Living the van life means every gallon counts, especially when it comes to managing your grey water. A reliable tank keeps your space clean, odor-free, and ready for the next adventure. But with so many shapes, sizes, and port configurations on the market, choosing the right one can feel overwhelming.
This guide breaks down the top 10 van grey water tanks, focusing on fit, capacity, and ease of installation. Whether you are converting a Sprinter or upgrading a camper, you will find clear, practical details to help you make a confident choice.
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Fresh and Gray Water Holding Tank | Combo Pack | RV Water Holding Tanks | C…
Best forCompact van dual-tank setups
- Seamless one-piece construction
- Two sizes for flexibility
ConsiderRequires venting setup
classAcustoms | T-4000 | One (1) RV Fresh Water 40 Gallon Tank, Grey Water
Best forLarge capacity grey water storage
- NSF-approved safe materials
- Rotatable design for fitting
ConsiderLarge footprint needs space
RecPro 40 Gallon RV Water Tank 57" x 29 3/4" x 5 3/4" | Includes Universal …
Best forLow-profile underfloor installations
- Ultra-slim 5.75-inch depth
- Made in America
ConsiderWide footprint may not fit all
TORVA 33-Gallon Non-Standard RV Wheel Well Fresh Water Storage Tank for Dri…
Best forSprinter and Transit wheel wells
- Custom wheel well fit
- Four pre-drilled ports
ConsiderRequires lift for ProMaster
Class A Customs | T-4600 | One (1) RV Fresh Water 46 Gallon Tank, Grey Water
Best forExtended off-grid grey water needs
- High 46-gallon capacity
- Rotatable for flexible fit
ConsiderLarge size may be heavy
Fresh and Gray Water Holding Tank | Combo Pack | RV Water Holding Tanks | C…
Best forLarge van builds with dual tanks
- Two large tanks included
- Seamless construction
ConsiderRequires significant space
Fresh Gray Water Holding Tank Combo – RV & Camper – BPA Free (16 & 21 Gallon)
Best forMid-size vans with dual needs
- Two tank sizes included
- Seamless one-piece build
ConsiderNo discharge hub included
RV Fresh Water Tank, Sptinter 2500 & Transit 33-Gallon Non-Standard RV Whee…
Best forDriver side wheel well storage
- Custom driver side fit
- 33-gallon capacity
ConsiderDriver side only
Fresh and Gray Water Holding Tank | Combo Pack | RV Water Holding Tanks | C…
Best forStandard van fresh and grey split
- Two tank sizes included
- Seamless construction
ConsiderVenting required
classAcustoms 24394 RV Grey Water Tank 24" x 39" x 4 | RV Waste Water Tank …
Best forTight spaces needing slim tank
- Ultra-slim 4-inch depth
- Pre-installed discharge hub
ConsiderSmall 13-gallon capacity
A.A Fresh and Gray Combo Pack – Dual Tank Versatility
Brand: A.A
A practical dual-tank solution for small van builds needing separate fresh and grey storage.
This combo pack gives you a 10-gallon and a 16-gallon tank, perfect for separating fresh and grey water in a compact van. The 10-gallon unit measures 17 by 14 by 10 inches, while the 16-gallon tank is 24 by 15 by 10 inches, so you can tuck them under a bed or bench with ease. Both are rotationally molded from durable polyethylene, ensuring they handle the bumps of the road.
Each tank includes one 1.25-inch fill inlet and three 3/8-inch NPT connections, giving you flexibility for your plumbing setup. The one-piece seamless construction means no weak seams to burst, a critical feature for long-term reliability. Just remember these are non-pressurized, so you must vent them properly during use.
- Seamless one-piece construction
- Two sizes for flexibility
- BPA-free polyethylene material
- Requires venting setup
- No pre-installed discharge hub
classAcustoms T-4000 – 40 Gallon Grey Water Workhorse
Brand: classAcustoms
A robust 40-gallon tank that adapts to your van's layout with its rotatable design.
If you need serious capacity, the classAcustoms T-4000 offers 40 gallons of storage in a tank that measures 39.5 inches long, 13 inches high, and 18 inches wide. You can rotate it to sit on any side, letting you adjust the height or width to fit your van’s undercarriage. Made from NSF-approved materials, it is safe for both fresh and grey water, giving you flexibility in how you use it.
The tank comes with two 1.5-inch female NPT fittings that are sealed watertight—just remove the membrane with a razor knife to use them. It also has two 0.5-inch open female NPT fittings for smaller connections. Since it is non-pressurized, you must vent it to allow air in and out, but the built-in fittings make installation straightforward.
- NSF-approved safe materials
- Rotatable design for fitting
- Multiple built-in fittings
- Large footprint needs space
- Fittings require manual prep
RecPro 40 Gallon Tank – Slim Profile for Tight Spaces
Brand: RecPro
A space-saving 40-gallon tank that fits tight vertical gaps with ease.
The RecPro 40-gallon tank is a slim option at just 5.75 inches deep, making it ideal for sliding under a van’s floor or between frame rails. Its dimensions of 57 inches long and 29.75 inches wide give you a large footprint, but the low profile maximizes vertical clearance. Made in America from high-density plastic, it is built to withstand the rigors of off-grid travel.
The rotationally molded body ensures uniform thickness and strength, reducing the risk of stress cracks. It includes a universal fittings kit, so you have what you need to connect your plumbing right out of the box. This tank is a smart choice if you have a wide, flat space but limited height under your van.
- Ultra-slim 5.75-inch depth
- Made in America
- Includes universal fittings kit
- Wide footprint may not fit all
- No pre-drilled ports
TORVA 33-Gallon Wheel Well Tank – Maximize Unused Space
Brand: TORVA
An innovative tank that turns dead space into 33 gallons of reliable storage.
The TORVA tank is engineered to fit perfectly over your van’s wheel arch, transforming that awkward space into 33 gallons of usable water storage. It is custom-fit for Sprinter 2500, Ford Transit, and Dodge ProMaster vans (with a 3.5-inch lift required for ProMaster). This design lets you reclaim space that would otherwise go to waste, a huge win for compact van builds.
Constructed from high-quality LLDPE with a matte finish, it offers enhanced wear resistance and impact durability. The tank features four 1.5-inch NPT pre-drilled ports, giving you flexible options for inlet, outlet, and vent connections. This makes installation easier and more adaptable to your specific plumbing layout.
- Custom wheel well fit
- Four pre-drilled ports
- Durable matte LLDPE
- Requires lift for ProMaster
- Specific van compatibility
classAcustoms T-4600 – 46 Gallon High-Capacity Option
Brand: classAcustoms
A generous 46-gallon tank that offers flexibility and safety for serious van lifers.
For those who want maximum grey water capacity, the classAcustoms T-4600 delivers 46 gallons in a tank measuring 42 inches long, 14 inches high, and 18 inches wide. Like its smaller sibling, it can sit on any side, letting you adjust the dimensions to fit your van’s undercarriage. Made from NSF-approved materials, it is safe for both fresh and grey water, offering versatility.
The tank includes two 1.5-inch female NPT fittings that are sealed watertight—simply remove the membrane with a razor knife to open them. It also has two 0.5-inch open female NPT fittings for additional connections. Remember, this is a non-pressurized tank, so proper venting is essential for smooth water flow.
- High 46-gallon capacity
- Rotatable for flexible fit
- NSF-approved materials
- Large size may be heavy
- Fittings need manual prep
A.A Combo Pack 30 & 42 Gallon – Bulk Storage Solution
Brand: A.A
A comprehensive dual-tank package for vans needing substantial water storage.
This combo pack from A.A provides a 30-gallon and a 42-gallon tank, giving you ample storage for both fresh and grey water. The 30-gallon tank measures 34 by 18 by 12 inches, while the 42-gallon tank is 39 by 18 by 14 inches, so you can place them in different areas of your van. Both are rotationally molded from durable polyethylene, ensuring long-lasting performance.
Each tank comes with one 1.25-inch fill inlet and three 3/8-inch NPT connections, offering flexibility for your plumbing. The one-piece seamless construction eliminates the risk of seam bursts, a key reliability factor. As with all non-pressurized tanks, you must vent them properly to allow air circulation.
- Two large tanks included
- Seamless construction
- BPA-free material
- Requires significant space
- Venting is mandatory
A.A Combo 16 & 21 Gallon – Mid-Size Flexibility
Brand: A.A
A versatile combo that fits mid-size vans needing both fresh and grey water storage.
The A.A combo pack with 16 and 21-gallon tanks strikes a balance between capacity and space efficiency. The 16-gallon tank measures 24 by 15 by 10 inches, while the 21-gallon tank is 39 by 16 by 8 inches, making them suitable for various van layouts. Both are made from durable polyethylene with a one-piece seamless design, so you can trust their strength.
Each tank includes one 1.25-inch fill inlet and three 3/8-inch NPT connections, giving you multiple options for hoses and fittings. The rotational molding ensures uniform thickness, reducing weak points. Just remember to vent these non-pressurized tanks to prevent pressure buildup.
- Two tank sizes included
- Seamless one-piece build
- Flexible NPT connections
- No discharge hub included
- Venting required
KORVOS 33-Gallon Wheel Well Tank – Driver Side Fit
Brand: KORVOS
A tailored wheel well tank that adds 33 gallons without sacrificing living space.
The KORVOS tank is specifically designed for the driver’s side of Sprinter 2500 and Transit vans, offering a custom fit that maximizes space. It is engineered to sit over the wheel well, turning that unused area into 33 gallons of water storage. This is a smart solution for van builders who want to keep their floor space clear.
Made from high-quality materials, this tank is built to withstand the demands of travel. Its design ensures a seamless fit, and the included ports allow for flexible plumbing connections. If you have a lifted ProMaster, it is also compatible, making it a versatile choice for popular van models.
- Custom driver side fit
- 33-gallon capacity
- Compatible with lifted ProMaster
- Driver side only
- Requires specific van model
A.A Combo 21 & 30 Gallon – Balanced Capacity Combo
Brand: A.A
A dependable combo for vans that need separate fresh and grey water tanks.
This A.A combo pack offers a 21-gallon and a 30-gallon tank, providing a solid balance for van life. The 21-gallon tank measures 39 by 16 by 8 inches, while the 30-gallon tank is 34 by 18 by 12 inches, so you can position them to fit your layout. Both are rotationally molded from durable polyethylene, ensuring they hold up over time.
Each tank includes one 1.25-inch fill inlet and three 3/8-inch NPT connections, giving you flexibility for your plumbing setup. The one-piece seamless construction means no seams to worry about, adding to their reliability. As with all non-pressurized tanks, proper venting is essential for smooth operation.
- Two tank sizes included
- Seamless construction
- BPA-free polyethylene
- Venting required
- No pre-installed hubs
classAcustoms 13 Gallon Slim Tank – Compact Grey Water Option
Brand: classAcustoms
A compact, ready-to-install grey water tank for vans with minimal clearance.
If space is at a premium, the classAcustoms 13-gallon tank is a slim solution at just 4 inches deep, measuring 24 by 39 inches. This low profile makes it easy to slide under a van’s chassis or into a tight cavity. It is specifically designed for grey water use, so you can dedicate it solely to that purpose.
Made in the USA from one-piece polyethylene construction, this tank is built to last. It comes with a 1.5-inch ABS discharge hub already installed, saving you time on installation. This is a great choice for van builders who need a compact, reliable grey water tank without extra bulk.
- Ultra-slim 4-inch depth
- Pre-installed discharge hub
- Made in USA
- Small 13-gallon capacity
- Grey water only
Buyer’s Guide: What to Consider
Choosing the right grey water tank for your van involves balancing capacity, space, and installation ease. This guide covers key factors like size, material, and fittings to help you make an informed decision for your build.
- Capacity: Consider how much grey water you generate daily. A larger tank means fewer dumps, but it takes up more space and adds weight. For a van, 10-20 gallons is typical for weekend trips, while 30-46 gallons suits full-time living.
- Dimensions and Fit: Measure your available space carefully. Tanks come in various shapes, including slim profiles for underfloor mounting and wheel well designs. Always check the tank's length, width, and height, and consider if it can be rotated to fit your specific layout.
- Material and Construction: Look for rotationally molded polyethylene, which offers seamless, durable construction. This reduces the risk of leaks and cracks. NSF-approved materials are a plus if you plan to use the tank for fresh water, ensuring safety for drinking water.
- Fittings and Ports: Check the number and size of pre-drilled ports. Standard 1.5-inch NPT fittings are common for inlets and outlets, while smaller 0.5-inch ports are useful for sensors or vents. Some tanks come with sealed fittings that you open with a knife, so plan your installation.
- Venting Requirements: All non-pressurized tanks must be vented to allow air in and out during filling and draining. Without proper venting, you risk vacuum locks or pressure buildup. Ensure your installation includes a vent line to a safe location, typically routed to the exterior.
Conclusion
Selecting the best van grey water tank comes down to your specific space and usage needs. For compact builds, the A.A combo packs offer versatile dual-tank options, while the TORVA and KORVOS wheel well tanks maximize unused space. If you need high capacity, the classAcustoms T-4000 and T-4600 deliver with rotatable designs.
Always prioritize proper venting and secure mounting to ensure reliable performance. Whether you are a weekend warrior or a full-time van dweller, the right tank will keep your adventures clean and comfortable.
Erica Steven is the founder and lead writer of WorstBrands, a site dedicated to providing honest and trustworthy reviews about outdoor gear and fashion products.
With a passion for exploring the great outdoors and staying up to date on the latest fashion trends, Erica uses her expertise to provide valuable insights into the products that matter most to her readers.
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