Thetford C220 cassette cap with measuring cup - blue pour-out spout screw cap for dosing toilet fluid, original spare part 20096785
- Original Thetford cap with measuring cup 20096785 for C220 series cassettes. It screws onto the pour-out spout, and the measuring cup inside helps you dose the waste-holding tank fluid.
The cassette spout cap is easy to lose at the disposal point, and a cracked or worn thread means the tank is no longer closed properly. This original Thetford cap with part number 20096785 fits the cassettes of C220 series toilets. It is more than a plain plug: under the screw cap there is a measuring cup, so the same part closes the spout and measures the waste-holding tank fluid. The blue cap has a ribbed edge that is easy to grip even with wet hands. The cap fits both versions of the C220 cassette, standard and outside vent, as both have the same pour-out spout.

Key features
- original Thetford part, part number 20096785
- for C220 series cassette toilet cassettes
- fits the standard and the outside vent cassette
- screw cap that closes the pour-out spout
- measuring cup for dosing waste-holding tank fluid
- blue cap with ribbed edge
- weight 82 g
What the cap with measuring cup does
The cap closes the pour-out spout you use to empty the cassette. With the spout turned back into place and the cap screwed on, the contents of the tank do not leak while driving or when you take the cassette out. The measuring cup under the cap comes in handy after each emptying. You unscrew the cap, measure the waste-holding tank fluid in it in the amount given on the product label and pour it in through the spout. You need no separate cup and you do not pour the fluid through the bowl.
Which toilets it fits
The cap fits the cassettes of Thetford C220 series cassette toilets. This series includes the models C223-S, C223-CS, C223-CW, C224-CW and C222-SWE, among others. It fits both the standard cassette with automatic vent and the cassette with outside vent. C200, C250, C260, C400 and C500 series toilets use different caps with measuring cups, so this part is not meant for them. You will find the toilet model on the data badge underneath the cassette.
When to replace the cap
- the cap got lost while emptying the cassette
- the thread of the cap is cracked or worn and the cap does not hold securely
- the cap is cracked or deformed
- the marks on the measuring cup are hard to read and dosing becomes difficult
- you want a spare cap for the trip
How to use the cap with measuring cup
- After emptying and rinsing the cassette, stand it upright and turn the spout upwards.
- Unscrew the cap and turn it over with the measuring cup facing up.
- Measure the waste-holding tank fluid in the cup in the amount given on the product label.
- Pour the fluid into the cassette through the spout.
- Screw the cap back on and turn the spout back into place.
- Slide the cassette into the toilet.
Replacement and care
- Empty and rinse the cassette before replacing the cap.
- Check that the spout thread is clean and undamaged before you screw on the new cap.
- Tighten the cap by hand, without tools, so you do not damage the thread.
- Rinse the measuring cup with clean water after use.
- Do not use harsh cleaners or solvents that can damage the plastic.
Thetford video on replacing the measuring cup
In this video the manufacturer shows how to replace the cap with measuring cup on the C220 toilet cassette.
Matching Thetford parts and accessories
- Thetford C220 cassette, standard version - the complete tank with automatic vent
- Thetford C220 cassette with outside vent - the complete tank for toilets with outside vent
- Thetford C223-CS cassette toilet - C220 series toilet with an 18 l cassette
- Thetford C224-CW cassette toilet - C220 series toilet with its own flush water tank
- Float arm for the Thetford C220 cassette - part of the level indicator
- Sliding knob for the Thetford C220 cassette - replacement for the part that opens the blade
- Thetford cassette carry bag - for storing and carrying the cassette
- Thetford Aqua Kem Blue Concentrated 780 ml - waste-holding tank fluid
- Thetford Seal Lubricant - spray for seal care
Technical data
| Parameter | Value |
|---|---|
| Type | pour-out spout cap with measuring cup for a toilet cassette, spare part |
| Brand | Thetford |
| Fits | cassettes of Thetford C220 series cassette toilets |
| Cassette versions | standard and outside vent |
| Function | closing the tank spout and measuring the waste-holding tank fluid |
| Colour | blue cap, grey measuring cup |
| Weight | 82 g |
| Manufacturer part number | 20096785 |
| EAN | 8710315023305 |
Frequently asked questions
Does this cap fit my cassette?
It fits the cassettes of Thetford C220 series toilets, for example C223-S, C223-CS, C223-CW and C224-CW, both in the standard and the outside vent version. You will find the toilet model on the data badge underneath the cassette.
How much fluid should I measure?
As much as the fluid manufacturer gives on the label. The amount depends on the type of fluid and the cassette capacity.
Does it fit a C250 or C260 toilet?
No. The C250 and C260 toilets use a different cap with measuring cup. This part is meant for C220 series cassettes.
Is toilet fluid included?
No. You get the cap with measuring cup only. You will find waste-holding tank fluid in the links above.
Manufacturer
Thetford B.V., Nijverheidsweg 29, 4879 AP Etten-Leur, The Netherlands.





