Thats alot of money. I just looked on Interlinks site and they are running about the same for an external pump out. I did see that they had in tank pump outs that were a fraction of the price, but I am not familiar with pump outs to know if one is better or more efficient. but for $1700 I would think you could get a huge waste tank made for you. I have a 100 gallon tank in my truck and it is good for my setup and I can do most days with out having to worry about filling it.