If you're getting water on the floor that doesn't mean the leak is at the cold joint; it could be anywhere along the wall.

You haven't given any detail. But I would first look at all the obvious culprits on the exterior--reverse grading, broken eavestrough, broken downspouts or downspouts that dump water too close to the foundation. Walk around your house during the next heavy downpour to see where the water is going.

Downspouts long and okay, gutters okay. Grading was improved, but could probably use a little more grading. I had water that was somewhat puddled underneath the carpet and it seemed to have originated from behind the wall, not coming up from through the cement floor. Need advice on how to get at the wall in order to see if there is a problem with the wall itself. I believe I have mildew issues behind the wall due to a noticeable smell...

Thanks. No cracks that I can see on the outside of the house. No windows on that wall. Carpet and padding has already been pulled back and away form the wall, and condition is good. Mildew is most likely coming from inside wall.Pretty certain I need to open the drywall up and at the very least clean and remove the mildew, etc that is present and check for cracks, etc.

Just need to figure out how to deal with the framework in order to gain access to the floor joint and the rest of the wall. If anyone has advice on this I'd really appreciate it.

If there's no dehumidification and inadequate insulation, you will get condensation on the foundation walls feeding mould. So it may not be a leak at all. The framing is usually an inch or two away from the wall to make up for irregularities in the wall.

If you end up ripping out a section of wall, don't put it back together the same way. Use appropriate insulation.

Here is a link that might be useful: Building Science Corp. on Basements

Update:

After doing some more digging (literally), I did find a crack in the foundation wall on the outside of the house, and the location corresponds with the area I had the water issue with in the basement. I spoke with a basement repair guy who quoted $1000 to inject urethane into the crack and then to prevent expanding, add a carbon fiber patch that covers the crack.

The process seems fairly basic. I'm pretty handy, so is this something I could fix myself? If not, any idea if $1000 is a pretty standard price? Seems like a lot for a couple hours work, which does not include fixing the drywall.

Get some competitive bids. It can also be a DIY repair, but I have no experience with that. See link.

As the link explains, it's also important to see if this is a shrinkage crack or something more serious. The crack repair people working for subdivisions here usually just fill the crack from the inside. Those working for homeowners with finished basements tend to excavate from the outside. After the repair, they cover it with several feet of a Delta-Type membrane. This way, in case the crack expands, water will be kept off the wall.

Here is a link that might be useful: Inspectapedia on Crack Repair

several feet of a Delta-Type membrane

To clarify, they put in a five or six foot width of membrane. If the whole foundation had been originally covered in membrane, chances are the crack wouldn't have leaked in the first place.

Just yesterday we discovered a wet place on the carpet in our finished basement. Called in a professional right away. Our house is 9 years old. The gentleman checked our whole basement carefully, indicated that his expectation is a crack from the bottom of the window opening and water seeping out from under the drywall. We removed the portion of drywall and insulation under the window, and sure enough, there is a crack, looks like settling, from the window edge to the floor. Drywall was wet for a few inches from the floor. Pulled bak the carpet and used heaters and a fan to dry it up. The man is coming back to use the injection of polyurethane and membrane method to seal it up. Our ground is frozen solid right now but we have had heavy rainfall over the last couple of days. The expert told us he had had 18 calls in the last 24 hours, as the earth cannot absorb the water just now and it runs down between the ground and the foundation, finding any way it can to run, in our case, through a small crack and into the house. In the Spring we will make sure that window well drains are clear, that water is directed further away from the house, that the grading is improved a bit. May dig down by hand to see if anything is required from outside. All the comments here have been incrdibly helpful, as we have had absolutely no experience of this in the past.

Thank you all, and good luck! I may post again after all is said and done to report degree of success.

Foundation cracks most often develop under and near basement windows as they are stress points. A membrane over an interior epoxy injection serves no purpose.

Epoxy injection into wall crack. Photo: Heather Joy Investments Ltd.