---
product_id: 110463112
title: "Class A Customs 40 Gallon RV Waste Black Water Holding Tank WT-4000"
brand: "classacustoms"
price: "S$694"
currency: SGD
in_stock: true
url: https://www.desertcart.sg/products/110463112-class-a-customs-40-gallon-rv-waste-black-water-holding
store_origin: SG
region: Singapore
---

# 3” ABS Fixed Outlet 40 Gallon Capacity Made in USA MDPE Resin Class A Customs 40 Gallon RV Waste Black Water Holding Tank WT-4000

**Brand:** classacustoms
**Price:** S$694
**Availability:** ✅ In Stock

## Summary

> 🚐 Own the road with confidence—waste management made effortless!

## Quick Answers

- **What is this?** Class A Customs 40 Gallon RV Waste Black Water Holding Tank WT-4000 by classacustoms
- **How much does it cost?** S$694 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.sg](https://www.desertcart.sg/products/110463112-class-a-customs-40-gallon-rv-waste-black-water-holding)

## Best For

- classacustoms enthusiasts

## Why This Product

- Trusted classacustoms brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Lightweight Yet Robust:** Easy to handle during installation but built to withstand heavy loads when full
- • **Precision 3” ABS Outlet:** Engineered for secure waste flow—just add your custom piping
- • **Massive 40-Gallon Capacity:** Perfect for extended RV trips without frequent dumps
- • **Premium USA-Made MDPE Resin:** Durable, seamless one-piece construction resists cracks and leaks
- • **Customizable Inlet & Vent Placement:** Tailor installation to your RV setup for optimal venting and performance

## Overview

The Class A Customs WT-4000 is a 40-gallon black water holding tank crafted in the USA from durable Medium Density Polyethylene resin. Designed exclusively for waste and gray water use in RVs, campers, trailers, and tiny homes, it features a fixed 3” ABS female outlet and requires user-installed inlet and vent fittings. Its seamless, rectangular design ensures leak resistance and longevity, making it an essential upgrade for any serious road warrior.

## Description

RV Waste Water Holding Tank MADE IN THE USA by Class A Customs using Medium Density Polyethylene (MDPE) Resin TANK NOT FOR FRESH OR DRINKING WATER USE – WASTE/GRAY WATER USE ONLY -SEAMLESS One-piece construction, no seams to burst COLOR Black OEM PART No retail box - no install instructions Have a certified technician install all parts to prevent product damage and personal injury PREPARATION Tanks are made in a warehouse clean each tank prior to use to remove any debris, scuffs or marking from the manufacturing process INSTALLED OUTLET 3” ABS Female Pipe - outlet can not be moved DO NOT over-tighten fittings damage will occur Dump valves do not hook directly to the 3" ABS fitting, from the outlet run PVC or ABS piping, dump valve is added to the piping. INLET & VENT INSTALLATION Class A Customs Black Water Tanks only come with the outlet the end user will determine where the inlet and vent will need to be placed and install, hardware NOT included. TANK MUST BE VENTED allowing air in and out when in use. *DO NOT PRESSURIZE TANK* DO NOT over-tighten fittings damage will occur. MOUNTING & BRACING be sure to secure tank to prevent movement and be sure to secure due to weight when loaded DO NOT place weight on tank.

## Features

- 40 Gallon RV Waste Water Holding Tank MADE IN THE USA by Class A Customs using Medium Density Polyethylene (MDPE) Resin TANK NOT FOR FRESH OR DRINKING WATER USE – WASTE/GRAY WATER USE ONLY – Used in RV’s Campers, Trailers, Motorhomes and Tiny Houses
- INSTALLED OUTLET 3” ABS Female Pipe - outlet can not be moved DO NOT over-tighten fittings damage will occur Dump valves do not hook directly to the 3" ABS fitting, from the outlet run PVC or ABS piping (not included), dump valve (not included) is added to the piping.
- INLET & VENT INSTALLATION Class A Customs Black Water Tanks only come with the outlet the end user will determine where the inlet and vent will need to be placed and install, hardware NOT included. TANK MUST BE VENTED allowing air in and out when in use. *DO NOT PRESSURIZE TANK* DO NOT over-tighten fittings damage will occur.
- NOT INCLUDED Inlet and Vent Fittings / Additional Fittings / Hardware / Mounting Hardware / Dump Valve / Piping NOT INCLUDED

## Technical Specifications

| Specification | Value |
|---------------|-------|
| Brand | classAcustoms |
| Color | Black |
| Material | Polyethylene (PE), Polyvinyl Chloride (PVC), Resin |
| Product Dimensions | 56.5"L x 24.5"W x 9"H |
| Capacity | 40 Gallons |
| Item Weight | 0.01 Ounces |
| Shape | Rectangular |
| Manufacturer | Class A Customs |
| Model | WT-4000 |
| Item Weight | 0.01 ounces |
| Manufacturer Part Number | WT-4000 |

## Product Details

- **Brand:** classAcustoms
- **Color:** Black
- **Material:** Polyethylene (PE), Polyvinyl Chloride (PVC), Resin
- **Product Dimensions:** 56.5"L x 24.5"W x 9"H
- **Capacity:** 40 Gallons

## Images

![Class A Customs 40 Gallon RV Waste Black Water Holding Tank WT-4000 - Image 1](https://m.media-amazon.com/images/I/71NMcwKZRaL.jpg)
![Class A Customs 40 Gallon RV Waste Black Water Holding Tank WT-4000 - Image 2](https://m.media-amazon.com/images/I/71IdWHquJIS.jpg)
![Class A Customs 40 Gallon RV Waste Black Water Holding Tank WT-4000 - Image 3](https://m.media-amazon.com/images/I/512a8EyZKnS.jpg)
![Class A Customs 40 Gallon RV Waste Black Water Holding Tank WT-4000 - Image 4](https://m.media-amazon.com/images/I/71woS1w0UYL.jpg)
![Class A Customs 40 Gallon RV Waste Black Water Holding Tank WT-4000 - Image 5](https://m.media-amazon.com/images/I/711a3fh6A9L.jpg)

## Questions & Answers

**Q: This tank showes an imput hole in the top. How big is it I couldn't find anything in the discription?**
A: The top is a mold mark in the tank. In order to fill the tank you will need to use a hole saw bit and drill a hole into the tank where needed for your unit. Then place a plastic grommet to snug the pipe in, we also sell the grommets in 3" and 1 1/2". Thank you, Class A Customs Elkhart, Indiana

**Q: What's the deal with the hose clamp on the outlet pipe**
A: The hose clamp is used for holding the outlet pipe in place in addition to adhesive.

**Q: Can this be used as an additional storing tank for waste? I still have the one on my camper but I want to add this one due to not having a septic yet.**
A: I don't see why not..? It's up to you how you use it. But I replaced my tank and works great!

**Q: what is the width of the bottom part of the tank? where can I find more details dimensions before ordering it?**
A: Please be sure to view the CAD drawing on this tank, you will need to scroll through the photos to view it.

## Frequently Bought Together

- Class A Customs 40 Gallon RV Waste Black Water Holding Tank WT-4000
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*Product available on Desertcart Singapore*
*Store origin: SG*
*Last updated: 2026-01-25*