One thing that can help you determine what you're getting into is having a core sample taken of the property. it will tell you soil type, groundwater and rock depth. if some rocks are big enough you might need controlled blasting. if your basement is below the stream bed grade wise, you would likely have to be pumping water 24/7 during the construction part. im not sure how well a poured concrete wall with the waterproofing on the outside will stand up to the water, but of course it would be better than a block basement. builders would reccomend under drains to drain the water. the best way to do this is mechanically, without a pump or you could still wind up pumping water 24/7 after construction is complete.

I am not going to type what I think of this.The BestMeeting Nina, the 94 year old woman next door who still drives to the store herself and is very sweetly Texas strong willed who came over to thank me for cleaning up "That mess"Up Next weekLast of the demoDumpster gets filledFramers / FramingElectrical workRough plumbing Earthwork with a Bobcat to protect the house better next time we get a 12" dump and solve the ground water penetration issues.

Also differnernt cities and municipalities have vastley different rules concerning zoning, utilities, curb and gutter, ground water run-off etc.  

Flushing household chemicals, gasoline, oil, pesticides, antifreeze, and paint can stress or destroy the biological treatment taking place in the system or might contaminate surface waters and groundwater.

Because of groundwater ingression via the backyard (another issue altogether), tenants have had to pull up the laminate flooring, exposing the original vinyl.

Are you going to have soil,ground water, etc around the tank tested to make sure there wasn't any leaks or spills?

has their been any activity in the area that would affect ground water? 

I am hoping on our next deal they will come down on interest a bit.Ok, so here's what the house looked like before we bought it:So far, we have painted the exterior, all new vinyl windows, new exterior doors, new garage door and opener, installing French drains and a sump pump due to there being a bad ground water issue in the crawl space last spring, new roof, opened up the kitchen, put in a french door, replaced all the wood flooring, tiled in bathrooms, framed in laundry and mechanical, shelves in the pantry, all new interior paint, heated flooring in master bath, can lighting.

Perhaps is sits on an area that was an old local drainage and the ground is slightly more pervious allowing the local ground water to collect and move down gradiant until it hits this house's basement.One thing that puzzles me is the why the existing sump pump is not dealing with the issue.

I spoke with a friend who is an environmental engineer who said that it could be the ground water (rare but possible).