Best Water Supply Tank For Mobile Car Wash: 10 Options Compared

#1 · Best Overall

1. Detail King 100 Gallon Water Tank

• Capacity: 100 gallons
• Material: Polyethylene (PE)
• Weight: 50 lb

Best for: High-volume detailing routes.

Why it ranks #1: Its listing specifically targets mobile detailing, holds 100 gallons, and says it suits a pickup, van, or trailer and serves 10–15 standard-sized vehicles.

A full 100-gallon capacity is the defining advantage of this Detail King tank, which is listed as holding enough water for 10–15 standard-sized vehicles. Its UV-stabilized linear polyethylene construction also suits mobile detailing setups in a pickup truck, van, or trailer.

For an operator washing several vehicles between refills, the stated 100-gallon capacity supports a longer work sequence than a small reserve. Detail King identifies this tank for mobile detailers using pickups, vans, or trailers, tying its volume to common mobile setups. Its 38.5-by-26.5-by-25-inch dimensions give you a concrete footprint to account for when allocating vehicle space. UV stabilization supports outdoor storage, while linear polyethylene forms the tank body.

Skip it if you have limited vehicle space or need only a smaller reserve; RomoTech’s 50-gallon 82123915 has half the stated capacity.

This suits a detailer carrying water for multiple vehicles in a pickup, van, or trailer. Its 100-gallon volume is the key fit consideration, along with room for the stated tank dimensions.

Listed on Amazon as: Water Tank 100 Gallon – 38.5" x 26.5" x 25" – Mobile Detailing Work – Holds Enough Volume for 10-15 Standard Sized Vehicles

#2 · Highest Capacity Poly

2. RomoTech 50 Gallon Water Tank

• Capacity: 50 gallons
• Material: High Density Polyethylene (HDPE)

Best for: Outdoor 50-gallon reserve.

Why it ranks #2: The 50-gallon horizontal square HDPE tank offers molded level marks and a 3/4-inch NPT outlet for operators needing substantial onboard capacity.

A 50-gallon capacity gives the RomoTech 82123915 a useful middle ground for mobile washing, while molded gallon and liter marks make the stored level easy to read. Its UV-stabilized, rustproof polyethylene is specified for outdoor settings such as trailers, farms, and worksites.

The horizontal square reservoir holds 50 gallons, giving a mobile wash operator more onboard supply than a compact tank without moving to a 100-gallon format. Molded gallon and liter marks make level checks straightforward when planning the next refill. The HDPE construction is described as UV-stabilized and rustproof, supporting outdoor placement on a trailer or worksite. A 3/4-inch NPT outlet provides a defined plumbing connection, so the rest of the water-delivery setup needs to match that fitting.

Skip it if you need a full 100-gallon onboard supply for a long route; Detail King’s 100-gallon tank offers twice the stated capacity.

Choose this for a mobile washer seeking 50 gallons, readable level marks, and outdoor-ready poly storage. Check that the 3/4-inch NPT outlet works with your plumbing before planning the installation.

Listed on Amazon as: 82123915 50 Gallon Water Tank – Horizontal Square, Poly Tank for Non-Flammable Liquids, UV-Resistant Storage with Molded Gallon/Liter Marks, 3/4" NPT Outlet, Made in USA, Black

#3 · Marked Mid-Size Tank

3. RomoTech 30 Gallon Water Tank

• Capacity: 30 gallons
• Material: High Density Polyethylene (HDPE)

Best for: Marked 30-gallon outdoor tank.

Why it ranks #3: Its 30-gallon horizontal square design includes molded gallon and liter marks, making level checks easier while requiring less capacity than the 50-gallon model.

Molded gallon and liter marks make the RomoTech 82123905’s 30-gallon level easy to check during mobile wash work. Its horizontal square HDPE body is specified as UV-stabilized and rustproof, a combination intended for outdoor storage on trailers, farms, and worksites.

The 30-gallon capacity provides a middle-sized reserve for an operator who wants more than a very small onboard tank but does not need a 50- or 100-gallon format. Molded gallon and liter markings let you see the remaining level and plan replenishment. The product specifies a 3/4-inch NPT outlet, providing a defined connection point for the water system. UV-stabilized, rustproof HDPE is intended for outdoor use, making trailer or worksite placement part of its stated use case.

Skip it if you need a larger reserve for an extended route; RomoTech’s 50-gallon 82123915 provides 20 gallons more capacity.

This fits a mobile washer seeking a marked 30-gallon outdoor reservoir with a defined outlet. Its capacity and 3/4-inch NPT connection are the main boundaries to check against route length and plumbing.

Listed on Amazon as: 82123905 30 Gallon Water Tank – Horizontal Square, Poly Tank for Non-Flammable Liquids, UV-Resistant Storage with Molded Gallon/Liter Marks, 3/4" NPT Outlet, Made in USA, Black

#4 · Compact Poly Tank

4. RomoTech 26-Gallon Poly Tank

• Capacity: 26 gallons
• Material: Polyethylene (PE)
• Weight: 15.6 lb

Best for: Compact route-water storage.

Why it ranks #4: This 26-gallon polyethylene tank has a translucent body, molded graduation marks, and channels for saddle straps, useful features for a smaller vehicle setup.

Molded gallon and liter graduations make this 26-gallon RomoTech tank useful when a mobile wash operator needs to check remaining supply without guessing. Its translucent polyethylene body also lets you see the fluid level, while the domed horizontal profile provides a space-conscious shape for trailer or worksite storage.

The 26-gallon capacity suits a smaller onboard reserve or a route with planned refill access; it offers less volume than a large detailing tank. Translucent polyethylene and molded graduations support quick level checks, helping you decide when to refill before starting another vehicle. Molded-in channels give saddle straps a defined place to sit during installation. Its thick-walled construction is specified for heavy-duty use, and the included lid keeps the tank supplied as a storage vessel.

Skip it if you need a 100-gallon reserve for several vehicles; Detail King’s 100-gallon tank holds substantially more water.

This fits a mobile washer who values visible level checks and a strappable, 26-gallon reserve in a trailer or work area. Its capacity is the boundary: plan refills for longer or busier routes.

Listed on Amazon as: Poly Storage Tank – Domed, 26-Gallon Capacity, Model Number 2389

#5

5. ICON 38 Gallon Fresh Water Tank

• Weight: 23.5 lb

Best for: Shallow 38-gallon installation.

Why it ranks #5: The 38-gallon tank has three 1/2-inch FPT fittings and a 1-1/4-inch filler; its listed dimensions are 55 by 24 by 7 inches.

At a listed 55 by 24 by 7 inches, this ICON tank pairs 38 gallons of capacity with a notably shallow profile for space-constrained installations. Its product details specify impact-resistant polyethylene, three 1/2-inch FPT connections, and a 1-1/4-inch filler.

The 38-gallon capacity adds a useful reserve for mobile washing, while the stated 7-inch height can help when installation space is shallow. Three 1/2-inch FPT connections and one 1-1/4-inch filler give the plumbing layout specific connection points to account for before mounting. The polyethylene is described as impact resistant, and the tank is listed as mold- and bacteria-resistant and BPA-free. Its stated dimensions and fittings make careful space and connection planning central to the installation.

Skip it if you cannot accommodate a 55-inch tank; ICON’s 12734 is listed with a smaller 12-gallon capacity and shorter dimensions.

This suits a mobile washer with a long, shallow mounting area and a need for 38 gallons. Check the 55-inch length and specified fitting layout against your vehicle and plumbing plan.

Listed on Amazon as: ICON 14374 Fresh Water Tank, WT3594, 55x24x7, 38 Gal., w/ 1/2" Fittings

#6

6. ICON 30 Gallon Fresh Water Tank

• Capacity: 30 gallons
• Material: Plastic
• Weight: 15 lb

Best for: 30-gallon molded tank.

Why it ranks #6: This 30-gallon one-piece, roto-molded tank includes 1/2-inch fittings and measures 36 by 13 by 15 inches, offering a defined rectangular footprint.

One-piece roto-molded construction gives this ICON tank a simple 30-gallon format for a mobile wash setup that needs a defined reserve. Its listed dimensions are 36 by 13 by 15 inches, and the product information identifies it as a water tank only.

The 30-gallon capacity can serve a modest onboard supply, while the 36-by-13-by-15-inch dimensions help you plan where the tank can sit in a vehicle or trailer. One-piece roto-molded construction is specified as sturdy and durable, giving the tank a straightforward molded body rather than a multi-piece format. The listing includes 1/2-inch fittings and identifies the product as the tank only, so buyers should plan the surrounding water-delivery equipment separately.

Skip it if you need a complete pump-and-delivery setup in the same purchase; this listing identifies the item as the tank only.

This is a fit for a mobile washer needing a 30-gallon molded tank and a known footprint. Treat it as a water-storage component, not a complete wash system, and plan the remaining equipment.

Listed on Amazon as: Icon 12727 Fresh Water Tank, WT2463, 36x15x13, 30 Gal., w/ 1/2" Fittings

#7

7. ICON 26 Gallon Fresh Water Tank

• Weight: 13 lb

Best for: Compact 26-gallon tank.

Why it ranks #7: Its 26-gallon capacity and one-piece roto-molded construction may suit a smaller installation, though the listing is for a fresh-water tank rather than detailing.

The ICON 12737 lists 26 gallons of capacity in a one-piece roto-molded tank, making it a compact-volume option for a mobile wash setup. Its listed dimensions are 26 by 21 by 16 inches, while the product details identify it as a water tank only.

A 26-gallon reserve can suit a smaller mobile operation or a vehicle with limited room for water storage. The listed 26-by-21-by-16-inch dimensions give buyers a footprint to work into a trailer or vehicle layout. One-piece construction and a roto-molded design are specified for the tank body. The listing includes 1/2-inch fittings but calls the item a water tank only, so pumps, hoses, or other delivery components should be planned as part of the wider wash setup.

Skip it if you need 100 gallons for a high-volume route; Detail King’s 100-gallon tank is listed for 10–15 standard-sized vehicles.

This works for a mobile washer who wants a 26-gallon molded tank with a defined footprint. The tank-only listing means it is best for buyers already planning the rest of their water-delivery equipment.

Listed on Amazon as: ICON 12737 Fresh Water Tank, WT2473, 22x20x15, 26 Gal., w/ 1/2" Fittings

#8

8. LATHEVEE 50-Gallon Water Bladder

• Capacity: 50 gallons
• Material: Polyvinyl Chloride (PVC)

Best for: Visible-level bladder storage.

Why it ranks #8: The flexible PVC bladder holds up to 50 gallons and its transparent material shows water level, but the listing does not establish vehicle mounting or wash-system fittings.

Transparent PVC lets you observe the water level inside this LATHEVEE bladder, making it easier to judge stored supply and fill ahead of a mobile wash. The listed capacity is up to 50 gallons, and the material is described as thickened for water containment.

The transparent bladder provides a direct view of water level and stored volume, which can help an operator decide when to replenish supply before a wash shift. Its stated 50-gallon capacity offers a moderate reserve for mobile use, while the flexible bladder format differs from a rigid tank when arranging storage. The product information also says an arm can be inserted for cleaning, giving access to the interior for maintenance. PVC is the specified material; no outlet dimensions are provided.

Skip it if you need more than 50 gallons onboard; Detail King’s 100-gallon tank is listed for 10–15 standard-sized vehicles.

This suits a mobile washer who values visible water levels and interior access for cleaning in a bladder format. Its 50-gallon maximum and unspecified outlet details are important setup limits.

Listed on Amazon as: Water Storage Bladder 25/50/100Gal Water Bladder Portable Water Tank | Drought Relief,Transparent 2000D PVC Water Tank for RV, Truck Bed, Camping, Agricultural lrrigation, Firefighting

#9

9. ICON 20 Gallon Fresh Water Tank

• Weight: 0.01 oz

Best for: 20-gallon compact installation.

Why it ranks #9: This one-piece, roto-molded fresh-water tank is a compact 20-gallon option, but the supplied specifications do not state fittings or dimensions clearly.

The ICON 12736 offers a listed 20-gallon capacity in a one-piece roto-molded tank for mobile washers who need a moderate, space-conscious reserve. Its title gives 32 by 12 by 12 inches as the tank size and specifies 1/2-inch fittings.

A 20-gallon reserve sits between small auxiliary storage and a large route tank, making it relevant when a mobile setup needs some onboard water without a 100-gallon format. The listed 32-by-12-by-12-inch size helps with placement planning. One-piece construction and a roto-molded design describe the tank body, while the title’s 1/2-inch fittings give a plumbing connection detail to consider. The listing identifies it as a water tank only, not a complete wash system.

Skip it if you need water for a long, high-volume route; Detail King’s 100-gallon tank is listed for 10–15 standard-sized vehicles.

This suits a mobile washer seeking a moderate 20-gallon reserve and a compact listed footprint. Its tank-only format and capacity mean you should plan separate delivery equipment and refill intervals.

Listed on Amazon as: ICON 12736 Fresh Water Tank, WT2472, 32x12x12, 20 Gal., w/ 1/2" Fittings

#10

10. ICON 12 Gallon Fresh Water Tank

• Weight: 7 lb

Best for: Small 12-gallon reserve.

Why it ranks #10: The 12-gallon one-piece tank is the smallest listed capacity, limiting its usefulness for a mobile wash route compared with larger dedicated detailing options.

A 12-gallon capacity makes the ICON 12734 a small reserve for mobile washing when vehicle space is tight or water needs are limited. The tank is listed with one-piece construction and a roto-molded design, with 1/2-inch fittings identified in its title.

The 12-gallon capacity is suited to a limited onboard reserve rather than a long sequence of vehicle washes, so it works best when refills are accessible. One-piece construction and roto-molded design are the listed construction details for the tank. Its title identifies 1/2-inch fittings, providing a connection specification to check against the wash system. The listing calls it a water tank only, so the pump and other delivery equipment need to be handled separately.

Skip it if you need a larger onboard reserve for consecutive vehicles; ICON’s 12727 holds 30 gallons according to its supplied listing.

This is a fit for a mobile washer with limited installation space or a small water requirement and nearby refill access. Its 12-gallon capacity is the deciding boundary for route planning.

Listed on Amazon as: ICON 12734 Fresh Water Tank, WT2470, 20x12x12, 12 Gal., w/ 1/2" Fittings