I noticed a small moist patch of the floor near a radon mitigation system. However, I suspect that it has little to do with the radon system but was due to failed caulking at the cove joint, as there seems to be dirt in a small segment of the caulking.
A recent heavy rain likely raised the water table so high that even though our sump pump worked properly, there was still a small amount of water seeping in.
Is my assessment right? If so, what is a good caulk chemistry to use?
There are suggestions such as
Quikrete polyurethane sealant,
latex-based Drylok waterproofer.
Updated: A picture of the sump pump. The sump pit is 19 inch in diameter and pretty deep, but the float makes the pump to operate only between a limited depth (as you can see from the water marks in the picture).
Best Answer
Water should never come up from below the slab. If water is coming up then your sump pump is undersized and not handling either the influx of ground water or the rain and influx of ground water. The sump pump should have a high level alarm. If the water ever gets anywhere near the bottom of the slab the alarm should be going off.
You aren't going to be able to turn your basement slab into a boat bottom if water is that high in the water table then water will wick up through the porous concrete slab or through any number of penetrations or cracks. You might want to seal the crack to prevent radon / water moisture from entering your basement in that case I'd go for the quikrete product.