Dometic Toilet: “Cassette tank 3/4 full”
info RV toilet warning lights
What it means
On the Saneo control panel, the 'cassette tank 3/4 full' display lights to give advance warning that the waste cassette is about three-quarters full. The toilet still works; this is a prompt to plan emptying soon.
Most likely causes
- Cassette has filled to roughly three-quarters capacity most likely
- Float partially obstructed giving an early reading less common
Safe checks you can do yourself
- Plan to empty the cassette before it reaches full.
- If the reading seems premature with a known-empty cassette, check that the float moves freely (no high-pressure cleaning).
How to reset / clear Cassette tank 3/4 full
- No reset needed; the display clears after the cassette is emptied.
When to call a technician
The 3/4 or full displays behave erratically after the float and wiring are checked, indicating a sensor or panel issue.
Applies to
Dometic Saneo CS · Dometic Saneo C · Dometic Saneo B · Dometic Saneo cassette toilet series
FAQ
What does Dometic Toilet code "Cassette tank 3/4 full" mean?
On the Saneo control panel, the 'cassette tank 3/4 full' display lights to give advance warning that the waste cassette is about three-quarters full. The toilet still works; this is a prompt to plan emptying soon.
How do I reset Dometic Toilet Cassette tank 3/4 full?
No reset needed; the display clears after the cassette is emptied.
What is the most common cause of Cassette tank 3/4 full on a Dometic Toilet?
The most likely cause is cassette has filled to roughly three-quarters capacity.
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Sources
- Dometic Saneo Operating Manual — Description of control panel — item 4 'Cassette tank 3/4 full' display (Dometic GmbH)
Note: Advance-warning level indicator, not a fault. Saneo is a cassette (not macerating) toilet but uses an electric indicator panel.
● Last verified 2026-06-29 · compiled from manufacturer documentation. Codes can vary by model year — always cross-check your unit’s manual.