---
product_id: 110463112
title: "Class A Customs 40 Gallon RV Waste Black Water Holding Tank WT-4000"
brand: "classacustoms"
price: "A$2000"
currency: AUD
in_stock: true
reviews_count: 8
category: "Class Acustoms"
url: https://www.desertcart.com.au/products/110463112-class-a-customs-40-gallon-rv-waste-black-water-holding
store_origin: AU
region: Australia
---

# 3” ABS Female 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:** A$2000
**Availability:** ✅ In Stock

## Summary

> ♻️ Upgrade your RV’s waste game with the tank that means business!

## 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?** A$2000 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.com.au](https://www.desertcart.com.au/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 install but engineered to withstand heavy loads
- • **Customizable Inlet & Vent:** You control placement for optimal RV plumbing integration
- • **Precision 3” ABS Outlet:** Factory-installed for secure, leak-resistant waste discharge
- • **Massive 40-Gallon Capacity:** Handles your RV’s waste needs without constant emptying
- • **Premium USA-Made MDPE Resin:** Durable, seamless one-piece construction built to last

## Overview

The Class A Customs 40 Gallon RV Waste Black Water Holding Tank WT-4000 is a rugged, seamless, one-piece tank made in the USA from medium density polyethylene resin. Designed exclusively for waste and gray water, it features a fixed 3” ABS female outlet and requires user-installed inlet and vent fittings. Ideal for RVs, campers, trailers, and tiny houses, this tank offers a large capacity and durable construction to ensure reliable, long-term performance.

## 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.

Review: Best value in a RV waste tank. - I bought this to build a shower house at our family camp site. I've done only a little rv plumbing, but I have experience with normal house plumbing. We have a septic tank and could have connected directly with a standard toilet with flush tank on the back, but I wanted to use an RV toilet to reduce the risk of the toilet freezing in winter. Anyway, the tank came very quickly and shipped free from desertcart. That alone saved a small fortune. The tank came fitted with an outlet. You'll need to buy the valve etc. I located and cut (with a hole saw) the holes for the inlet and vent. You could also use a jigsaw to cut your inlets. Make sure to order the rubber grommets for these. They only make 3" grommets so buy a bushing to step down to whatever pipe size you are using. I used 1 1/2" pvc for the vent. I also had to order a 3 7/8" hole saw as none were available locally. Once I had all the parts and tools it went together smoothly. Pro tip- Install the tank before putting your flooring down. It will be way easier. Tank has been in service for about a month now and so far so good. Great tank, free shipping, at the best price I could find locally or online.
Review: Fits just right. - It works great for our cabin.

## 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 |
|---------------|-------|
| ASIN | B07NLLQDC1 |
| Best Sellers Rank | #281,851 in Automotive ( See Top 100 in Automotive ) #25 in RV Black Water Tanks |
| Brand | classAcustoms |
| Capacity | 40 Gallons |
| Color | Black |
| Customer Reviews | 4.3 4.3 out of 5 stars (198) |
| Date First Available | February 11, 2019 |
| Item Weight | 0.01 ounces |
| Manufacturer | Class A Customs |
| Manufacturer Part Number | WT-4000 |
| Material | Polyethylene (PE), Polyvinyl Chloride (PVC), Resin |
| Model | WT-4000 |
| Product Dimensions | 56.5"L x 24.5"W x 9"H |
| Shape | Rectangular |

## Product Details

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

## Images

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

## Customer Reviews

### ⭐⭐⭐⭐⭐ Best value in a RV waste tank.
*by F***D on June 6, 2024*

I bought this to build a shower house at our family camp site. I've done only a little rv plumbing, but I have experience with normal house plumbing. We have a septic tank and could have connected directly with a standard toilet with flush tank on the back, but I wanted to use an RV toilet to reduce the risk of the toilet freezing in winter. Anyway, the tank came very quickly and shipped free from Amazon. That alone saved a small fortune. The tank came fitted with an outlet. You'll need to buy the valve etc. I located and cut (with a hole saw) the holes for the inlet and vent. You could also use a jigsaw to cut your inlets. Make sure to order the rubber grommets for these. They only make 3" grommets so buy a bushing to step down to whatever pipe size you are using. I used 1 1/2" pvc for the vent. I also had to order a 3 7/8" hole saw as none were available locally. Once I had all the parts and tools it went together smoothly. Pro tip- Install the tank before putting your flooring down. It will be way easier. Tank has been in service for about a month now and so far so good. Great tank, free shipping, at the best price I could find locally or online.

### ⭐⭐⭐⭐⭐ Fits just right.
*by T***T on December 19, 2025*

It works great for our cabin.

### ⭐⭐⭐⭐ Check the location of your existing plumbing.
*by A***R on September 15, 2020*

Tank dimensions was just what I needed, everything fit perfect, BUT, the top of the tank where the logo is was recessed right where my fitting needed to go, had to work around it,see photos, big headach, that logo needs to be moved to the bottom of the tank.

## Frequently Bought Together

- Class A Customs 40 Gallon RV Waste Black Water Holding Tank WT-4000
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- C.ROTO MOLDG Custom Roto-Molding 93 RV Tank Grommet

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---

*Product available on Desertcart Australia*
*Store origin: AU*
*Last updated: 2026-01-30*