After I blow out all lines once, I blow (at lower pressure) through the anti-freeze line attached to the water pump which clears the pump chamber and the line out of the pump. Then do a final blow out. I know some don't have the A/F line in their rvs, but you could still access the inlet line and do same. Never have had a problem doing this. And it will clear all lines mucho better!!
On my trailer, city inlet is a long way from pump, so the line can hold a good amount of water!! I have installed a city inlet (w/out check valve) in sidewall near pump (for access to water outside) and it is used to blow out the lines, so not much left in the line from pump.
2016 Timber Ridge 280RKS
2003 Excursion XLT V10 4:30 Axles
DualCam HP 450W Roof Solar/320W Portable