Whoa, guys...
The fact that the sump pump kicks on when it rains is a good indication that the drainage system he has is working fine. The fact that the sump also has water in it pretty much year around is also a very good indication that he's got a fairly high water table.
In that situation, excavating an additional indoor perimeter drainage channel will likely do one thing...
Cost him a LOT of money and still not solve the efforesence problem.
The effloresence is most likely coming from the moisture from the high water table, and short of busting up the slab I doubt that any amount of perimeter drainage is going to do a thing about it.
Thank you.
There is good drainage under the slab. There is a cut around the whole slab on the interior also.
The only way to lower the water table would be to dig a deeper pit. I don't think that would work well because I would be trying to drain the whole neighbor hood at that point. The water is at least 6" under the bottom of the concrete usually.
The soil here is 3-4 inches of top soil, then hard clay/shale mix. My guess that extends to bedrock.
The house is a ranch. The down spouts on the left end of the house go into the storm drains. On the right end (which is also the garage end) drain onto the ground. That side of the house actually slopes away and sends the water into the neighbors side yard.
