Ever dreamed of pulling into a remote campsite and having the freedom to stay for a whole week, not just a quick weekend? That's the kind of freedom a 100-gallon water tank brings to the table. For RVers who are serious about getting off-grid, this single upgrade is a complete game-changer, transforming your adventures by giving you longer stays and way less anxiety about where your next fill-up is coming from.
Your Guide to Off-Grid Freedom
A 100-gallon tank is so much more than a plastic container; it's your ticket to extended boondocking trips, long family vacations, and the peace of mind that comes from being truly self-sufficient. Instead of constantly planning your route around the next available water spigot, you can actually focus on the destination itself.
This kind of capacity opens up a world of possibilities. You can venture deeper into national forests or settle in for a long festival weekend without the nagging worry of running dry. For anyone just starting out on this journey, having a practical guide to self-sufficiency is invaluable, and managing your own water is a huge part of that.
Why This Upgrade Matters
The appeal for bigger water tanks is definitely growing, and it reflects a larger trend in the RV community. In the booming RV water tank market, which is already valued at a staggering $2,128.7 million, the 100-gallon tank is the undisputed heavyweight champ for mid-to-large-sized rigs. North America is leading the charge, fueled by over 11 million RV-owning households in the U.S. alone who are demanding tanks that can keep up with their thirst for extended travel.
Think of this guide as your trusted resource for making this leap. I'm going to walk you through everything you need to know before you commit to what is, admittedly, a pretty significant upgrade.
- Understanding the Real-World Impact: We'll get into the critical math of weight and space.
- Making a Smart Investment: You'll learn the pros and cons of different tank materials.
- Ensuring a Successful Project: I'll cover the details on installation and long-term care.
This upgrade is about more than just water. It's about reclaiming your time and unlocking a new level of freedom on the open road. It’s a direct investment in your travel lifestyle.
Of course, being truly ready for off-grid adventures means managing your power, too. Once you've got your water situation figured out, make sure to check out our guide on choosing the https://news.rvupgradestore.com/best-rv-battery-for-boondocking/ to ensure your entire system is ready for the long haul.
Is a 100 Gallon RV Water Tank Right for You?
Deciding to install a 100-gallon water tank is a serious upgrade, and it’s easy to get caught up in the idea that bigger is always better. But before you pull the trigger, you’ve got to be honest about how you actually travel. This isn't a one-size-fits-all solution; what’s a game-changer for one RVer could be a massive headache for another.
The key is to look past the shiny appeal of huge capacity and really dig into your real-world needs. Think of it like buying a new tow vehicle—you wouldn't buy a one-ton dually just for weekend trips to the local state park, right? The same logic applies here.
Matching the Tank to Your Travel Style
Let's break down a couple of common scenarios. Imagine a family of four heading out for a week of boondocking in a national park. They've got very different water needs than a solo RVer who works remotely from their camper van.
The family is going to burn through water with daily showers, cooking big meals, and washing a mountain of dishes. Meanwhile, the solo traveler is probably focused on making every drop last to extend their stay off-grid.
The right tank size isn’t about having the most water; it's about having the right amount for the adventures you actually take. Over-sizing can lead to wasted space, unnecessary weight, and even stale, funky-tasting water.
To figure out if 100 gallons is your sweet spot, you need to do a little back-of-the-napkin math based on your own habits.
Calculating Your Water Consumption
So, how long will 100 gallons really last? The answer comes down to your personal usage, which usually falls into two camps: conservative or normal.
- Conservative Usage: This is the boondocker's bible. We're talking "navy showers" (water on to get wet, off to soap up, on again to rinse), reusing dishwater for the first toilet flush, and generally being mindful of every single drop. This is how you maximize your time in the wild.
- Normal Usage: This is a lot closer to how you'd use water at home. Think longer showers and not stressing over every drop that goes down the drain. It's definitely more comfortable, but it'll drain your supply much faster.
On average, most RVers use about 6 gallons of water per person per day. For a solo traveler, a 100-gallon tank could stretch for over two weeks with careful use. That same tank might only last a family of four about 4-5 days if they're using water normally.
This versatility is why the 100-gallon tank is such a popular DIY upgrade. It offers enough water for 5-10 days of moderate use for most couples or small families in a travel trailer or motorhome. For anyone heading to a festival like Burning Man where water is gold, this capacity is non-negotiable. It's also worth noting that industry benchmarks show this upgrade can bump an RV's resale value by 5-8%. For a deeper dive into these trends, check out the market analysis from Strategic Revenue Insights.
Before you decide, it helps to see a practical breakdown of how long your supply might last.
How Long Will 100 Gallons Last?
This table gives you a rough idea based on who's traveling and how they're using water. Think of it as a starting point for your own calculations.
| Traveler Profile | Conservative Usage (Days) | Normal Usage (Days) | Common Activities |
|---|---|---|---|
| Solo Traveler | 14-16 Days | 7-10 Days | Quick showers, washing single dishes, minimal toilet flushing. |
| Couple | 7-8 Days | 4-5 Days | Daily navy showers, cooking two meals a day, regular dishwashing. |
| Family of Four | 3-4 Days | 2-3 Days | Multiple short showers, cooking large meals, frequent dishwashing. |
As you can see, your habits make a massive difference. A family of four living like they're at home will find 100 gallons doesn't last nearly as long as they might think.
The Honest Pros and Cons
A smart decision means looking at both sides of the coin. While the freedom of a huge water tank is tempting, the trade-offs are real and shouldn't be ignored.
Potential Pros:
- Extended Boondocking: This is the big one. Stay off-grid for a week or more without the constant stress of finding your next water fill-up.
- More Convenience: Fewer trips to the spigot at the campground means more time kicking back and actually enjoying your trip.
- Peace of Mind: Nothing beats the confidence of knowing you have plenty of water, especially when you're deep in the backcountry.
Potential Cons:
- Massive Weight Gain: Water is incredibly heavy. A full 100-gallon tank adds over 830 pounds to your rig. That's a huge hit to your payload capacity and will absolutely impact your RV's handling and fuel economy.
- Loss of Storage: These tanks aren't small. You're going to sacrifice a significant chunk of valuable real estate in your RV's underbelly or basement storage.
- Water Stagnation: If you aren't cycling through that water regularly, it can go stale or develop an off taste. A larger tank often means more frequent sanitizing to keep things fresh.
Ultimately, the choice comes down to weighing these factors against how you and your family camp. Be realistic, and you'll make the right call for your rig.
Polyethylene vs. Stainless Steel Tank Materials
When you’re picking out a 100-gallon water tank, the material is one of the biggest decisions you'll make. It’s a choice that directly hits your RV's weight, your wallet, and even how your water tastes. In the RV world, it really boils down to two main players: polyethylene and stainless steel. Each one has its own personality.
Think of a polyethylene tank like a modern, high-tech piece of hiking gear. It's lightweight, surprisingly tough, and built to flex and absorb shocks without cracking. This makes it an incredibly practical and affordable option for the bumps and rattles of life on the road.
A stainless steel tank, on the other hand, is more like classic cast-iron cookware. It’s the premium choice—incredibly long-lasting and offering superior purity, but it comes with a much higher price tag and a whole lot more heft. Getting a handle on these practical trade-offs is the key to picking the right one for your rig.
The Lightweight Champion: Polyethylene
Polyethylene, which you’ll often hear called "poly" or just plastic, is the go-to material for RV water tanks, and for good reason. These tanks are made using a process called rotational molding, which creates a seamless, one-piece container that’s highly resistant to cracks and leaks.
For any RVer, the biggest win here is the low weight. An empty 100-gallon poly tank might only tip the scales at 30-50 pounds—a tiny fraction of its steel counterpart. That’s a massive benefit when you're trying to keep your RV's payload in check, leaving you more capacity for your gear, supplies, and, of course, the water itself. Poly tanks also hold up great against the constant vibration and occasional knocks that come with travel.
But, there are a couple of things to keep in mind:
- Taste and Odor: While modern food-grade plastics are way better than they used to be, some new tanks can give the water a slight "plastic" taste at first. This usually disappears after a few good cleanings.
- Durability: It’s strong, but a severe impact from road debris could potentially puncture a poly tank. This makes proper mounting and protection really important.
The Premium Choice: Stainless Steel
Stainless steel tanks are the top-shelf option for RV water systems, period. Their number one benefit is taste neutrality; water stored in steel tastes exactly like water, with zero risk of picking up flavors from the tank. They are also exceptionally durable and can last for decades if you take care of them.
The major downside is weight. A stainless steel tank of the same size can weigh 150 pounds or more when it's empty. That's a huge penalty before you even add the 834 pounds of water. All that extra mass eats directly into your Cargo Carrying Capacity (CCC), which can be a deal-breaker for a lot of RVs that are already pushing their weight limits. The cost is also significantly higher, often several times what you'd pay for a similar polyethylene tank.
The decision between poly and steel often boils down to a simple question: Are you prioritizing weight and budget, or are you aiming for the absolute best in durability and water purity, no matter the cost?
To help you figure out which material makes sense for your RV setup, this decision guide breaks down the key factors like travel style, weight capacity, and available storage space.
This flowchart simplifies the choice by connecting your personal camping habits and your rig’s limitations directly to the best tank material for you.
Food-Grade Materials Are Non-Negotiable
No matter which material you’re leaning toward, one thing is absolutely critical: the tank must be rated for potable water. Look for certifications like NSF/ANSI 61, which guarantees the material is safe for drinking water and won't leach harmful chemicals.
Never, ever repurpose a tank that was designed for waste (black or grey water) or industrial chemicals. Your family's health is on the line, making a dedicated, food-grade fresh water tank the most important spec to check before you buy.
The Critical Math of Weight and Space in Your RV
Upgrading to a 100-gallon water tank sounds great in theory, but this is where the dream meets the hard reality of your RV’s limits. Before you even touch a single fitting or hose, you’ve got to tackle the two things that will make or break this project: weight and space. The math is simple, but getting it wrong can be dangerous for you and your rig.
Water is deceptively heavy. Here’s the number you need to burn into your memory: 8.34 pounds. That’s how much a single gallon of water weighs. So, when you fill a 100-gallon tank, you're adding a whopping 834 pounds to your RV. That's not just a small addition; it's like having three or four extra adults riding along with you everywhere you go.
Calculating Your RV's Weight Limits
Every RV has strict weight limits set by the manufacturer. Pushing past these isn't just a bad idea—it can lead to brake failure, tire blowouts, and serious suspension damage. To figure out if your rig can handle the extra load, you need to find its Federal Certification Tag. It's usually a sticker on the driver’s side door jamb or near the front of a trailer.
On that tag, you're looking for a few key numbers:
- Gross Vehicle Weight Rating (GVWR): This is the absolute maximum your RV can weigh, period. It includes the rig itself, all your gear, passengers, and fluids. You can never exceed this number safely.
- Unloaded Vehicle Weight (UVW): This is what your RV weighed when it rolled off the factory floor—no cargo, no water, no passengers.
- Cargo Carrying Capacity (CCC): This is the magic number. You get it by subtracting the UVW from the GVWR. The CCC is the total weight of everything you're allowed to add: your clothes, food, camping chairs, and, of course, that big tank of water.
Think of your RV's Cargo Carrying Capacity as your weight budget. The 834 pounds of water, plus the weight of the tank itself, is a major withdrawal from that budget.
The True Weight Impact on Payload
Don't forget, the tank itself adds to the total weight. As we've discussed, modern polyethylene tanks have a huge advantage here over stainless steel. A poly tank from a trusted brand like Lippert or Husky might weigh just 50-70 pounds empty. Compare that to a steel tank, which can easily top 200 pounds. For anyone doing a DIY install, that lighter weight is a massive plus and can save you hundreds in labor costs. You can check out these automotive industry insights to learn more about how newer, lighter designs are changing the market.
To put it in perspective, let's break down exactly how much of your payload a 100-gallon tank system will consume.
100-Gallon Tank Weight Impact on RV Payload
| Component | Polyethylene Tank (Approx. Weight) | Stainless Steel Tank (Approx. Weight) |
|---|---|---|
| Empty Tank | 50 lbs | 175 lbs |
| Water (100 gal) | 834 lbs | 834 lbs |
| Total Weight Added | ~884 lbs | ~1,009 lbs |
As you can see, you're giving up between 884 and 1,009 pounds of your precious Cargo Carrying Capacity. Make sure your RV can handle it before you buy.
Measuring for the Perfect Fit
Once you’ve confirmed you have the payload to spare, it’s time to grab the tape measure. You need to find a suitable home for your new tank, and that means getting exact measurements of any potential spots.
- Underbelly Compartments: Many travel trailers and fifth wheels have open bays between the frame rails. This is often an ideal location.
- Basement Storage: Class A motorhomes and larger fifth wheels sometimes have pass-through basement storage that might have the perfect spot.
When you're measuring, don't just check the length and width. Height is critical. Look for any cross-members, wiring harnesses, or existing plumbing that could get in the way. Always leave a little wiggle room—you don't want the tank jammed in so tight that it's rubbing against a sharp edge.
Finally, consider the tank's shape. While most are simple rectangles, you can find L-shaped tanks or even custom configurations that might work better for your space. Mapping out your options first will help you find a 100-gallon water tank that not only fits your RV but also keeps you safe and balanced on the road.
A Practical Guide to Tank Installation and Plumbing
Alright, you've done the homework and have your shiny new 100-gallon water tank ready to go. Now it’s time to get our hands dirty and move from planning to practice. I know the installation can look a little intimidating, but once you understand the core components and how they fit together, it’s much more straightforward than you might think.
This isn't some dense engineering manual. Think of it as a clear overview to give you the confidence to tackle this yourself or, at the very least, have an intelligent conversation with a professional installer. The goal is simple: create a secure, leak-free system that delivers fresh water whenever you need it. Your tank is the heart of your RV's plumbing, and everything else connects back to it.
Understanding the Four Key Ports
Every fresh water tank, big or small, has four essential connection points, and each has a specific job. Getting these right is the absolute foundation of a reliable water system.
- Water Inlet (Fill Port): This is the entry point for fresh water. It’s usually a wider diameter connection, around 1.25 to 1.5 inches, that hooks up to your RV's gravity fill hatch on the side of your rig.
- Water Outlet (Pump Suction): Tucked away at the bottom of the tank, this port feeds water directly to your RV's water pump. It’s typically a smaller 0.5-inch threaded fitting where your main water line starts its journey.
- Vent Line: This little port is a huge deal. It allows air to escape as the tank fills up and lets air in as you use water. Without a proper vent, you could cause the tank to swell and buckle, or worse, create a vacuum that starves the pump.
- Drain Port: Also located at the bottom, this port lets you completely empty the tank for cleaning, sanitizing, or winterizing your RV.
Beyond the plumbing, making sure the tank itself is secure is just as critical. It needs to be mounted on a flat, stable surface and strapped down tight. Remember, a full 100-gallon tank is a massive amount of weight, and the last thing you want is that beast shifting around while you're cruising down the highway.
Choosing the Right Fittings and Seals
Connecting your plumbing lines involves a bit of hardware know-how. Most RV tanks use NPT (National Pipe Thread) fittings. These are tapered, which means they create an incredibly tight seal as you screw them in. You'll also be working with PEX connectors, which have become the standard in modern RVs because they're flexible and super easy to work with.
A leak-free seal is non-negotiable. I can't stress this enough: use plumber's tape (also called Teflon tape) or a good pipe thread sealant on every single NPT connection. This is what prevents those slow, annoying drips that can lead to water damage and a whole lot of frustration. Take your time with each connection—get it snug, but don't go overboard and crack the plastic fittings. If you want to dive deeper into the heart of the system, check out our guide on how RV water pumps work.
A successful installation lives or dies in the details. One single, poorly sealed fitting can ruin the whole project and leave you with leaks and headaches. Double-check every connection before you pack up your tools.
The Essential Upgrade: Tank Sensors
If you’re going through the trouble of installing a new tank, do yourself a huge favor and upgrade the monitoring system while you're at it. The standard factory-installed sensors are notoriously inaccurate. They often rely on just three or four probes stuck inside the tank, giving you vague readings like "1/3," "2/3," or "Full"—which is next to useless.
With a massive 100-gallon water tank, that level of guesswork just doesn't cut it. You don’t want to be caught mid-shower when the water suddenly stops, even though the monitor said you had a third of a tank left.
This is where modern sensors completely change the game. Systems like the SeeLevel II Tank Monitor are a massive leap forward. Instead of probes inside the tank, they use sensor strips that stick to the outside, providing precise readings in percentages or gallons. You get a real-time, accurate look at exactly how much water you have, letting you plan your usage with total confidence. Installing one during the initial tank setup is the easiest time to do it and, in my opinion, one of the most valuable upgrades any serious RVer can make.
Keeping Your 100 Gallon System Clean and Safe
Having a 100-gallon water tank gives you a ton of freedom on the road, but with that much water comes a little responsibility. Think about it—a large volume of water just sitting there can become a perfect home for bacteria if it's not looked after.
The good news? Keeping your system clean, safe, and ready for your next adventure is pretty simple once you get into a routine. It’s all about staying ahead of the game with proactive maintenance rather than waiting for a problem to pop up. This means sanitizing your tank regularly, doing quick inspections, and properly winterizing the whole system before temperatures drop. Taking these steps not only protects your investment but ensures the water you're using is always fresh and clean.
Sanitizing Your 100 Gallon Water Tank
Sanitizing your fresh water system is probably the most important maintenance job on your list. It clears out any bacteria, algae, or other gunk that can build up over time, especially when it’s warm out. I recommend doing this at least twice a year: once when you de-winterize in the spring, and again mid-season if your RV has been sitting unused for a bit.
The whole process is straightforward and just uses a bit of household bleach. The trick is getting the mixture right so it’s strong enough to clean effectively without leaving a swimming pool taste in your water.
Sanitization Steps for a 100-Gallon Tank:
- Drain the System: First things first, completely drain any old water from your fresh tank and your hot water heater.
- Mix the Solution: For a 100-gallon tank, you’ll need exactly one full cup (8 ounces) of plain, unscented household bleach. Mix that cup of bleach with a gallon of water before you pour it into the fresh water fill port—this helps it disperse better.
- Fill and Circulate: Now, fill the tank the rest of the way with fresh water. Turn on your water pump and open every single faucet (hot and cold sides) one at a time until you can smell the bleach. This pulls the sanitizing solution through all your plumbing lines.
- Let It Sit: Leave the solution to do its work in the tank and lines for at least four hours. If you want a really deep clean, you can let it sit for up to twelve hours.
- Drain and Flush: Time to drain the whole system again. Then, refill the tank with fresh water and flush everything out by running all the faucets until the bleach smell is gone. You might need to fill and flush two or three times to get rid of the chlorine smell and taste completely.
Ensuring the purity of your water source is a cornerstone of safe RVing. Regular maintenance and proper techniques are essential for keeping your water clean, so understanding how to purify water is vital for any tank owner.
Your Winterization Checklist
If you live or travel anywhere that sees freezing temperatures, winterizing your rig isn't optional. When water freezes, it expands, and that expansion is powerful enough to crack your tank, burst pipes, and ruin your water pump. Trust me, it’s a recipe for thousands of dollars in repairs you don’t want to deal with.
The goal is simple: get every last drop of water out of the system. Here’s a quick checklist I follow every year:
- Drain Everything: Completely empty your 100-gallon fresh tank, your grey and black tanks, and your hot water heater. Don't forget to open the low-point drains to get the water out of the lines.
- Bypass the Water Heater: Find your water heater’s bypass valve and switch it. There’s no point in filling your six or ten-gallon water heater with expensive RV antifreeze.
- Add Antifreeze: You can use an RV water pump converter kit or just pour non-toxic RV antifreeze directly into your fresh water tank.
- Circulate Antifreeze: Turn the pump on and open each faucet, one by one, until you see the pink antifreeze flowing out. Make sure to run it through the toilet and any outdoor showers, too!
For a more detailed walkthrough, check out our complete guide to RV fresh water tank sanitizing. Following these steps will make sure your water system is protected all winter and ready to hit the road come spring.
Your Top Questions About 100-Gallon Tanks Answered
Even after getting all the details, you've probably got a few questions still rattling around. I get it. Swapping in a 100-gallon water tank is a serious upgrade, and you want to be sure you've covered all the angles. This is where we'll tackle the most common questions I hear from other RVers, with straight-to-the-point answers to help you make the final call.
Think of this as your quick-reference FAQ, cutting through the noise and reinforcing the big takeaways before you pull the trigger on this project.
Will a 100-Gallon Tank Mess with My RV’s Handling and Fuel Economy?
Yes, without a doubt. And this is the one thing you absolutely cannot afford to ignore.
Adding over 830 pounds of water is going to change how your rig feels on the road—period. You’ll notice it when you accelerate, when you hit the brakes, and especially when you take a corner. It’s also going to take a bite out of your fuel efficiency.
This is why it's so critical to make sure your RV’s suspension, axles, and tires are rated for that much extra weight. A smart strategy I see seasoned RVers use all the time is to travel with the tank empty or just partially full. Then, they top it off at a campground or a potable water station right before they get to their destination. It’s a simple habit that makes a world of difference in handling and saves you money on fuel during those long hauls.
The weight of water is the easiest thing to forget and the most dangerous thing to miscalculate. Its impact on your payload and how your RV drives is very real. Planning for it isn’t optional—it’s a critical part of a safe upgrade.
How Do I Get Rid of That “Plastic” Taste in a New Tank?
Ah, the dreaded plastic taste. It’s a super common issue with new poly tanks, but the good news is, it’s an easy fix. That off-taste is just from leftover residue from the manufacturing process. The best way to knock it out is to give your new 100-gallon water tank a good cleaning and sanitizing before its first real use.
Here’s a simple process that works every time:
- Mix up a solution of baking soda and water. A good rule of thumb is about one cup of baking soda for every 20 gallons, so for a 100-gallon tank, you’ll need five cups.
- Pour that mixture into the tank, fill it the rest of the way with fresh water, and just let it sit for a full 24 hours.
- Drain and rinse it out completely. Then, follow up with a full sanitization cycle using a diluted bleach solution, just like we covered in the maintenance section. This one-two punch almost always gets rid of any weird taste.
Can I Really Install a 100-Gallon Tank in Any RV?
Definitely not. This is one of those upgrades that is far from a one-size-fits-all deal. Whether you can install a tank this big boils down to two things you can’t compromise on: physical space and your rig’s weight capacity.
First, you need to have a spot for it. You must have a compartment in your underbelly or basement storage that can physically hold the tank without cramming it against other gear or stressing the frame.
Second, and more importantly, your RV’s Cargo Carrying Capacity (CCC) has to be able to handle the 830+ pounds of water, plus the weight of the empty tank, without pushing you over your Gross Vehicle Weight Rating (GVWR). Before you even think about buying a tank, grab a tape measure and check the weight sticker on your RV. It will tell you everything you need to know.
At RVupgrades.com, we’ve got the parts and the know-how to help you nail your next big project. From the tanks themselves to all the fittings and fancy new sensors, we stock everything you need to upgrade your fresh water system the right way.
Check out our huge selection of plumbing and fresh water gear at https://www.rvupgradestore.com.
