that you can easily repair on your own. If the two sides of the crack seem like they are offset or crooked, that can show that you have more trouble than just some water getting into your foundation, and you should call a professional immediately. Otherwise, you can probably get started patching it. First, you are going to want to make sure that the area is clean and dry. You can use a stiff brush to clean out all the debris. You may also want to use a chisel to cut out a little more material from under the edges of the crack. That will give the patch material more space to stick to. There are patch kits that you can use. Some of them are a basic patching compound, which would be good for smaller and thinner cracks. For a larger crack, you will want to use cement and pack it tightly into the crack and let it cure. 

If you are worried about the cracks in your foundation and the water getting in, you can always call a foundation repair professional and have them inspect your foundation and fix any problems.