Thetford 31856

Seat and Cover Assembly - White

Thetford 31856 is the seat and cover assembly - white for the Aqua-Magic VI. The seat and lid, supplied together as one assembly. Thetford lists it for Aqua-Magic VI.

Which models this fits

  • Aqua-Magic VI

    Verified against Thetford Parts List, Aqua-Magic VI (Rev. E).

What this does NOT fit

Porta Potti345.Campa Potti XG. Thetford's Porta Potti345.Campa Potti XG parts list assigns 21317 to this position, not 31856.

Porta Potti345Campa Potti XG. Thetford's Porta Potti345Campa Potti XG parts list assigns 21317 to this position, not 31856.

Aqua-Magic V. Thetford's Aqua-Magic V parts list assigns 31703 to this position, not 31856.

Aria Classic. Thetford's Aria Classic parts list assigns 33384 to this position, not 31856.

Aria Deluxe. Thetford's Aria Deluxe parts list assigns 33384 to this position, not 31856.

Aria Deluxe III. Thetford's Aria Deluxe III parts list assigns 33384 to this position, not 31856.

Aqua-Magic Style Lite. Thetford's Aqua-Magic Style Lite parts list assigns 34144 to this position, not 31856.

Aqua-Magic Style Plus. Thetford's Aqua-Magic Style Plus parts list assigns 34144 to this position, not 31856.

Commonly confused with this

  • 21317

    21317 is the seat and cover assembly (cp xg) listed for Porta Potti345.Campa Potti XG and Porta Potti345Campa Potti XG. 31856 is listed for Aqua-Magic VI. They appear on separate Thetford parts lists.

  • 31703

    31703 is the seat and cover assembly - white listed for Aqua-Magic V. 31856 is listed for Aqua-Magic VI. They appear on separate Thetford parts lists.

  • 33384

    33384 is the seat and cover assembly - white listed for Aria Classic, Aria Deluxe and Aria Deluxe III. 31856 is listed for Aqua-Magic VI. They appear on separate Thetford parts lists.

  • 34144

    34144 is the seat and cover assembly - white listed for Aqua-Magic Style Lite and Aqua-Magic Style Plus. 31856 is listed for Aqua-Magic VI. They appear on separate Thetford parts lists.

How to tell which one you have

Check the model on the data plate reads Aqua-Magic VI. This is the white version; the colour is part of the number, not a finish option.

Is this part still current?

Yes. Thetford still lists 31856 on its current parts list. Earlier revisions of the Aqua-Magic Residence parts list carried this number. The current revision does not, so it is not claimed as a fit for that model.

Check this before you order

  • Confirm your toilet is a Aqua-Magic VI.
  • If it is a Porta Potti345.Campa Potti XG or a Porta Potti345Campa Potti XG, order 21317 instead.
  • If it is a Aqua-Magic V, order 31703 instead.
  • If it is a Aria Classic, Aria Deluxe or a Aria Deluxe III, order 33384 instead.
  • If it is a Aqua-Magic Style Lite or a Aqua-Magic Style Plus, order 34144 instead.
  • Check you need white — the other colours are different part numbers.
  • Ignore listing titles that claim one part covers several models unless the manufacturer's parts lists agree.

Current marketplace inventory

Listings from eBay

We verified the part above from manufacturer documents. The listings below are current eBay inventory, and eBay sellers set their own titles, prices and shipping.

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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.

Last checked 2026-08-29.