I am taking on water from a recent high water table. This home has been dry for 12 years. All drains flow away from house. We had 5 inches of water, now a week later its 1-1.5" per day. I can pump it down, but it returns. Can I pump it down, then put a sump pump in or will the high water table create a bigger mess for me?

If my sump pump has an outlet pipe sizing of 1.5" what are the draw backs from using existing 1" pipe? Should I just run all new 1.5" to match the pump? Running up 10 feet, and 50 feet of horizontal then out to an existing 4" PVC to street.

If I understand you correctly, the water is already getting into the house. I doubt that making a hole in the floor for a sump will make it worse unless there is a lot of hydrostatic pressure under the floor.

As to the outlet piping for a sump pump, bigger is better. The smaller the pipe, the greater resistance to water flow and the less your pump will move for a given energy input and time. If at all possible get the output pipe at least as big as the pump outlet. A bit bigger, as in 2 inch, for the 50 ft run would not hurt.

I agree with EPM, a sump pump would help but without a curtain, perimeter tiles at the foundation, it will not be a great fix. If you have a basement with no sump and no tile the correct fix is to jack hammer a trench at the perimeter of the floor, install tile sloped to sump and then a pump. Sump Pit Installation - Don't Let it Get You Down in the Dumps (http://ezinearticles.com/?Sump-Pit-Installation-Dont-Let-it-Get-You-Down-in-the-Dumps&id=2027992)

You should always match the pipe size with size of the pump outlet. Do not reduce. If you are getting lots of water, get 2" pump with 2" discharge pipe...