How Much Water Do I Actually Need in a Van?
A Realistic Guide to Gallons Usage and Weight
One of the most common questions in vanlife is how much water is enough. The instinct is to install the biggest tank possible, but more water does not always mean more freedom.
This guide breaks down realistic daily usage, how tank size affects weight and layout, and how to choose capacity based on how you actually live in your van.
Why Most People Overestimate Their Water Needs
Most first time van builders assume they will use far more water than they actually do. In practice, habits change quickly in a small space and most people become efficient without feeling deprived. For example, I spent the last summer as a 22 year old in a campervan solo, with a 19-gallon water tank and averaged four showers per fill, while also brushing my teeth and washing my hands regularly.
What Uses the Most Water in a Camper Van
Showers are by far the biggest water consumer in a van. A surprising amount comes from sinks, brushing teeth, and hand washing too. One of the best ways to save water is to fill your sink to do dishes, instead of running the water like you would at your house.
Typical Daily Water Usage in Vanlife
Daily water usage varies widely, but most full time vanlifers fall into a narrow range.
Many solo travelers use 2 to 3 gallons per day without showers. With regular showers, usage often increases to 4 to 6 gallons per day. If you plan to use a Brita water bottle or water filtration to provide drinking water then your consumption can increase as well.
How Long Common Tank Sizes Last
Tank size only matters in relation to how you use water.
A 10 to 15 gallon tank typically lasts 2 to 4 days.
A 20 to 24 gallon tank often lasts 5 to 7 days.
A 30 to 36 gallon tank may 8-12 days with conservative use.
These estimates assume normal sink use and occasional showers.
Real World Full Time Vanlife Example
As mentioned above, I live in a campervan full time, and although my shower is winterized now, in the summer I showered 4-5 times using the Tetravan folding shower and used my sink regularly. Another important thing to note here is that showering in a van is “showering in a van.” The hose is often stopped to scrub your soap on and and then turned back on to spray off. Water is realistically only running for 3-4 minutes per shower.
With efficient showers and daily sink use, this often allows 4 to 5 showers per week and weekly refills.
Why More Water Is Not Always Better
Water adds significant weight to your build. If you are an RVIA Certified builder this can be a huge challenge. Water tanks can also be a huge defining constraint, as they are a must to have in your build but often are challenging to design bed systems and galleys around. In this scenario, bigger is not always better for your layout.
Each gallon weighs about 8.3 pounds, so oversizing tanks can quietly add hundreds of pounds that affect fuel economy and handling.
How Tank Size Affects Van Layout
Larger tanks require larger cabinets and more interior space. Tanks are typically a primary factor in a van layout and determined at the start of the build. NW Conversions offers a variety of water tanks as well as a water tank configurator to help you determine which tank will fit in the desired space of your van.
In general, smaller tanks, like the 10 gallon and 20 gallon galley tanks, allow more flexible layouts, better storage, and easier access to plumbing for maintenance.
Fresh vs Gray Water Balance Matters More Than Total Gallons
Running out of gray capacity often happens before running out of fresh water, which can be frustrating or cause an overflow. Balanced tank sizing reduces dumping frequency and prevents water system frustration. It’s still best to have more fresh than grey so you can store water like a camp off grid. Think about where you are going, you can easily dump grey water on the road, but you can’t easily find new water sources while dispersed camping.
How Showers Change Water Requirements
Adding a shower dramatically increases water usage and it’d be ideal to at least consider a larger water tank if you have the room. A suggestion would be to opt for 20+ gallon tank capacity, but if you are a solo traveler you may get away with the 20 gallon water tank. A 24 gallon centered tank and 36 gallon centered tank are some of our most popular used tank options.
If daily showers are important to you, you either need larger tanks, careful rationing, or a recycling shower system that reduces water consumption.
How Recycling Showers Reduce Water Needs
Recycling showers allow long showers using very little water by recirculating fresh water on a closed loop and filtering it and sanitizing the water with UV light. This setup allows smaller fresh and gray tanks to support daily showers without frequent refills.
Weight and Resale Considerations
Heavier builds are harder on suspension components and can reduce resale appeal. Also, heavier vans have a lower mileage which further decreases resale value. There is a natural desire for larger water tanks, so as long as you have a lightweight build in general, it’s great to have more water capacity.
Climate and Travel Style Considerations
Cold weather travelers often prefer smaller interior tanks that are easier to protect from freezing and less hassle to dismount in winter time or ski-season. Similar to electrical systems, it’s important to have heating in your van to keep interior tanks from freezing and causing damage to your plumbing lines and hoses. As part of the winterization process, you should drop your exterior tanks, empty your wheel well tanks, and blow out the lines. If you have a 4 seasons van, you should have an answer for your interior tanks that includes tank heating pads or a hydronic floor that keeps tanks warm.
If you are in California or a warmer weather traveler you can tolerate larger exterior tanks for fresh and grey tanks. You should have few issues with freezing tanks, and if you are concerned, there are tank heating pads on the market that work well.
Builder Recommended Fresh Water Tank Sizes
Based on real world usage, many builders recommend:
Weekend or minimalist builds:
10 to 15 gallons
Solo full-time vanlife:
20 to 24 gallons
Couples or frequent showers:
30 to 36 gallons
These are starting points, not rules.
Final Thoughts on How Much Water You Need
The right tank size depends on how you live and what features you want in your van. Be conscious of weight, layout, and fresh grey capacity parity.
