OEM replacement lip seal that creates the water-tight barrier between the cassette toilet upper body and waste tank. 4-5/16" diameter rubber seal. Prevents leaks and odors between the bowl and cassette. For Thetford cassette toilets manufactured after June 15, 2000 only. Previously known as Thetford part number 23721.
The Thetford 50192 is the OEM replacement lip seal for Thetford cassette toilets — the 110mm rubber seal that sits between the upper toilet body and the cassette waste tank, creating the water-tight barrier that keeps waste and odors locked in the tank and prevents leakage into the cassette bay housing. Previously known as Thetford part number 23721, this is the same OEM seal under an updated part number.
Over time the lip seal degrades from exposure to waste chemicals, cleaning products, and repeated cassette removal and reinsertion cycles — resulting in leaks, odors escaping from the cassette bay, or water not holding in the bowl properly. Replacing the lip seal is a straightforward DIY service task that restores full toilet performance without requiring professional repair. Instructions are included with the seal.
This seal is for toilets manufactured after June 15, 2000 only. A different seal is required for pre-June 2000 models.
• 1x Thetford 50192 lip seal (110mm) • Installation instructions Pre-June 2000 lip seal (different part): • Contact Thetford or your RV parts supplier for the correct pre-2000 seal number — it is not interchangeable with this one Related cassette toilet maintenance parts: • Thetford Seal Lubricant — recommended at each cassette removal to extend seal life • Thetford Aqua Kem — cassette tank treatment
Replace the lip seal when you notice any of the following: • Water in the toilet bowl slowly drains into the cassette bay when the slide valve is closed • Sewer odors escaping from the cassette bay or around the toilet base • Visible cracking, hardening, or deformation of the rubber seal • Cassette becomes difficult to slide in or out smoothly Preventive maintenance tip: Apply Thetford seal lubricant each time the cassette is removed — it extends seal life significantly and prevents premature drying and cracking.
The 50192/23721 is designed specifically for Thetford cassette toilets manufactured after June 15, 2000. Pre-June 2000 models use a different lip seal with slightly different dimensions — the two are not interchangeable. Check your toilet's manufacturing date (printed on a label on the toilet body) before ordering. Ordering the wrong generation seal will result in an improper fit and continued leaking.