classAcustoms Class A Customs | 42 Gallon RV Concession Fresh Water Tank with Plumbing Kit & 12 Volt Water Pump | T-4200-BPK-PUMP

Why I picked this 42‑gallon kit

I needed a compact, food‑grade fresh water setup for a small trailer build that could be mounted in odd spaces and run off 12 volts. The Class A Customs 42‑gallon kit checked the right boxes: NSF‑approved polyethylene tank, built‑in ports, a basic plumbing kit to get started, and an on‑demand 12 V pump rated at 3.0 GPM and 45 PSI. The ability to rotate the tank to suit the space was the clincher.

After several weeks of installation, testing, and actual use, here’s how it performed and what I’d change.

Build quality and tank design

The tank itself is the star of the kit. Wall thickness is substantial for the class, and the molded body feels uniform without soft spots. I weighed the decision to mount it on its long side versus tall; rotating it made planning around my frame members much easier, which is a big deal in tight conversions.

A few practical notes on the integrated fittings:
- The two 1.5" female NPT ports come sealed with a thin membrane from the factory. You must cut that out cleanly with a razor before using them.
- The two 0.5" female NPT ports are open for vent/draw.
- Use plastic NPT fittings, not metal, to avoid chewing up the threads. A potable‑water thread sealant or PTFE tape used sparingly works well.
- Don’t over‑torque; hand‑tight plus a quarter turn is plenty on plastic.

This is a non‑pressurized tank and needs to breathe. I ran a dedicated 1/2" vent line up high with a gentle loop and bug screen. If you’re new to RV water systems: never connect a pressurized city water hose directly to the tank. Use a gravity fill dish on the 1.5" port, and keep the vent open during filling and use.

Installation experience

The included plumbing hardware is genuinely helpful for a first pass: barb adapters, clamps, and two short lengths of hose (5' each) for fill and vent/draw. In practice, I needed additional hose, a proper gravity fill dish, a ball valve for the drain, and a few more adapters to interface with PEX. Treat this kit as a starter set rather than the entire bill of materials.

Mounting the tank:
- Plan for roughly 350+ pounds when full (42 gallons x ~8.34 lb/gal), plus tank and hardware.
- Support the tank fully across its footprint; don’t rely on two narrow crossbars.
- Use wide straps with padding to prevent abrasion and avoid overtightening.
- Allow space to access fittings and for inspection.

I placed a thin sheet of HDPE under the tank to reduce chafe and used rubber‑isolated clamps on the lines. The footprint and dimensions (27.5" x 15.25" x 22.5") were accurate enough for planning; tolerances are typical rotational‑molded variances.

Pump performance and plumbing behavior

The included 12 V on‑demand pump is rated 3.0 GPM with a 45 PSI shutoff, drawing 4 A nominal (8 A max). Wired with 12 AWG and a 10 A fuse on a 12 V bus, it primed quickly and delivered flow close to spec on short runs—my kitchen faucet saw 2.6–2.8 GPM depending on filter load, with shutoff cycling as expected. On a low‑flow shower head (~1.5 GPM), pressure felt comfortable, not “city water crisp,” but more than adequate for handwashing, dish duty, and a short shower.

Noise is typical diaphragm pump thrum. Mounting on rubber feet and adding a short length of soft hose on the inlet/outlet before transitioning to rigid PEX cut the resonance substantially. I also added a small inline strainer on the suction side—highly recommended to protect the pump from plastic shavings and installation debris.

A few operational observations:
- Without an accumulator tank, the pump cycles more frequently at low flows. If you care about smoothness and reduced noise, add a small accumulator.
- Flow drops if your suction run is long or has tight bends; keep the pump close to the tank and minimize restrictions.
- Prime held well between trips; no leaks at fittings after a weeklong test.

I did experience one hiccup: early on, the pump tripped its internal switch intermittently. In my case, a bit of trapped air and a partially clogged strainer were the culprits. Once bled and cleaned, it ran reliably. I can’t vouch for long‑term longevity yet; it behaves like an entry‑level RV pump—functional but not premium.

Water quality and sanitation

Out of the box, the tank had a faint plastic smell, which disappeared after a standard sanitization cycle. My routine:
- Mix about 1/4 cup unscented household bleach per 15 gallons of water.
- Fill the tank with the solution, run it through all lines until you smell bleach, and let it sit for 4–12 hours.
- Drain completely, then refill with clean water and flush until the odor is gone.

Taste after sanitization was neutral. The tank material is NSF‑approved for potable water, which gave me confidence for food‑service use. If your water sits for weeks, flush and refresh—standard good practice.

Real‑world use

For a small trailer and weekend trips, 42 gallons is a sweet spot: enough capacity to avoid daily refills while keeping weight manageable. Using a mix of dish washing, handwashing, and two quick showers, I averaged three days before needing to top off. The gravity fill with a 1.5" hose makes refills predictable—no burping or blowback when the vent is properly routed.

The kit’s 5' hoses are helpful for initial plumbing, but most installations will need more length. I replaced the supplied clamps with quality stainless worm‑drives and added a dedicated drain valve to one of the 1.5" ports. Having two large ports is handy: one for fill/dish, one for drain/cleanout.

What I’d improve

• Pump options: The included pump works, but it’s basic. Offering an accumulator bundle or a higher‑end pump option would better match the tank’s quality. If your build depends on daily, heavy use, plan for a spare pump or consider upgrading from the start.
• Hose lengths: Ten feet each for fill and vent would suit more installations.
• Documentation: A simple diagram showing recommended orientation for fill, vent, draw, and drain would save installers a bit of guesswork, especially the note about the 1.5" port membranes.

Tips for a better install

• Always vent the tank. A 1/2" vent line routed high with a screen is cheap insurance.
• Use plastic NPT fittings and avoid overtightening.
• Place the pump below the tank waterline if possible for easier priming.
• Add an inlet strainer and consider an accumulator to reduce cycling and noise.
• Fuse the pump close to the power source; 10 A is appropriate for this unit.
• Support the tank across its entire base, not just with straps.
• If connecting to any pressurized source, isolate the tank with a gravity fill—don’t tee city water into the tank.

Durability outlook

The tank should outlast most of the build around it—rotationally molded polyethylene is tough, and the wall thickness inspires confidence. The pump, being the only moving part, is where I’d expect maintenance. It’s serviceable and easy to replace, which is the reality of small 12 V diaphragm pumps. Keep a spare on hand if continuous uptime matters to you.

The bottom line

The 42‑gallon kit delivers real value for small RVs, skoolies, and concessions: a well‑made potable water tank with flexible mounting, the core fittings to get started, and a 12 V pump that’s capable of supporting sinks and low‑flow showers. Installation is straightforward if you’ve done RV plumbing before, and perfectly manageable for a careful DIYer who reads up on venting and gravity fill best practices.

Would I recommend it? Yes—with a caveat. I recommend this kit for builders who want a solid, NSF‑approved tank and a functional pump at a good price, and who are comfortable refining the system with an accumulator, strainer, and a few extra fittings. If you need premium, whisper‑quiet performance or mission‑critical uptime, budget for a higher‑end pump or carry a spare. The tank itself is excellent; the rest of the kit gets you most of the way there, and with a few smart tweaks, it becomes a dependable fresh water system.