The US Center for Disease control recommends that any carpet that gets wet be completely dried up within 48 hours or mold will settle in, at which point the carpet will need to be removed and discarded.

The ideal for you would be to have installed an interior perimeter basement drainage system that would intercept and collect ground water, diverting it to a sump pump, thus keeping the basement from leaking.

However, if you chose not to do so, your best choice would be plastic, 100% waterproof and non absorbent basement flooring tiles, and here’s why:

First, they are completely waterproof. The will not soak up water and will not get ruined even if your basement is under water.

Second, they are floating, interlocking flooring solutions. You can remove them to inspect the slab, you can switch them around, you can remove a few pieces without disturbing the rest of the tiles.

Third, the finished surface is raised from the basement floor by a system of pegs. That creates an air flow underneath the tile that allows the leaky slab to dry, while keeping that moisture from evaporating into the basement. In addition, it creates a comfortable surface to walk on barefoot. The surface of the tile is in average 10 degrees warmer than the cold basement floor.

ThermalDry brand tiles come in different finishes, including vinyl, parket and carpet. I am adding more info on the links below. BasementGal

Edit: The reason outdoor carpet won’t work, for those suggesting it is that it’s made to be outdoors, therefore it will dry out in the sun after a day of rain. With the location it’s to be put in, there won’t be any sun or warm weather to dry it out. Moisture will remain trapped up under the carpet. Even if the carpet itself doesn’t mold, the backing and the tile beneath certainly will. And that festering mold and mildew is not at all healthy for any of the houses occupants.

Just my $.02 good luck with it. LogicBeforeLibido