A copper water main line enters my basement below grade. At the point where the line enters the concrete block, it is surrounded by a 3" PVC pipe. The space between the copper line and the PVC pipe is "sealed" with what appears to be some sort of hardened white foam. There are some visible cracks in the foam.

Water is trickling into my basement from the PVC sleeve. Not all the time. Only when there is a sudden thaw from 50 degree weather in the middle of winter (I live in Pennsylvania) or when there is a torrential downpour of rain. That is to say, it doesn't happen when there is a normal rain or drizzle, nor does it happen when there is a slow thaw, i.e., 35-40 degrees.

Indeed, about a month ago, we had unseasonably warm weather (50 degrees) and a rapid thaw, and water trickled in for about 2 -3 hours. Then the temperatures went back down, and the leak stopped. For the last 2 weeks, the temperature has gone up to 40 during the day and back down to 30 at night (a gradual thaw), and it has been bone dry. But then we had a torrential downpour of rain a week ago, and about 2-3 gallons trickled in.

The water authority "sounded" the line and confirmed that the cooper supply line is not leaking.

During the winter months, ice damming and freezing of the downspouts occurs directly above the side of the house where the water main enters the basement.

Plumber #1 said it is necessary to excavate the ground outside, and to re-seal the supply line from the outside, and fix any drainage issues. He gave me an estimate of $4,000.

Plumber #2 said it is not necessary to dig from the outside. He said that he could re-seal the sleeve from the inside. He also said that the source of the water was the ice damming in the gutter above, and that if the ice dams were eliminated, and the sleeve were re-sealed from the inside, the problem would be fixed. Plumber #2 gave an estimate of $800 to re-seal the sleeve from the inside.

Whom do I believe if I want to fix the problem correctly and permanently???

Plumber #2 is at least partially wrong, since the gutters are now clear of all ice and snow, and conducted the recent rainwater perfectly -- without any overflow. That leads me to believe that something more is necessary, than simply re-sealing the sleeve from the inside.

On the other hand, I certainly don't want to dig up my entire front yard, and pay $4,000, unless it's absolutely necessary.

Two additional facts that may be helpful. First, the water authority technician, who has absolutely no financial interest in the matter, told me that if it was his house, he would dig outside. Secondly, no other part of the concrete block or floor is wet -- the water is coming in solely from the sleeve. If there truly was an excess amount of water pooling against the outside of the basement, wouldn't the walls and the floor be saturated, too? Of course, the walls were painted by the prior owner. I don't think it was Dry-Lok, but it could still be masking dampness on the block.