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Finding a reliable 28 gallon RV holding tank that fits your rig and lasts for years is harder than it should be — until now. The Elkhart Plastics EPI 5523 / H879003 is a roto-molded, OEM-grade black or gray water holding tank engineered for the demands of full-time RV life. At 55-3/4" x 23-3/4" x 8", it's a direct-fit replacement for a wide range of Class A, Class C, and fifth-wheel applications.
Features & Specifications
- Capacity: 28 gallons — ideal mid-size holding tank for most RV configurations
- Dimensions: 55-3/4" L x 23-3/4" W x 8" H
- Wall Thickness: 0.180" black high-density polyethylene (HDPE)
- Outlet: Standard 3" outlet included; additional fittings available per quote
- Construction: Seamless roto-molded design — uniform wall thickness, no weak spots
- Material: Black polyethylene — UV-resistant, impact-resistant, odor-resistant
- Part Numbers: EPI 5523 / H879003
- Manufacturer: Elkhart Plastics / Ameri-Kart — industry-leading OEM tank supplier
Why Choose the Elkhart Plastics 28 Gallon RV Holding Tank?
Elkhart Plastics has built its reputation on one thing: tanks that don't fail. The roto-molding process used to manufacture this 28 gallon RV holding tank creates a seamless, one-piece shell with walls of equal thickness throughout. There are no seams to crack, no joints to leak, and no thin spots to worry about on rough roads.
Unlike aftermarket alternatives, this OEM-grade holding tank meets strict quality and health safety standards — the same standards used by major RV manufacturers. Whether you're replacing a failed tank or upgrading an aging system, the EPI 5523 delivers the fit, finish, and durability you need.
The standard 3" outlet is compatible with most RV waste plumbing configurations, and custom fittings can be added per quote for non-standard setups.
Compare RV Holding Tanks by Capacity
Not sure if 28 gallons is the right size for your rig? Use this comparison to find the best fit for your RV's waste system layout and travel style.
| Model / Part # | Capacity | Dimensions (L x W x H) | Brand | Best For | View Details |
|---|---|---|---|---|---|
| EPI 5523 / H879003 | 28 gal | 55-3/4" x 23-3/4" x 8" | Elkhart Plastics | Mid-size Class A/C, fifth-wheels | Current Product |
| 4283 / ERV121100 | 24 gal | 70" x 21" x 6" | Elkhart Plastics | Slim-profile, long-bay RVs | View Details |
| H1296 | 29 gal | 45" x 15-1/2" x 12-3/8" | Elkhart Plastics | Compact bays, taller clearance | View Details |
| EPI 4676 | 32 gal | 55" x 27" x 8" | Elkhart Plastics | Larger rigs, extended trips | View Details |
| VR32546HBLANK | 32 gal | 55" x 32" x 5-3/4" | Alpha | Wide, low-profile bays | View Details |
Tip: Always measure your existing tank bay (length, width, and height clearance) before ordering. A tank that's even 1" too tall or wide won't fit without modification.
Technical Specifications
- Capacity: 28 gallons
- Length: 55-3/4"
- Width: 23-3/4"
- Height: 8"
- Wall Thickness: 0.180"
- Material: Black high-density polyethylene (HDPE)
- Outlet Size: 3" standard
- Additional Fittings: Available per quote
- Manufacturing Process: Roto-molded (seamless, uniform wall thickness)
- Part Numbers: EPI 5523 / H879003
- Country of Origin: USA
- Ship Weight: ~77 lbs
What's Included
- 1x Elkhart Plastics 28 Gallon RV Holding Tank (EPI 5523 / H879003)
- Standard 3" outlet fitting
- Manufacturer quality assurance
Note: Additional fittings, mounting hardware, and hoses are not included but are available — contact us for a quote.
Compatible Models & Alternatives
This 28 gallon RV holding tank is compatible with a wide range of RV makes and models. Browse related options:
- 24 Gallon RV Holding Tank - EPI 4283 / ERV121100 — slim 70" profile
- 29 Gallon RV Holding Tank - H1296 — compact bay, taller clearance
- 32 Gallon RV Holding Tank - EPI 4676 — step up in capacity
- 32 Gallon Alpha Holding Tank - VR32546HBLANK — wide, low-profile option
Frequently Asked Questions
Is this tank compatible with my RV?
This tank measures 55-3/4" x 23-3/4" x 8" and is designed as a direct-fit OEM replacement for many Class A, Class C, and fifth-wheel RVs. Always verify your bay dimensions before ordering.
Can I use this as a black water or gray water tank?
Yes. The EPI 5523 / H879003 is suitable for both black water (toilet waste) and gray water (sink/shower drain) applications.
How do I install a replacement RV holding tank?
Installation typically involves draining and removing the old tank, disconnecting fittings, and securing the new tank in the bay. We recommend consulting your RV's service manual or a certified RV technician for installation.
What fittings does this tank come with?
The tank includes a standard 3" outlet. Additional fittings (inlet, vent, sensor ports) can be added per quote — contact us via AI Live Chat for a custom fitting quote.
Where can I buy an authentic Elkhart Plastics RV holding tank?
ElkhartRVParts.com is the only authorized online source for genuine Elkhart Plastics / Ameri-Kart tanks. Beware of unauthorized resellers offering counterfeit or substandard alternatives.
What's the weight capacity or pressure rating of this tank?
This tank is manufactured to OEM quality standards with 0.180" HDPE walls. It is designed for standard RV waste system pressures. Contact us for specific load or pressure specifications.
Why Buy from Elkhart RV Parts?
- Authorized dealer for Elkhart Plastics / Ameri-Kart — guaranteed authentic OEM parts
- Ships direct from our warehouse — fast, reliable freight delivery
- Expert support via AI Live Chat — get fitment help before you buy
- Hassle-free returns on uninstalled, undamaged items
- Trusted by RV owners, dealers, and service centers nationwide
Use our AI Live Chat to confirm fitment for your specific RV make, model, and year — and get a quote for any additional fittings or accessories you need.
| QAI Certification | REC 559-1 |
|---|---|
| Part number | H879003/5523 |
| Capacity (gallons) | 28 |
| Dimensions (inches) | 55-3/4 x 23-3/4 x 8 |
| Lead time | |
| Best for | RV fresh water storage tank |
- What are the dimensions of the 28 gallon rv holding tank? The tank measures 55-3/4 inches in length, 23-3/4 inches in width, and 8 inches in height.
- What material is the 28 gallon rv holding tank made of? It is made of black polyethylene with a wall thickness of 0.180 inches.
- Does the tank come with an outlet? Yes, all tanks come standard with a 3-inch outlet. Additional fittings can be added per quote.
- Is the tank seamless and durable? Yes, the tank is made using a roto-molding process which creates a seamless tank with uniform wall thickness, making it strong and durable.
- What is the purpose of the sealed hole on top of the tank? The sealed hole on top is a venting hole used during the manufacturing process and has no functional use for the end-user.
Factory-Fresh OEM Parts — the same brands installed in new RVs straight from Elkhart. Genuine, name-brand components made to order — never generic, never outdated. Sourced directly from the original RV manufacturers for perfect fit and factory-level quality.