The Three Options: Tanks, Cans, and Bladders
Every water storage system for overlanding falls into one of three categories, and each has genuine advantages that make it the right choice in specific situations. There's no universal best option — your rig layout, trip length, and budget determine what works.
Rigid Tanks: The Permanent Solution
Rigid polyethylene or rotomolded tanks are the standard for permanent water systems. They're mounted to the vehicle frame, inside the bed, under the chassis, or inside a drawer system. Sizes range from 5 gallons to 50+ gallons depending on the vehicle and mounting location.
Advantages: Durable. Low profile when mounted underneath the vehicle. Can be plumbed directly to a tap or pump. Won't shift during rough driving. Large capacity without taking up cargo space (when chassis-mounted).
Disadvantages: Permanent installation — you can't easily remove the tank when you need the space or the payload capacity. Underbody tanks are vulnerable to rock strikes. Custom tanks are expensive ($200-$800+). Cleaning the interior of an oddly shaped tank can be difficult.
Popular Rigid Tank Options
Frontrunner makes slimline tanks that fit between frame rails on most trucks and SUVs. Their 20-gallon tank is a common choice for mid-size trucks. For custom builds, companies like Aluminess and AT Overland fabricate aluminum tanks shaped to fit specific vehicles.
If you're going the DIY route, food-grade HDPE tanks from US Plastics or Tank Depot come in standard sizes that can be mounted with simple brackets. Ensure any tank you use is rated for potable water — not all plastic is food-safe.
Mounting Considerations
Underbody is the best location from a center-of-gravity standpoint — it keeps the weight low and centered. But underbody tanks need skid plate protection on rough trails. A rock that punctures your water tank at mile 50 of a desert run is a serious problem.
Bed-mounted tanks keep the water accessible and protected but eat into cargo space. If you run a truck bed with a drawer system, a tank can be integrated alongside the drawers. Measure your space carefully — a gallon of water occupies 231 cubic inches, so a 20-gallon tank needs nearly a cubic foot and a half of space before you account for the tank walls and fittings.
Jerry Cans: Simple and Flexible
Water jerry cans are the easiest entry point for overlanding water storage. No plumbing, no installation, no permanent commitment. Fill them at home, strap them to the rig, and pour when you need water.
Advantages: Cheap ($15-$40 each). No installation required. Easy to fill at any water source. Removable when not needed. Can be positioned anywhere on the vehicle. If one leaks or gets contaminated, you haven't lost your entire supply.
Disadvantages: They take up external or internal cargo space. Must be secured properly — a 7-gallon can weighs nearly 60 pounds when full, and that's a serious projectile in a rollover. Pouring from a full 7-gallon can is awkward. No tap without aftermarket spigots.
Recommended Jerry Cans
The Scepter 5-gallon military water can (BPA-free, originally designed for the US military) is the standard. It's tough, stackable, and has a wide mouth for easy filling and cleaning. The 7-gallon version exists but is heavy when full and harder to pour.
Wavian and other NATO-style metal jerry cans are designed for fuel, not water. They'll work in a pinch, but the interior coating isn't food-grade on most models. Stick with cans specifically designed for potable water.
Mounting Jerry Cans
Roof rack mounting is common but puts weight in the worst possible location — high and outside the wheelbase. Two 7-gallon cans on the roof add 116 pounds above the center of gravity. If you must mount on the roof, keep water cans centered and forward, not on the rear overhang.
Rear bumper or swing-out carrier mounting is better for weight distribution. Many aftermarket bumpers include jerry can mounts. A cargo box like the Roam Adventure Eagleview can also accommodate cans with proper securing.
Inside the vehicle is the safest location. Strap cans to the bed floor or to a fixed mounting point. Never leave a full water can unsecured in the cargo area.
Water Bladders: The Space-Efficient Option
Collapsible water bladders store flat when empty and expand to hold 2-10 gallons when full. They conform to irregular spaces and weigh almost nothing empty.
Advantages: Extremely light when empty. Conform to available space. Some include built-in taps. Cheapest option per gallon. Can be stuffed into otherwise unusable space in the vehicle.
Disadvantages: Less durable than rigid containers — punctures happen. Can develop mold if not dried properly between uses. Floppy when full, making them hard to secure. Most don't stack well. Shorter lifespan than cans or tanks.
Recommended Bladders
The MSR Dromedary bags (4, 6, and 10 liter) are the gold standard for durability. They're made from a heavy-duty laminate that resists punctures. The Sea to Summit Watercell X is a newer design with a 3D baffle structure that makes the bladder more stable when full.
For larger capacity, the Front Runner Flat Pack bladders and the Rightline Gear truck bed bladders hold 20-100 gallons and lay flat in a truck bed. These are expedition-level solutions for trips where you need massive water capacity and have the bed space.
Plumbing Basics: Building a Water System
If you install a rigid tank, plumbing it to a tap or pump system adds significant convenience. A basic water system has four components:
Tank: Your storage vessel, with threaded fittings for inlet and outlet.
Pump: A 12V diaphragm pump (Shurflo and Flojet are common brands) draws water from the tank and pressurizes the line. A 1-gallon-per-minute pump is adequate for a camp kitchen tap. Wire it to a switch on the vehicle's electrical system or to a portable power source.
Lines: Food-grade silicone or PEX tubing connects the tank to the pump and the pump to the faucet. Use quick-disconnect fittings for easy winterization and maintenance. Half-inch ID tubing is standard for most camp systems.
Tap: A simple foot-pump faucet or a hand-pump tap works without electricity. A 12V pump with a standard kitchen faucet gives you running water at the push of a switch. Mount it wherever you do dishes — tailgate, slide-out kitchen, or an exterior panel.
An inline filter between the tank and the tap improves taste and catches sediment. A basic carbon filter like the Camco TastePURE is sufficient for water that was potable when you put it in the tank.
Keeping Stored Water Fresh
Water stored in tanks and containers degrades over time. Bacteria grow. Algae form if light reaches the water. Plastic can leach chemicals, especially in heat. Keeping your water fresh requires attention to a few details:
Use food-grade containers only. Not all plastics are safe for potable water storage. Look for containers marked with recycling codes 1, 2, 4, or 5 — these are food-safe. Code 7 may contain BPA. When in doubt, buy containers specifically labeled for potable water.
Keep water out of direct sunlight. UV light promotes algae growth and accelerates chemical leaching from plastic. Opaque containers are better than translucent ones. If your tank is in the sun, consider an insulation wrap.
Sanitize regularly. At the beginning of each season, flush your tank system with a dilute bleach solution (1/4 cup of unscented household bleach per 15 gallons). Fill the tank, run the solution through all lines and taps, let it sit for several hours, then flush with clean water until you can't smell bleach. Repeat every few months during heavy use.
Don't let water stagnate. If your vehicle sits for weeks between trips, drain the water system completely. Standing water in lines and pumps is a breeding ground for bacteria and biofilm. Before your next trip, sanitize and refill.
Rotate stored water. If you keep filled jerry cans at home for emergency use, rotate the water every six months. Stored water is safe to drink for much longer than six months, but it can develop off-tastes from the container.
My Setup and Recommendation
I run a 20-gallon underbody tank plumbed to a Shurflo pump and a simple faucet at the tailgate. For longer trips, I add two Scepter 5-gallon jerry cans strapped to the bed floor. That gives me 30 gallons total — enough for two people and a dog for four to five days in the desert with modest conservation.
If you're starting out, begin with two 5-gallon jerry cans. They cost under $80 total, require zero installation, and teach you how much water you actually use per day. Once you know your consumption, you can size a permanent tank system accurately instead of guessing.
Whatever system you choose, maintain it. Sanitize before the season. Check fittings for leaks. Inspect jerry cans for cracks. And always, always carry more water than you think you need.