Running Water, Van Style: Completing the 2025 Show Van's Water System

Okay, van lifers and DIY enthusiasts, get ready to dive deep into the heart of van comfort! Matt's back from the AVC RIG shop, and on this episode of AVC Chronicles, we're wrapping up the crucial water system in our 2025 show van. If you've been following along, you know we've already tackled the undermounted tank and basic lines. Now, it's time for the nitty-gritty: plumbing for hot and cold water to the sink, the rear shower, and integrating the hot water tank.

This isn't just about pipes and fittings; it's about bringing the comforts of home to the open road. Let's explore how we bring water to life in an AVC RIG build!

Remember how we left off with our water tank tucked neatly under the van and the main supply lines run to the pump? Well, today, we're taking those essential foundations and turning them into a fully functional, pressurized water system, complete with hot and cold running water!

The Brainstorm: Planning Your Van's Plumbing

Before any wrench is turned, precise planning is key. Our 2025 show van features:

• An IsoTemp 4.2 Slim Hot Water Tank located mid-van.

• A hot and cold shower mixer at the rear.

• A hot and cold sink in the front kitchenette.

• An internal water fill, which we'll talk more about!

We've got two main lines coming up into the van from the undermounted tank and pump: the water fill line and the freshwater supply line. Let's break down how we connected everything.

Filling Up: Secure and Smart Water Inlets

At AVC, we prefer to place our water fills inside the van doors. Why? Security. It prevents anyone from tampering with your water system. While some prefer exterior fills, we opt for peace of mind.

For this build, we're using the Aqua RV City Water Inlet. This isn't your average hose bib! Popularized by home-building expert Matt Risinger, this high-end unit features a built-in shut-off valve. This means you can disconnect your hose from a pressurized system without any spillage – much cleaner than gravity fills that can slosh around. The trade-off? You generally need pressurized water to fill. For those times you're off-grid without a spigot, a 12-volt transfer pump is your best friend for filling from a jerry can.

Our water fill line simply connects from the tank up to this Aqua inlet, a very straightforward connection.

From Flexible to Fixed: The PEX Transition

Our freshwater supply line comes from the pump and enters the van as a flexible hose. To build a robust system inside, we transition to PEX piping. We achieve this by using a barb fitting screwed into a PEX dog ear, which is then hard-mounted to the van's floor. This creates a secure and stable PEX connection from which we can branch out to all our water components.

Cold Water Distribution: Strategic Branching and Drains

From our main PEX connection, the cold water system branches out:

• To the Hot Water Tank: A "T" fitting supplies cold water directly into the IsoTemp hot water tank.

• To the Sink: The cold water line continues forward to the sink.

• To the Shower: Another "T" branches off to supply cold water to the rear shower mixer.

• High-Pressure System Drains: A critical feature for winterizing! We install "T" fittings on both the cold and hot water lines on the pressurized side of the pump. These connect to quarter-turn ball valves that drain out the bottom of the van. Combined with a simple gravity drain on the tank, this allows for quick and easy full system winterization by opening just three valves.

Isolation Valves: Peace of Mind on the Road

A lesson learned the hard way: the ability to isolate sections of your water system is invaluable. We install ball valves to isolate both the cold water side and the hot water side completely. This means if you ever have a leak or an issue with your hot water tank while out on the road, you can shut off that specific section and still have cold water for dishes or basic needs. We even put a ball valve on the cold water line leading to the shower for complete isolation.

Hot Water Highway: From Tank to Tap

The hot water journey begins at the IsoTemp tank:

• To the Shower: Hot water exits the tank, hits a "T", and heads back to the rear shower mixer. A ball valve isolates this line at the shower.

• To the Sink: The hot water line continues forward to the sink.

For connecting to the sink's faucet, we use stopcocks (those small quarter-turn valves you see under home sinks). These connect PEX A on one side and have a 3/8-inch fitting on the other for easy connection to braided steel faucet lines.

The Check Valve: Preventing Backflow Surprises

Here's a common issue we've solved: if your hot water tank is pressurized by the pump, but the pump is off, you can get hot water flowing back through your cold system when you open the cold tap. To prevent this, we install a one-way check valve on the cold water line before it enters the hot water tank. This inline PEX valve ensures water flows only in one direction, preventing any unexpected lukewarm surprises from your cold tap! These are readily available in PEX A and other PEX styles, even Sharkbite, for easy integration into existing systems.

Pressure Relief Drain: Safety First

Finally, the IsoTemp tanks have a built-in pressure relief valve – a good thing if temperatures get too high. We plumb a drain line from this valve using clear vinyl hose. Since this is a low-pressure drain, the clear hose clearly indicates its purpose when you're looking under the van.

Bringing it to Life: The Real-World System

Seeing the diagram come to life in the van is incredibly satisfying. From the Aqua water fill with its neat dust cap and braided line disappearing into the tank, to the robust nylon-to-PEX transition, every connection is designed for durability and ease of use. You can trace the cold lines branching to the shower (with its isolation valve), the hot water tank (with the crucial check valve), and the main drain. Similarly, the hot lines flow from the tank to the shower and forward to the sink, each with their strategic isolation points.

You Can Do This!

Putting a water system together might seem daunting, but it's absolutely a DIY-friendly project. We managed to plumb this system in about two hours (with all our tools and bulk fittings, of course!). If this is your first time, don't be shy – set up shop in the parking lot of your big box store. It saves countless trips inside for forgotten fittings! And remember, any extra fittings can always be returned.

Got questions about building your van's water system? Drop them in the comments below, and we'll help you out!