How to select the best pump/res combo for your water-cooled PC.

Welcome back to the Component Series. We hope to help builders both new and old to understand their options when it comes to the components in their custom water loops. In this installment we’re going to take a look at pump and reservoir combos. 


EKWB EK-Classic Pump Reservoir 160 SPC PWM, Digital RGB

A traditional tube-type pump reservoir combo unit from EKWB.


Combo Units 

We’ve already covered water cooling pumps and reservoirs in previous editions of the Component Series. Pumps are necessary parts of custom water cooling loops and reservoirs offer a number of advantages. These two components are so intrinsic to PC water cooling that manufacturers started making them together as a single unit.  

While individual pumps and reservoirs are perfectly viable options for your water cooling setup, there are a few reasons to consider a pump and reservoir combo.  


Custom PC water cooling pump reservoir combination unit 

A tank-style reservoir/combo unit from Barrow. These can be great space savers. 



Space – Given the same size reservoir, a pump/reservoir combo unit is more compact than separate parts. This is especially important with the popularity of small form-factor PCs today. 

Simplicity – Combining the pump and reservoir into a single unit simplifies installation and ensures that the pump receives coolant constantly. 

Expense – A pump/reservoir combo unit is typically less expensive than separate comparable parts. Even if those costs are equal, a combo unit requires fewer fittings


Phanteks Glacier R220 Reservoir, Copper Base 

Phanteks offers another example of the tank-style pump/reservoir combo. 


Like anything though, there are some cons to go with the pros. 



Single point of failure – If any part of a pump/reservoir combo fails, the entire unit is out of service. With separate components, replacement is less costly. This is becoming less of a factor though as more brands are offering parts for their combo units separately. 

Mounting – While mounting a pump/reservoir combo unit can be easier than mounting separate components, you’ll have fewer mounting options due to the unit’s size. Mounting two components connected by tubing offers many more choices than mounting a single larger part. This is of course less of a problem with more compact combo units. 



Pump/reservoir combos come in three distinct flavors. 


Corsair Hydro X Series XD5 RGB Pump/Reservoir Combo with RGB Adapter Cable 

A square-bodied tube reservoir combo with mount from Corsair.



Tube pump/res combos are simply tube reservoirs with a base designed to hold or mount a water pump. These are available for DDC and D5 pumps, as well as some proprietary pumps. 


Alphacool Eisball Reservoir and D5 Pump Top 

Alphacool's Eisball is a unique take on the tank-style pump/res combo. 



Tank style pump/reservoir combination units are typically flat and squared off, made to be mounted on interior faces of a PC case. The pump on these units is typically mounted on the side as they are too thin to mount a pump on the bottom like a tube reservoir. 


Monsoon Series Two D5 Premium Dual Bay Reservoir 

Dual-bay D5 pump/reservoir combo from Monsoon.



Bay style pump/reservoir combos occupy an external 5.25” drive bay. They offer the advantage of a coolant level visibility from the front of the case, and very simple mounting.  

While these are solid options, many case manufacturers are doing away with external drive bays altogether. Be sure your case has a place to put it. 



Pump Type 

Every pump/reservoir combo on the market is made to work with a specific pump. Whether it’s a DDC, a D5 or some other proprietary pump, the combo unit can only be used with an identical pump. That makes pump selection even more important than when choosing a standalone water pump. 


Custom pump reservoir unit for pc water cooling 

A custom-built D5 pump/reservoir combo unit made with Monsoon’s Modular Reservoir System. 


It’s worth noting that while pump/reservoir combo units are made to work with a specific type of water pump, they don’t all include the pump itself.  Some are available with the pump mount but leave the choice of the actual pump up to you. 

A pump/reservoir combo can help with available space, simplicity of mounting and the overall cost of your custom water cooling loop. Be sure to check the pump type that the combo unit is made to work with and your available space and you’ll find a combination unit that will work for your custom PC.