ARTICLE: 10 and 20 Gallon Galley Grey Water Tanks Explained

Last updated: November 3, 2026

What Is a GoCode Galley Grey Water Tank and How Does It Mount?

The GoCode 10 and 20 gallon galley grey water tanks are made for static mounting inside a cabinet, not for pulling in and out like a jerry can. The base slopes toward a 1 1/2" fitting at the bottom, so you can drain the tank straight through the floor of your rig. You get 10 to 20 gallons of grey water capacity with minimal installation work.

Why Choose a Galley Grey Tank

If you need a grey tank but don’t want to mount anything off the bottom of your vehicle, this is the option. It sits in your cabinet and drains through the floor. Unlike a portable jerry can, it’s meant to stay put, so your cabinet walls should fit snugly against three sides of the tank.

Sloped Base and Bottom Drain

The bottom of the tank slopes in toward a 1 1/2" fitting, so water collects at the drain. This is what makes the tank drain well.

How the Bottom Drain Works

To use the drain:

  1. Drill out the 1 1/2" fitting on the bottom of the tank with a hole saw.

  2. Mark and drill through your subfloor and floor. Check first that nothing is underneath, then drill the hole out to 2 1/2".

  3. Treat the edges of the hole.

  4. Mount a ball valve, or another way to drain the tank.

If you’d like the valve to be easier to reach, you can add a 90 degree fitting to turn the drain toward the edge of your vehicle and put the ball valve on that. With this setup the tank sits flat.

Fittings on the Top of the Tank

The top has three fittings:

  • (x2) 1 1/2" NPT fittings

  • (x1) 1/2" NPT fitting

Luke’s suggested uses are a simple barb fitting for the inlet, a level sensor (KUS Sensor), and a vent (1/2").

Key Takeaways

  • Made for static mounting in a cabinet, not for removing.

  • Available in 10 and 20 gallon sizes.

  • The base slopes toward a 1 1/2" fitting at the bottom for draining.

  • Drill the floor to 2 1/2" after checking underneath, then add a ball valve.

  • Add a 90 fitting if you want the valve closer to the edge of the vehicle.

  • The top has two 1 1/2" MPT fittings and one 1/2" MPT fitting.

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