PigHunter and bruisedsausage you both did your math well and 99, you hit it close enough too. The pump/volume/time program I used was based on rounding off to only four decimals during calculations and the input specs were based on a container which was one square mile by eleven feet deep and a pump that would pump one gallon per second. The program was supposed to account for leap years starting this year. The answer that the program came up with was 72 years, 252 days, three hours, 25 minutes, and 10 seconds. With the rounding off of some numbers to only four decimals, it could make a pretty good size error over that many seconds and gallons, so my numbers are merely approximate anyway.

This question came up to me a little differently by my grandson who asked how long would it take to drain a tank that was one mile wide by one mile long by one mile deep with a drain rate of one gallon per second. He had this on a quiz with multiple choice answers. In his problem, it would take over 30,000 years to drain.