ICON - 12 Gallon RV Holding Tank - 38.75" x 24" x 4.25" - H3857 - Ultra Low Profile Black/Gray Water

The ICON 12-gallon holding tank is built with extra-thick, durable material to handle black, gray, or combination waste. Measuring 38.75" x 24" x 4.25", it features preinstalled drain and level sensors on most tanks for easy monitoring. Certified to IAPMO and CSA standards, this tank is a reliable replacement for model H1104 and is crafted by trusted ICON Technologies.
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The ICON H3857 12 Gallon RV Holding Tank delivers compact waste management in an ultra low-profile 38.75" x 24" x 4.25" design perfect for RVs with extremely limited vertical clearance. Engineered with extra-thick polyethylene construction and preinstalled drain and level sensors, this IAPMO-certified tank provides durable black water or gray water storage for compact travel trailers, pop-up campers, and small motorhomes. Whether you're replacing a damaged H1104 tank or upgrading your RV's waste capacity, the H3857 offers professional-grade quality in the shallowest profile available.

Features & Specifications

• 12 Gallon Capacity: Compact waste storage ideal for weekend trips and short camping excursions
• Ultra Low-Profile Design: Exceptionally slim 4.25" height fits the shallowest underbelly compartments with 38.75" x 24" footprint
• Extra-Thick Material: Heavy-duty polyethylene construction resists cracking, warping, and chemical damage
• Preinstalled Sensors: Factory-installed drain and level sensors eliminate custom drilling and installation time
• Dual-Purpose Application: Suitable for black water or gray water storage depending on your RV configuration
• IAPMO & CSA Certified: Meets rigorous North American safety and quality standards for RV holding tanks
• Direct Replacement: Replaces H1104 for exact-fit installation in compatible RV models

Why Choose the ICON H3857 Holding Tank?

When you need a reliable 12-gallon holding tank with an ultra low-profile design, the ICON H3857 delivers professional-grade quality for the most space-constrained RV applications. The extra-thick polyethylene construction provides superior durability compared to standard tanks, while the preinstalled sensors save you hours of installation time. At just 4.25" tall, this is one of the shallowest holding tanks available, making it perfect for pop-up campers, compact travel trailers, and RVs with minimal underbelly clearance.

ICON Technologies has built a reputation for engineering holding tanks that outlast OEM replacements. The H3857's IAPMO and CSA certifications ensure you're getting a tank that meets strict safety standards for waste containment. Whether you're a DIY RV owner tackling a tank replacement or a mobile technician servicing compact rigs, the H3857 offers the perfect balance of capacity, quality, and ultra-compact dimensions.

Compare ICON Holding Tanks

Not sure if the 12-gallon H3857 is the right size for your RV? Compare it against other ICON holding tanks with compact capacities to find the perfect fit for your underbelly space and waste capacity needs.

💡 Pro Tip: Measure your RV's underbelly compartment carefully before ordering. The H3857's ultra-slim 4.25" height makes it ideal for the shallowest spaces, but verify you have at least 38.75" length and 24" width clearance.

Technical Specifications

• Part Number: H3857
• Manufacturer: ICON Technologies (Icon Direct)
• Capacity: 12 Gallons (45.4 Liters)
• Length: 38.75 inches
• Width: 24 inches
• Height: 4.25 inches (ultra low-profile design)
• Material: Extra-thick polyethylene (UV and chemical resistant)
• Construction: Seamless one-piece rotational molding
• Sensors: Preinstalled drain and level sensors
• Application: Black water or gray water holding tank
• Certifications: IAPMO and CSA certified
• Replaces: H1104
• Weight: Approximately 15-20 lbs (empty)
• Ideal For: Pop-up campers, compact travel trailers, small motorhomes with minimal underbelly clearance

What's Included

• ICON H3857 12-gallon holding tank with preinstalled sensors
• Factory-installed drain fitting
• Factory-installed level sensor probes
• IAPMO/CSA certification documentation
• Installation requires separate mounting hardware and plumbing connections (not included)

Note: This is a blank tank with preinstalled sensors. Additional fittings, valves, and mounting straps are sold separately. Browse our tank fittings collection for compatible accessories.

Compatible Models & Alternatives

The ICON H3857 is a direct replacement for H1104 and fits many compact RV models with similar underbelly dimensions. If you're looking for related products or alternative tank sizes, explore these options:

• Browse all RV holding tanks - Complete selection of black water and gray water tanks
• Tank fittings and accessories - Valves, sensors, drain fittings, and mounting hardware
• All ICON Technologies products - Complete ICON catalog including fresh water tanks

Frequently Asked Questions

How do I know if the H3857 will fit my RV?

Measure your existing tank or underbelly compartment carefully. The H3857 requires a minimum space of 38.75" length x 24" width x 4.25" height. Check clearances around plumbing connections and mounting points. If you're replacing an H1104 tank, the H3857 is a direct fit replacement.

Can I use this tank for both black water and gray water?

Yes, ICON holding tanks are designed for dual-purpose use. You can use the H3857 for black water (toilet waste), gray water (sink/shower drainage), or a combination system depending on your RV's plumbing configuration. The extra-thick polyethylene construction handles both applications.

Is 12 gallons enough capacity for my RV?

A 12-gallon holding tank is ideal for compact RVs, pop-up campers, and weekend camping trips. For reference, a typical RV toilet flush uses about 0.5 gallons, so you'd get approximately 24 flushes before needing to dump. If you camp for extended periods or have a larger family, consider upgrading to the 18-gallon HT600A-SD for 50% more capacity.

Does this tank come with fittings and valves installed?

The H3857 comes with preinstalled drain and level sensors, but it does not include gate valves, vent fittings, or inlet connections. This allows you to customize the tank with fittings that match your specific RV plumbing setup. Shop our tank fittings collection for compatible accessories.

How do I install the H3857 holding tank?

Installation requires removing your old tank, positioning the H3857 in the underbelly compartment, securing it with mounting straps or brackets, and connecting the drain valve, vent line, and inlet plumbing. If you're replacing an H1104, the sensor connections should match your existing wiring. Professional installation is recommended if you're not experienced with RV plumbing systems.

What makes this tank "ultra low-profile"?

At just 4.25" tall, the H3857 is one of the shallowest holding tanks available. This ultra low-profile design allows it to fit in underbelly spaces where standard tanks (typically 6-9" tall) won't fit. It's specifically engineered for pop-up campers and compact RVs with minimal vertical clearance.

Why Buy from Elkhart RV Parts?

As an authorized ICON Technologies dealer, Elkhart RV Parts guarantees 100% authentic OEM-grade holding tanks backed by manufacturer warranties. Our team specializes in RV plumbing components and can help you select the right tank size and configuration for your specific RV model. Every ICON tank we sell is built to rigorous IAPMO and CSA standards, ensuring safe and reliable waste management for years of RV adventures.