How to Fill a Water Brush Pen

Waterbrush pens are unique in that they don’t include handles that are made out of plastic or wood. Instead, they include a water reservoir that works with caps and screws to keep it contained when the pen isn’t being used. 

When using these brushes, the water is gradually released from the reservoir and into the bristles. As a result, the bristles stay moist enough so that you can continue painting without having to reapply water or paint as frequently as other brushes.

If you’re new to using water brush pens and want to learn more about how to fill them with water and how to use them, check out the post below. 

Filling a Water Brush Pen

  • Start by holding the pen in a container of water or under a running tap. 
  • The running water or the pen being submerged in water will refill the reservoir. 
  • Once it’s full, you’re ready to use the pen!

Using Water Brushes

  • When using a water brush pen, the bristles shouldn’t be dripping with water. Instead, they should just be damp.
  • If you find that you want to increase the amount of water in the bristles whilst painting, you can simply squeeze the water reservoir. The more you squeeze, the damper the bristles will become. 
  • This can be great if you’re looking to add lighter colors and shades to your work. 
  • Depending on the brand that you’re using, the amount of time it takes for the water to moisten the bristles after squeezing the reservoir will vary. 
  • To prevent excess water and drops spoiling your page, be sure to continue moving the brush across the page whilst squeezing the water reservoir at the same time. 
  • This will prevent the water from the bristles from pooling in one area and causing small puddles in your work.
  • At the start, finding the right balance of pressure and time when moistening the brushes can be tricky.
  • If you accidentally squeeze the water barrel for too long and too hard, use a clean cloth or paper towel to gently soak up the excess liquid before continuing with your painting. 

Using Brush Pens for a Watercolor Painting

Many artists enjoy using brush pens for watercolor paintings. This is because the water inside of the brushes means that you don’t have to keep a cup of water nearby to keep dipping the brush into. 

Therefore, artists who are travelling enjoy using water brush pens. It means that they don’t need to keep additional cups with them. Instead, they can simply fill up the water reservoir, add the paint and start on their work. 

Simply touching the wet brush against dry paint is enough to reactivate the paint to be used for watercolor paintings. 

If you want more vibrancy from a color, simply squeeze the water reservoir to add more moisture to the paint until you achieve the type of consistency that you desire. 

Artists notice that synthetic bristles don’t retain as much paint. Therefore, if you’re using these types of brushes, be prepared to dip them into the paint more frequently. 

Flat Brush Method

You can use a water brush pen to make a flat wash effect, similar to how artists use standard watercolor brushes. 

Dip the brush into the paint like normal and hold it at more of a flat angle against the page. This flat brush method can create thicker lines in your artwork. Be sure not to squeeze the water reservoir whilst practising the flat brush method as it can make it seem too faint. 

Also read: How to Refill Alcohol Markers


After reading through our post on how to fill water brush pens, we hope that you’re feeling more confident about the process. Be sure to follow the steps mentioned above to properly fill and use your water brush pens to the best of your abilities.


What’s the best brush tip pen for blending?

Tombow dual brush pens are excellent for blending watercolor paint.

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Written By Adam Rushton

Adam has made a name for himself in the illustration industry and is a passionate blogger and writer on the subject of art, illustration and graphic design.

His artwork has been featured in countless publications and used for very well-known media projects. As a professional illustrator for over 20 years, Adams media outlets, a wealth of knowledge, and experience enable him to consult and advise artists and illustrators in this country (from York and Manchester to Southampton and London) and all over the world.