Mainly, because structural issues can be a complete black hole of money, time, effort--and it can be very difficult (and costly) to anticipate just how much money, time, and effort they'll consume.First, you'll need to figure out what's causing the structural issues--it could be settlement at the footers caused by ground water, it could be wood rot or termites in a beam, it could be masonry degradation caused by water coming off the roof, it could be improper drainage of the roof, it could be tree roots degrading the foundation, it could be a plumber who cut out a critical joist to install a line 20 years ago, it could be improper construction, it could be any or all of those things, and it could be any number of other potential causes.

If you are putting in an elevator if it goes to the basement and you have to have a pit did they put a drain in there as that slab is typically lower and if you have groundwater issues and the french drain underneath runs under the slab you will have water issues in there. 

Once you know the reason(s), for the flooding, then you'll be able to figure out a solution.I'd also strongly suggest that you don't re-finish the basement until you've determined the cause of the flooding and fixed the problem (last thing you want is to re-finish the basement, and have it all ruined again by another flood).I'd suggest first watching some videos on youtube on flooding, drainage, groundwater, french drains, sump systems, water catchment systems, etc, just to give you a better understanding on what can cause flooding, and what types of fixes might work. 

That means that the prior leaks and soil/groundwater contamination have already been taken care of. 

Mold was caused by shallow groundwater/excessive rain last winter.

However, high ground water levels, like those after heavy rain, can submerge leach fields, causing "over saturation" and system failure, leading to potential septic backup in the home and, if Santa Cruz County Environmental Health is notified, could trigger a ATD upgrade requirement.

Usually it's because there is lake water or drinking water or groundwater degraded that can be contaminated by septic or your project. 

Especially to replenish groundwater.5.

That area needs addressing, but it will be tricky to know if that is the issue, or if it comes from groundwater/waterproofing below.

By using solar lights for street lights, solar leasing for owners instead of only grid energy, using under ground water to water plants etc.