Rocket filter for the water tank – the strainer that protects the pump
Right at the bottom of the water tank, a small strainer sits on the intake hose. It's the first component your water passes through, and it holds back anything that doesn't belong in the tank: limescale flakes from refilling, fibres from the cleaning cloth, occasionally a coffee crumb that fell in while you were handling things.
You only notice it's there once it's clogged. Then the pump struggles, gets louder, the extraction comes out haltingly, and in the worst case it draws in air. The filter is the cheapest part in the entire water path – and the one most often overlooked, because it sits under water.
Clean and descale first, then replace
A tank filter is almost always just clogged, not defective. Take it out, rinse it under running water and, if there's limescale, soak it briefly in a descaler solution. You'll find suitable products under Machine and grinder cleaning, for example the descaler for E61 and BZ groups or the descaling pads for the water tank. Only if the mesh is torn, deformed or stays clogged despite cleaning do you need a new one.
When it's due
The pump gets louder or audibly struggles. The extraction comes out haltingly or the machine draws air. The strainer can no longer be rinsed clear. The mesh is torn or an edge has broken off. Or, after years, the filter is simply encrusted and can no longer be cleaned properly.
At a glance
| Type |
Intake filter, strainer |
| Installation location |
Water tank, on the intake hose |
| Fits |
Rocket Premium Plus and Evoluzione, according to the manufacturer's information for number C439900695 |
| Scope of delivery |
1 filter |
| Part number |
C439900695 |
| Brand |
Rocket |
Who it's for
For anyone who runs their Rocket from the tank and wants to keep the water path in good order – this is one of the few spare parts you can reach without tools. And for service workshops that fit a fresh filter at every service.
What goes with it
In the same tank you'll find the large tank gasket, the bracket for the water tank and the tank lid including plastic insert. The valve ball for the tank venting also belongs in this corner of the machine. For an overview, see Rocket accessories and spare parts, and all spare parts are listed under Original spare parts.
The connections sit at the bottom of the tank: the coupling for the tank connection, the elbow as a push-fit connector and, for the Appartamento, the 3-way tank connection. We carry the tank itself in two versions, for the newer models and for the Giotto and Cellini in the old version, plus the water tank for the R Cinquantotto.
Workshop tip from Bern and Zurich: With every machine that comes in for service, the first thing we do is look in the tank – and surprisingly often we find the explanation for a noisy pump there. Our rhythm at the counter: empty the tank, remove and rinse the filter whenever we descale anyway. That's our routine, not a manufacturer requirement. And because fresh water does more for your coffee than any bean alone: our recommendations are Cozy Chocolate, Nutty Delight and, stronger, Very Nutty. More under Coffee beans.
No returns
Original spare parts are excluded from exchange and return. They are sourced specifically for each order and cannot be resold once they have been installed or test-fitted on a machine. So before ordering, check the model, year of manufacture and serial number of your machine – or send us a quick message and we'll clarify the fit together. Your rights in the event of defective goods remain unaffected.
Frequently asked questions
How often should I replace the tank filter?
There's no fixed interval, and we won't make one up. In practice it depends on water hardness and usage. It makes sense to take it out and inspect it every time you descale – it gets replaced when it can no longer be cleaned properly.
Do I need tools for this?
No. The filter sits in the tank on the intake hose and can be reached from above. Unplug the machine before working in the tank, and when refitting, make sure the hose is back all the way at the bottom.
Does the filter replace a water filter against limescale?
No. This strainer holds back particles; it doesn't soften anything. Against limescale, soft water or regular descaling helps – you'll find both under machine and grinder cleaning.
Does the filter also fit other Rocket models?
The number C439900695 is assigned to the Premium Plus and the Evoluzione. We have no approval for other model series. Send us the serial number and we'll check it.
Can I look at the part in one of your Showrooms?
Yes. We're in Bern at Gerberngasse 44 and in Zurich at Hagenholzstrasse 50b. Let us know shortly beforehand and we'll have the part ready.
Questions about fit? Write to us at [email protected]. We deliver across Switzerland and to Liechtenstein in 2-4 working days.
