Thetford Lip seal for Thetford Toilets (23721)

Name: Thetford Lip seal for Thetford Toilets (23721)
Brand: Thetford
SKU: 229428
Price: 12.95 GBP
Availability: InStock
Rating: 4.94 (136 reviews)

Product Ref: 229428
Thetford Code : 23721

£12.95(inc VAT) £16.99Product Ref: 229428
Thetford Code : 23721

(4.95/5) Read Reviews - Click Here (147 reviews)

11 buyers of this product rated us 4 or 5 stars on Trustpilot

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Product Description

Cassette lip seal suit Late Thetford toilets. This is the large seal that fits on the top of the cassette tank.

Suitable for the following Thetford toilets produced after 15 June 2000.

Thetford C2
Thetford C3
Thetford C4
Thetford C200
Thetford C400

Thetford part number 23721.

EAN-13 : 8710315549812

3 FAQs on the Thetford Lip seal for Thetford Toilets (23721)

I have a 2000 swift caravan with a swivel toilet I need a new top seal is a post 2000 one going to fit

Yes it is.

Hi Tom Last year I purchased my Bailey caravan and have a problem with the c200cs cassette toilet. With the cassette blade closed fluid in the bowl leaks slowly into the cassette housing. I changed the lip seal but still have the same problem. The lip seal I purchased was for the pre-2000 model as I thought this would be right, but am now wondering if the previous owner changed the cassette to the later model. Is there a way I can tell the difference between the 2 cassettes. Thanks Bryn

The seal that you should have for this toilet is our part 229428 Thetford part 23721, If you have purchased the pre 2000 seal then you have the incorrect seal.

I have a Thetford 200 plunger flush toilet pink solution appears too leak very slightly around the joints of the holding tank

If you are referring to the waste holding tank then it is very unlikely that the joints are leaking. It is more likely that the lip seal at the top of the tank is worn which will allow a small amount of pink liquid to run down the outside of the tank and end up at the tank joint area. first thing is to replace the seal, our ref. 129428.

Reviews

147 Customer Reviews on Thetford Lip seal for Thetford Toilets (23721)

Thetford Spares

by Michael Todd (13 Apr 2026)

(5/5)

Found items which I was looking for (ie Thetford C200 Cassette)

This Seems To Be Correct

by Iain (11 Sep 2025)

(4/5)

This is "for toilets made after June 2000". Mine was made in late 1998 but nevertheless it fits correctly. I last replaced this seal five and a half years ago, and it has just started leaking a little. Perhaps if I had regularly applied the seal lubricant (not included) it would have lasted longer

Thetford Lip Seal

by William Ross (29 Jul 2025)

(5/5)

Ordered replacement seal which was delivered timeously very satisfactory transaction.

THETFORD LIP SEAL FOR THETFORD TOILETS (23721)

by Dave Morris (15 Jul 2025)

(5/5)

Genuine replacement seal. Works well and has fixed the leak on my toilet cassette. It’s advisable to use seal lubricant when installing the seal. Straight forward to fit with plenty of videos on YouTube. The only down side is I think these seals always fail because the seal is permanently compressed when the cassette is in its housing. I’m considering removing the cassette during the winter months and opening up both sides of the seal so it’s not permanently under compression. Hopefully this may extend the life.

Thetford Wc

by g davey (09 Jun 2025)

(5/5)

great service - good product

Very good website with the required…

by alan vallis (03 Jun 2025)

(5/5)

Very good website with the required info to ensure I ordered the correct parts for my Thetford toilet. Parts were delivered quickly and were well packaged.

Just The Job!

by Adrian Cross (23 Apr 2025)

(5/5)

Exchange part!
Perfect!

Fits As It Should

by Sgt. Oddball (11 Aug 2024)

(4/5)

Thetford lip seal for toilet, part no 33721. Arrived from luesureshopdirect in good time, and is a perfect fit. This is for the later model of Thetford cassette toilets, being slightly thinner than the old ones. Check which model you have (it goes by year) before you buy.

Easy to fit, 8 screws, a clean, rescrew, job done. It's actually surprising how these seals wear, you'll see when you compare the old with the new.

No more leaks when carrying!

Excellent Service From This Company

by Mike Smith (27 Feb 2024)

(5/5)

As with previous orders, an excellent service from this company. After ordering, I realised that I had a voucher and so emailed them asking how I could use the voucher. They helped me cancel the original order, reorder using the voucher and then refunded VAT (I live in Jersey). Cost of p&p also extremely reasonable. Very helpful, prompt and friendly service.

Maintenance

by Mr Anthony Buttling (15 Jan 2024)

(5/5)

The price and delivery was excellent after the xmas break, the cassette was leaking however now it does not, 30minute job max, enough said really not a pleasant job but essential

Cassette Service

by Jim Taylor (16 Oct 2023)

(5/5)

Thought it was time for a service and clean up for the cassette.
Watched a few videos on how to change the seals, seems straightforward.
New seal and blade after I soaked the cassette over night.
Good as new and cheaper than replacing the cassette.
Thetford parts and chemicals used, all came apart as per the video and went back together perfectly.

In Stock And Fast Delivsry

by Tony King (10 Oct 2023)

(5/5)

Goods in stock, good price, easy to order, fast delivery.

Great service

by James Taylor (09 Oct 2023)

(5/5)

Great service, all the bits arrived on time and as described. Well packed.

Had what I wanted

by Derek Horton (04 Sep 2023)

(5/5)

Had what I wanted, delivered PDQ and all at an acceptable price. What's not to like.

Good Delivery

by Mr Bulpett (26 May 2023)

(5/5)

Package arrived a day early on Sunday .

Thetford Cassette Toilet Lip Seal

by Jack Ditchburn (06 May 2023)

(5/5)

Does what it says on the tin.
Very prompt delivery service.
Would recommend the product and the company.

Quick And Easy.

by James Floyd (18 Jan 2023)

(5/5)

Quick and easy replacement and definitely improves the fit.

Refurbishment

by Wales (13 Sep 2022)

(5/5)

Excellent quality, sorted leaks

Toilet Seel

by Mr James (25 Aug 2022)

(4/5)

Was delivered as soon as in stock

Easy & Efficient

by Clay (24 May 2022)

(5/5)

I found all the items I needed, ordering was straightforward and the goods arrived on time and well packaged. What more could anyone want. Thank you for an excellent service.

Videos

Exploded Diagrams

Thetford C200 waste-holding tank with wheels and handle

Thetford C200 waste-holding tank

Thetford C2-C3-C4 holdings with tank

Thetford C2 - C3 - C4 waste-holding tank

Thetford C500 waste-holding tank

Thetford C220 Waste holding tank

Thetford C250 - C260 waste-holding tank

Thetford C400 waste-holding tank

Instructions

Delivery Options

Returning an Item

If you’ve changed your mind about keeping your purchase, please return it in its original condition with proof of purchase and we’ll exchange or refund it. Unless faulty, this should be within 100 days of receiving your order. By original condition, we’d expect this to mean that you’ve kept packaging and labels, and that the item is undamaged and unused.

For further information of how to return your item, please visit the "Returning an Unwanted/Faulty/Damaged Item" section on our Help Page.

Did you know we have been established and have been in the caravan and motorhome industry for over 50 years?