Thetford 42141
Waste Ball Seal
Thetford 42141 is the waste ball seal for the Aqua-Magic Style II and Aqua-Magic Residence. The seal the waste ball turns against in the bottom of the bowl. It holds the water in the bowl and keeps holding tank smells out of the camper.
Which models this fits
Aqua-Magic Style II
Verified against Thetford Parts List, Aqua-Magic Style II (Rev D).
Aqua-Magic Residence
Verified against Thetford Service Kit instructions, Waste Ball Seal Kit (Form No. 42142 Rev. A).
What this does NOT fit
Aqua-Magic Style Plus. Thetford’s Style Plus parts list assigns 34120 as that model’s waste ball seal, not 42141. Some retailer listings claim one seal covers both. Thetford’s own parts lists do not.
Commonly confused with this
34120 is the waste ball seal for the Aqua-Magic Style Plus. 42141 is the one for the Style II and Residence. They are listed on separate Thetford parts lists and are not interchangeable.
How to tell which one you have
Thetford publishes a serial number location sheet showing where the sticker sits on each model. Find the sticker and read the model name off it, because Style II and Style Plus look similar but take different seals.
Is this part still current?
Yes. Thetford still lists 42141 on its current parts list dated 11/4/2025.
Where to get this part
- Check price on AmazonSold by Amazon
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Check this before you order
- Confirm your toilet is a Style II or a Residence, not a Style Plus.
- If it is a Style Plus, you need 34120 instead.
- Ignore listing titles that claim one seal fits both. Thetford lists them separately.
Before you start the job
Thetford’s own instructions say to wear protective gloves and eyewear when touching material that has been in contact with human waste, and to disinfect tools and the work surface afterwards.
Where our information comes from
We work from the manufacturer’s own documents. We have not installed this part and we do not test parts in a shop.
- Thetford Parts List, Aqua-Magic Style II (Rev D), dated 11/4/2025. Published by Thetford Corporation.
- Thetford Service Kit instructions, Waste Ball Seal Kit (Form No. 42142 Rev. A), dated 27/07/2012. Published by Thetford Corporation.
- Thetford Parts List, Aqua-Magic Style Plus (Rev E), dated 11/4/2025. Published by Thetford Corporation.
Last checked 2026-08-24.