Why does shower and sink water not drain fully when the RV is out of level?
In RV plumbing the grey water drain is unpressurised and flows entirely by gravity. If the vehicle is tilted away from the drain outlet, water stays in the tray or in a pipe elbow, leading to odour and, in winter, freezing. Levelling on two axes restores the design slope between the shower tray and the grey water tank.
In an RV the line between the shower tray, the sink and the grey water tank has no pump. The manufacturer gives this line a small design slope; the water drains fully only while that slope is maintained. When the RV is parked tilted on the left-right or front-rear axis, the design slope disappears or even reverses.
The consequences are these:
- Standing water collects in the shower tray, causing slipping and staining.
- Water left in the pipes breeds bacteria and smells; when the trap dries out, tank odour comes inside.
- In winter, water that does not drain freezes in the pipe and can crack the elbows.
- The grey water tank level sensor reads off from the true fill level.
Levelling solves this problem at its source. The KTS200 measures the slope on both the front-rear and the left-right axis and corrects it down to 0,025 degree precision, so the drain line returns to the position it was designed for. For users who on long stays deliberately want to leave the RV very slightly tilted towards the drain outlet, the Tare function can be set so that this reference is taken as zero.
The full topic: RV automatic levelling guide