What it means
The grey waste tank has reached its practical limit. Keep using sinks and the shower and you risk it backing up into the van instead of draining away.
What to do
- Head to the nearest designated waste disposal point.
- Empty via the outlet ('blade') valve into the proper drain, never onto the ground.
- Give the tank a rinse through with clean water afterwards to reduce odours.
Likely causes
- Normal use over a few days without emptying
- A stuck level sensor giving a false reading
- A partially blocked outlet valve making the tank feel fuller than it is
Rough UK cost
No cost to empty at most sites; sensor or valve repairs run £30 - £120.