{"id":284,"date":"2026-06-07T01:00:00","date_gmt":"2026-06-07T05:00:00","guid":{"rendered":"https:\/\/www.buslife.site\/garage\/?p=284"},"modified":"2026-03-14T18:25:23","modified_gmt":"2026-03-14T22:25:23","slug":"what-size-water-tank-do-you-need-for-a-skoolie","status":"publish","type":"post","link":"https:\/\/www.buslife.site\/garage\/what-size-water-tank-do-you-need-for-a-skoolie\/","title":{"rendered":"What Size Water Tank Do You Need for a Skoolie?"},"content":{"rendered":"\n

You’re deep into planning your bus build and the water tank question is sitting there staring at you. Too small and you’re filling up every other day. Too big and you just ate half your storage space and added 600 pounds to your bus. (See our guide on How Do You Get Water in a Converted Bus?<\/a> for more on this.)<\/p>\n\n\n\n

For most full-size skoolie conversions, a 40 to 80 gallon freshwater tank hits the sweet spot. A couple living in a bus and taking short showers, cooking, and washing dishes can stretch 50 gallons to about five to seven days without much effort. Solo travelers can get away with 30 to 40 gallons. Families should look at 60 to 100 gallons. The “right” size comes down to how many people are using it, how often you want to fill up, and whether you’re running a shower, a washer, or both.<\/strong><\/p>\n\n\n\n

“Love the floor plan but with showers and washer etc. what size tank do you have and how’s water pressure?”<\/h2>\n\n\n\n

This question comes up constantly, and I get it. You see a gorgeous build with a full shower, a kitchen sink, maybe even a compact washer, and you’re thinking “there’s no way that runs off one tank.” But it does. Most of the time. (See our guide on Can You Put a Washer and Dryer in a School Bus?<\/a> for more on this.)<\/p>\n\n\n\n

\"Love<\/figure>\n\n\n\n\n

When I was researching this, I kept finding that the majority of builds with both a shower and a washer are running somewhere between 60 and 100 gallons of fresh water. The shower is the big draw. A short navy shower — get wet, turn it off, soap up, rinse — uses about 2 to 3 gallons. A normal shower where you just let it run, more like 5 to 8 gallons. If you’ve got two people showering every day the normal way, that’s 10 to 16 gallons just on showers. Add cooking, dishes, drinking water, hand washing, and you’re looking at another 5 to 8 gallons a day for a couple.<\/p>\n\n\n\n

So where does the washer fit in? Well, those compact portable washers people use in skoolies typically pull about 10 to 15 gallons per load. That’s a significant hit to your tank. I talked to a guy who had a small washer in his full-size build and he said laundry day basically meant he had to plan a fill-up within the next day or two. He was running an 80 gallon tank and doing laundry once a week, and between showers and the washer, he was burning through water fast. His solution was pretty simple — he just made sure laundry day lined up with being somewhere he could refill. (See our guide on How Do You Do Laundry Living in a Bus?<\/a> for more on this.)<\/p>\n\n\n\n

Now, water pressure. This one is easier than people think. A standard 12V RV water pump — Shurflo and Flojet are the two brands you see everywhere — puts out 40 to 60 PSI. That’s roughly what you’d get from a house faucet. The pump is demand-activated, so when you open a tap it kicks on automatically, and when you close it the pump shuts off. Costs about $50 to $100 for a good one, and honestly it just works. I haven’t heard many people complain about pressure unless their pump is undersized or dying.<\/p>\n\n\n\n

“How big are your water tanks?”<\/h2>\n\n\n\n

I spent a lot of time looking at different builds to see what people were actually installing, not just what forums recommended. And the range is wider than I expected.<\/p>\n\n\n\n

\"How<\/figure>\n\n\n\n\n

Short buses — the ones under 25 feet — tend to have 20 to 40 gallon tanks because that’s just what fits. There’s less space under the bus, less space inside, and fewer people living in them. For weekend warriors or solo travelers, 20 to 30 gallons is honestly fine. You’re not running a resort, you’re living simply.<\/p>\n\n\n\n

Full-size buses in the 35 to 40 foot range, that’s where things open up. Most of the builds I looked at fell somewhere in the 50 to 80 gallon range for freshwater. A few of the bigger builds, especially families, had 100 gallon tanks or even dual-tank setups where they split the fresh water into two separate tanks for weight distribution.<\/p>\n\n\n\n

Here’s the math that changed how I thought about this. Water weighs 8.3 pounds per gallon. So an 80 gallon tank when it’s full adds 664 pounds to your bus. A 100 gallon tank? 830 pounds. That’s almost half a ton of water sloshing around. And that matters because every bus has a GVWR — gross vehicle weight rating — that you can’t exceed without blowing past what the brakes and tires and suspension were designed to handle. I wrote about this more in the cost breakdown article, but basically, bigger isn’t always better when it comes to tanks.<\/p>\n\n\n\n

One thing I noticed is that a lot of experienced builders run their tank at half-full most of the time and only top off completely when they know they’re going somewhere without hookups for a while. Less weight on the road, less fuel burned, and you still have plenty of water for a few days.<\/p>\n\n\n\n

“Why isn’t that water tank outside underneath the bus? There’s so much storage. Of course, you want to insulate it, but the water tank should be outside the bus”<\/h2>\n\n\n\n

So this is one of those comments I see where the person asking has a really good point on paper, and honestly I thought the same thing at first. There’s all this space under the bus, bolted to the frame rails, out of sight, out of mind. Why would you ever waste precious interior square footage on a water tank?<\/p>\n\n\n\n

\"Why<\/figure>\n\n\n\n\n

Well, I’ll tell you the reason most builders don’t just automatically go under-bus, and it’s one word. Freezing.<\/p>\n\n\n\n

If you ever plan to be anywhere below 32 degrees Fahrenheit — and most full-timers will be at some point, even if they’re chasing warm weather — an exposed tank under the bus is a ticking time bomb. Water expands when it freezes. Pipes crack. Fittings burst. And you wake up one morning in Arizona after an unexpected cold snap and you’ve got no water and a busted system. I read a story about a couple parked in New Mexico in December who thought it wouldn’t get that cold. They had an under-bus tank with no insulation or heat tape. One night it dropped to 28 and their tank didn’t completely freeze, but a fitting on the output line cracked and they lost about 30 gallons before they realized what happened.<\/p>\n\n\n\n

Now, if you’re building a warm-weather-only bus and you’re committed to staying south of the freeze line year-round, under-bus works great. You bolt the tank to the frame rails, free up all that interior space, and call it a day. Lots of builders in Florida, Texas, and the Southwest do exactly this.<\/p>\n\n\n\n

But for everyone else, the interior tank is the safer play. Your bus’s insulation and heating system keep the water above freezing without any extra effort. The tradeoff is you lose some interior space, usually under a bench seat, inside a cabinet, or tucked into a corner somewhere. I’ve seen some really clever mounting solutions where people build the tank into a step-up platform for the bedroom or hide it under the couch.<\/p>\n\n\n\n

The compromise that I see a lot of smart builders make is freshwater tank inside, gray water tank underneath. Your gray tank can freeze and it’s not a crisis. You’re not drinking from it, and even if it freezes solid, worst case you just can’t dump until it thaws. Some people add heat tape to the gray tank drain valve just so they can still dump in cold weather, but the tank itself freezing isn’t going to ruin your day the way a freshwater freeze will.<\/p>\n\n\n\n

And about the insulation argument in the original question — yeah, you can insulate an under-bus tank. You can wrap it in foam board or spray foam and add heat tape to the pipes. Some people even install heated tank pads that run off 12V. But now you’re adding complexity, electrical draw, and another thing that can fail. When I weighed all of that against just putting the tank inside, putting it inside seemed like the simpler call for anyone who doesn’t want to be limited to warm climates only.<\/p>\n\n\n\n\n\n

Related:<\/strong> What Kind of Toilet Should You Use in a Skoolie?<\/a><\/p>\n\n\n

“Amazing conversion but some queries. How big was your water tank?”<\/h2>\n\n\n\n

This question gets asked on basically every single build tour video I’ve watched. People see a finished build and they immediately want to know the tank size because it tells you a lot about how practical the bus actually is for full-time living versus just looking good on camera.<\/p>\n\n\n\n

\"Amazing<\/figure>\n\n\n\n\n

What I found after going through dozens of builds is that the most common setup for a full-time couple is a 50 to 65 gallon freshwater tank and a 30 to 40 gallon gray water tank. That combination gives you about five to seven days of water between fill-ups if you’re being reasonably careful. Not obsessively conserving, just not wasteful.<\/p>\n\n\n\n

The builds that went bigger, like 80 to 100 gallons, were almost always families or people who planned to boondock for extended periods on BLM land or national forest dispersed camping spots. When you’re 20 miles from the nearest water source and you want to stay parked for two weeks, having a bigger tank isn’t a luxury, it’s a necessity.<\/p>\n\n\n\n

But here’s the thing I want to be honest about. Tank size is only half the equation. How you USE water matters just as much. I found people with 40 gallon tanks lasting longer than people with 80 gallon tanks because their habits were dialed in. Navy showers instead of long ones. Washing dishes in a small basin instead of running the faucet. Catching rinse water in a bucket for other uses. One woman told me she got her water usage down to about 4 gallons a day living solo, which means her 40 gallon tank lasted nearly 10 days.<\/p>\n\n\n\n

The other factor is where you’re traveling. If you’re doing the RV park circuit and you’ve got hookups at every stop, tank size barely matters because you’re plugged into unlimited water most of the time. Your tank is really just for the drives between parks. But if you’re doing a lot of free camping, public lands, or staying at friends’ properties with no hookups, a bigger tank gives you more freedom between fill-ups and that’s worth the extra weight and space.<\/p>\n\n\n\n

When I was trying to figure all this out for myself, I kept coming back to the same thing. Start with how many people, figure out your daily usage, and decide how many days you want between fills. For us, something in the 55 to 65 gallon range made the most sense. Not so big that we’re hauling around unnecessary weight, not so small that we’re constantly thinking about water. If you want the full picture on how your water system connects to everything else in your build — pumps, PEX lines, hot water heaters, gray water — we put together a complete guide to skoolie plumbing and water systems that walks through all of it. And if you’re wondering where you actually fill the tank, we covered that too in how to get water in a converted bus. (See our guide on Skoolie Plumbing and Water Systems: The Complete Guide<\/a> for more on this.)<\/p>\n\n\n\n

After all the research, here’s what it comes down to. Don’t overthink the tank size. Figure out your daily usage, pick a tank that gives you five to seven days of buffer, and make sure your bus can handle the weight. That’s really it. The water system is one of the more straightforward parts of a build once you stop agonizing over the numbers and just pick something reasonable.<\/p>\n","protected":false},"excerpt":{"rendered":"

You’re deep into planning your bus build and the water tank question is sitting there staring at you. Too small and you’re filling up every other day. Too big and you just ate half your storage space and added 600 pounds to your bus. (See our guide on How Do You Get Water in a … Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":550,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6,16],"tags":[],"class_list":["post-284","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-builds","category-water"],"_links":{"self":[{"href":"https:\/\/www.buslife.site\/garage\/wp-json\/wp\/v2\/posts\/284","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.buslife.site\/garage\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.buslife.site\/garage\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.buslife.site\/garage\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.buslife.site\/garage\/wp-json\/wp\/v2\/comments?post=284"}],"version-history":[{"count":3,"href":"https:\/\/www.buslife.site\/garage\/wp-json\/wp\/v2\/posts\/284\/revisions"}],"predecessor-version":[{"id":2128,"href":"https:\/\/www.buslife.site\/garage\/wp-json\/wp\/v2\/posts\/284\/revisions\/2128"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.buslife.site\/garage\/wp-json\/wp\/v2\/media\/550"}],"wp:attachment":[{"href":"https:\/\/www.buslife.site\/garage\/wp-json\/wp\/v2\/media?parent=284"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.buslife.site\/garage\/wp-json\/wp\/v2\/categories?post=284"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.buslife.site\/garage\/wp-json\/wp\/v2\/tags?post=284"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}