How to Lay Out a PEX-A Water System in Your Camper Van (Step-by-Step Guide)

Designing your PEX-A water system is one of the most critical—and potentially confusing—parts of a camper van conversion. Whether you’re planning for a full indoor kitchen or a simple outdoor wash-down station, a clear layout can help you avoid costly mistakes and ensure your system works smoothly from day one.

In this guide, we’ll walk through a real-world PEX-A water system layout for a 2020 Ford Transit medium roof van. You’ll see how each component connects—from the water tank to the pump, hot water heater, faucet, and rear mixer valve—so you can confidently build your own system.

What Is PEX-A and Why Use It in a Camper Van?

PEX-A tubing is a flexible, durable material ideal for camper van plumbing. It handles both hot and cold water, resists freezing and cracking, and is easy to work with—especially in tight van spaces. With the right layout and fittings, it’s possible to build a leak-free system that lasts.

Tools & Components You’ll Need

Before starting your layout, gather the essential components:

• PEX-A tubing (hot/red and cold/blue)
• Water tank
• Water pump (max 6 ft from tank)
• Hot water heater
• PEX-A fittings (tees, elbows, adapters)
• Wash-down mixer valve (e.g., Scan Devic)
• Faucet with hot and cold lines
• Aquaor fill system
• Thread sealant
• 3/8″ to 1/2″ reducers
• Marker or drawing board for layout planning

Step-by-Step Layout of the Water System

1. Start With the Water Fill

The water fill starts at the rear Aquaor valve, which connects to a garden hose or RV water hookup. This valve includes a self-sealing spring that prevents backflow and drips—ideal for van life.

2. Routing to the Water Tank

From the Aquaor valve, the water goes through a 90° elbow and a PEX-A to ½” threaded adapter. This connects to the fill port on the top of the fresh water tank.

3. Connecting the Water Pump

From the bottom of the tank, cold water runs to the water pump. Keep this line under 6 feet in length to maintain optimal pump performance. The pump pressurizes the system and sends water to both the hot water heater and the cold water lines.

4. Cold Water Line Layout

After leaving the pump, cold water splits off:

• Branch #1 → Kitchen faucet cold side
• Branch #2 → Rear mixer valve (cold side for spray-down station)

Use PEX tees and elbows as needed to navigate around tanks, shelves, or cabinetry.

5. Hot Water Line Layout

Another line from the pump goes into the hot water heater. Heated water exits the heater and splits:

• Branch #1 → Kitchen faucet hot side
• Branch #2 → Rear mixer valve (hot side)

The Scan Devic mixer valve allows hot and cold water to mix before exiting to your rear spray-down hose.

6. Rear Mixer Valve Setup

The mixer valve accepts one cold line and one hot line. A third port outputs blended water to the exterior spray nozzle. Be sure to use correct reducers (e.g., 3/8″ to ½”) to match your hose and valve sizes.

Tips for a Successful Install

• Draw Your System First: Use color-coded markers to map hot and cold lines before cutting any tubing.
• Shorten the Distance Between Tank and Pump: The closer your pump is to the tank, the better it will function.
• Use Thread Sealant on Adapters: This ensures leak-free connections between threaded fittings and PEX.
• Label Everything: When laying out parts temporarily, label hot, cold, and return lines so you don’t mix them up later.

Sample Flow Summary

Final Thoughts

Setting up your PEX-A camper van water system can feel overwhelming at first. But once you take the time to lay it out—either on a table or with a sketch—you’ll see how each part plays a role. The key is to keep your runs short where it matters (tank to pump), use proper fittings, and plan your branches logically.

With a little patience and planning, you’ll have a professional-grade water system ready for all your van adventures.

Need more help? Drop your questions in the comments or check out our installation videos on YouTube. Happy building!