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Quick answer: To use a water brush pen, unscrew the barrel, fill it about two-thirds with clean water, and screw it back on. Squeeze the barrel gently until the tip is damp, touch the tip to your watercolor, pencil or marker color, and paint. To clean or change colors, squeeze a little water out while wiping the tip on a paper towel until it runs clear.
Learning how to use water brush pens takes about ten minutes, and once it clicks you can paint anywhere without a water jar. The pen does the job of a brush and a rinse cup in one: the barrel stores water, and a light squeeze pushes it into the synthetic tip.
This guide covers filling and opening the pen, controlling water, and using a water brush with watercolor paints, watercolor pencils, watercolor markers and ink. If you have not bought one yet, see our comparison of the best water brush pens first.
What Are Water Brush Pens Used For?
A water brush pen is a refillable plastic barrel with a nylon brush tip. Water flows from the barrel to the tip when you squeeze, so the brush stays wet without dipping. That makes it useful for:
- Travel and urban sketching with a small pan watercolor set
- Activating watercolor pencils and water-soluble crayons
- Blending water-based markers into soft gradients
- Brush lettering and ink drawing when filled with ink
- Quick color studies and journaling, where setup time matters
How to Use Water Brush Pens: Step by Step
Step 1: Open the pen
If you are wondering how to open a water brush pen, the barrel simply unscrews from the section that holds the tip. Pull off the cap, hold the tip section in one hand and the barrel in the other, and twist. Some new pens are screwed on firmly, so grip the barrel near the joint rather than at the end.
Step 2: Fill the barrel
There are three easy ways to fill a water brush pen:
- Under the tap: Hold the open barrel under a gentle stream of clean water.
- Submerge and squeeze: Squeeze the empty barrel, dip its open end into a cup of water, then release. The barrel draws water in as it springs back. Repeat once or twice.
- Pour or pipette: Use a small dropper or bottle when you are outdoors.
Fill to roughly two-thirds, not to the brim. Budget brands like UPINS and Junreox state this directly in their instructions, and the air gap makes leaks and sudden floods less likely. Screw the barrel back on firmly so water cannot seep out at the joint.
Step 3: Prime the tip
Hold the pen tip-down over a paper towel and give the barrel a gentle squeeze. On a brand-new pen it can take a few squeezes, or a firmer squeeze, before water reaches the bristles. Junreox mentions this in its listing, and it is normal. Stop as soon as the tip looks evenly damp.
Step 4: Pick up paint
Touch the damp tip to a watercolor pan and swirl lightly. The water in the tip lifts the pigment. For more intense color, rub longer or give a tiny squeeze while you are on the pan. For a lighter tint, pick up less paint and add a little more water.
Step 5: Paint and control the water
Paint with little or no squeezing for dry, controlled strokes. Squeeze lightly while painting when you want a wetter wash or a smooth gradient. The key skill is the squeeze: small and frequent is better than one big push, which dumps water and creates blooms.
Step 6: Clean the tip between colors
To change color, squeeze the barrel gently while wiping the tip on a paper towel or rag. Keep going until the towel shows clean water. This takes a few seconds and replaces rinsing in a cup.
Step 7: Store it properly
After painting, clean the tip until it runs clear, replace the cap and store the pen tip-up or flat. If you are flying, empty the barrel first; pressure changes can push water out. For longer storage, empty and air-dry the barrel.
How to Use Water Brush Pens for Beginners: Practice Drills
Spend one page on these drills before your first painting:
- Pressure lines: Draw lines pressing lightly, then harder, to see how thin and thick strokes change with tip pressure.
- Squeeze control: Paint a square while squeezing once at the start only, then another while squeezing constantly. Compare how wet each one is.
- Gradient wash: Start with strong color, then keep painting while squeezing a little more water to fade it out.
- Lifting: Paint a patch, then touch a clean, damp tip to it and blot with a towel to lift color.
Use watercolor or mixed-media paper. Thin printer paper buckles quickly even with the modest water a water brush releases. Our guide to the best watercolor paper for artists covers good options.
How to Use a Water Brush Pen for Watercolor
Pan watercolors are the classic partner for water brushes. Before you start, give each pan you plan to use a few drops of water from the pen to soften the paint.
- Work light to dark, just as with a regular brush.
- Use a large round or flat tip for washes and a small round for details.
- Mix colors on the lid or a palette by depositing one color, cleaning the tip on a towel, then adding the second.
- For wet-in-wet, squeeze to wet an area with clean water first, then touch color into it.
Water brushes release less water than a fully loaded traditional brush, so very large, even washes are harder. For a full breakdown, see our comparison of a water brush pen vs a regular brush.
How to Use Watercolor Pencils With a Water Brush
Water brushes and watercolor pencils are a natural pair. There are three common methods:
- Draw then activate: Color your drawing dry, then run the damp water brush over it. The pigment dissolves into a wash. Lighter pencil pressure gives a softer, more even result.
- Lift from the pencil tip: Touch the wet brush directly to the pencil lead to pick up color, then paint with it like a tiny watercolor pan.
- Scribble palette: Scribble a patch of pencil on scrap paper and use it as a palette.
Clean the brush on a towel between colors so you do not drag one pigment into another. If you are choosing pencils, see our guide to the best watercolor pencils.
How to Use Water Brush Pens With Watercolor Markers
Water-based markers and brush pens blend well with a water brush:
- Pull color from the line: Draw a marker line, then drag the damp water brush along one edge to soften it into a gradient.
- Palette method: Scribble marker onto a plastic sheet or smooth palette and pick it up with the water brush to paint lighter tints.
- Direct transfer: Touch the marker tip to the water brush tip to load color, then paint.
This only works with water-based markers. Alcohol markers do not reactivate with water.
How to Use a Water Brush Pen With Ink
You can fill the barrel with ink instead of water to make a refillable brush pen for lettering and drawing. The Zebra, Mr. Pen and UPINS listings all mention filling with ink.
- Use a dedicated pen for ink so your watercolor pen stays clean.
- Diluted water-based ink flows more easily than thick ink.
- Flush the pen with clean water when you finish; dried ink inside the barrel or tip can block water flow.
- You can also keep water in the barrel and dip the tip in ink for washes and soft gray tones.
The Junreox 12-piece set includes duplicate tips, which makes it easy to keep separate pens for ink and water.
Which Water Brush Pen Should a Beginner Start With?
For a first water brush pen set, you mainly need a small round, a large round and a flat. The Zebra Pen Water Brush 3-pack covers exactly those three shapes at a low price. If you want a long-established watercolor brand, the Pentel Aquash 4-pack is a common recommendation.
If your pen leaks, floods or will not release water at all, the fix is usually simple. Our guide to a water brush pen not working walks through each problem.
FAQs
How do you fill a water brush pen?
Unscrew the barrel from the tip section, then fill it under a tap or squeeze it and dip it in a cup of water so it draws water in as you release. Fill about two-thirds full and screw it back on tightly.
How do you open a water brush pen?
Remove the cap, hold the tip section firmly and twist the barrel counterclockwise to unscrew it. If it is stiff, grip close to the joint for better leverage.
Why is no water coming out of my new water brush pen?
New pens often need a few firm squeezes before water travels through the valve or filter into the tip. Hold the tip downward over a paper towel and squeeze several times until the bristles are damp.
Can you use a water brush pen for drawing?
Yes. Filled with ink, a water brush pen works as a refillable brush pen for drawing and lettering. Filled with water, it is used for adding washes to pencil or pen drawings.
Do you need to rinse a water brush pen in water?
No. You clean it by squeezing a little water out while wiping the tip on a paper towel until it runs clear. That is the main reason water brushes are popular for travel.
Can I use acrylic paint with a water brush pen?
Some budget listings, such as UPINS and Junreox, mention acrylics. If you try it, clean the tip immediately, because acrylic dries permanent and can ruin the bristles. Watercolor, watercolor pencils and water-based markers are the safer match.
Next Step
Fill your pen two-thirds, practice the squeeze on one test page, and then move on to a small sketch. Once you know which tip shapes you reach for most, browse the water brush pen sets we recommend to build a kit that matches the way you paint. When you are back home, our guide on how to care for watercolor brushes will help all your brushes last longer.
