Both, If you open all the faucets to let the air flow to prevent suction. But normally there is a freshwater tank drain, which is faster. Then, to clear the lines, you open the low point drain after opening all the faucets.
Joan & Angus Campbell
Building in Las Cruces, NM
2019 Pinnacle 36SSWS
2019 F350 DRW Lariat CC Long Bed Diesel "Sheila"
3 Chihuahuas and 4 cats
We don't camp, we don't glamp, we LIVE.