Water is an essential component of any van build, and choosing the right type of water tank can have a significant impact on the comfort and convenience of your van life. Before selecting an individual tank or style, consider factors like your available space, number of people using it, types of needs, durability, and cost. Once you’ve narrowed down your use case, there are a few main categories of water tanks, with several types within that are available for van builds, each with its own advantages and disadvantages. The three main categories of water tanks for van builds are freshwater tanks, gray water tanks and black water tanks. The types of tanks within vary by category.
Freshwater tanks
Freshwater tanks are a crucial component of a van build for those who want to have access to potable water while on the road. These tanks are used to store fresh water for drinking, cooking, and cleaning. The size of the freshwater tank will depend on the size of the van, as well as the number of people using the system.
There are two main types of freshwater tanks: portable tanks and permanent tanks.
Portable / small tanks
Portable tanks are smaller and can be easily removed from the van for filling and cleaning. They are also great for those who want to minimize the amount of space taken up by the freshwater system when it is not in use. Portable freshwater tanks typically range in size from 1 gallon to 7 gallons. Portable tanks are incredibly convenient, cheap and easy to manage. Many people even forgo a comprehensive plumbing system by using a portable tank or jug, with an appended portable battery powered pump. Examples of portable tanks include the 5 gallon water jugs (often blue), jerry cans and typical rectangular rigid, but smaller tanks.
Permanent / large tanks
Permanent freshwater tanks are usually larger and can hold anywhere from 10 to 50 gallons or more of fresh water. Given the size, these tanks are sometimes installed underneath the van, but it depends on your build and needs - for instance, are you a weekend warrior? Will you be in a cold climate?. The rigid tanks for freshwater are often made with different materials and features than those intended for gray or blackwater. Permanent tanks are typically made of either plastic or stainless steel. Plastic tanks are more affordable and lightweight, while stainless steel tanks are more durable and resistant to UV rays. Most vanlifers tend to opt for the plastic / synthetic material given the weight differential vs. metal, and cost. If choosing a plastic or similar material for your fresh water supply, be sure to confirm the material used is safe for fresh and drinking water. Consider whether it's BPA Free or NSF certified, and whether it complies with FDA guidelines.
There are also several different shapes of freshwater tanks available. The most common shape is rectangular, which is great for fitting into tight spaces. Round tanks are also available, which can help to minimize the amount of wasted space in the van. Some tanks will be a pure rectangle, while others will have grooves and contour for an undermount fixing. Some may even be designed to fit around a wheel well. Finally, some freshwater tanks are custom designed to fit into irregularly shaped spaces, which can be helpful in vans with unconventional layouts - these are typically quite expensive, but convenient to help optimize space in a custom van build.
Fresh water tanks are typically non-pressurized, meaning that they are vented. If the tank you purchase isn’t vented by default, it’s simple enough to create an opening to relieve pressure. Depending on the vendor, the tank may come with spouts that are compatible with standard plumbing fittings. Keep in mind you’ll may need a few access points on your freshwater tank: 1) pressure vent, 2) water input, 3) water output and potentially a port for draining water. Depending on the complexity of your water system, you may combine some of these, or not need all of them - but be aware that many standard freshwater tanks could come with all four.
Bladder water tanks
While we don’t see them as commonly used in vanlife as rigid tanks, bladder tanks are a unique type of freshwater tank that are designed to be flexible and collapsible. These tanks are made of a durable plastic or nylon material and can be filled with water and then collapsed when not in use. This makes them a great option for those who want to minimize the amount of space taken up by their freshwater system when it is not in use. While less common for full-time van-builds due to durability concerns, these could be a worthwhile option to explore for part-timers, or those without a complex or comprehensive water system.
Bladder tanks come in a variety of sizes, ranging from 10 gallons to 100 gallons or more. They are typically kept inside the van, as suspending underneath would be liable to damage / breaking. It is important to note that bladder tanks can be more susceptible to punctures and leaks than traditional rigid tanks, so care should be taken when installing and using them.
Gray water tanks
Gray water tanks are used to collect and store waste water from sinks, showers, and other sources. If you have a full or even partial water system with a sink, shower or any sort of water output, it is important to have a gray water tank in your van build. Depending on the region, this may be required in order to comply with environmental regulations, as it is often illegal (or unethical) to simply let gray water release on the ground in most areas. When purchasing soaps and materials that will mix with your water use, consider buying all natural products for ease of mind with your gray water contents. Many campgrounds, RV parks, and public utilities offer dumping stations. Campgrounds also have dedicated sewer connections that could be used. Some regions and locations may allow the dumping of gray water within a particular distance from natural resources like rivers and public areas, but be careful about regulations here - research directly and use good judgment.
Gray water tanks can range in size from 5 gallons to 25 gallons or more, depending on the size of the van and the number of people using the system. Similar to freshwater tanks, you can find them in a range of sizes and materials. Compared to freshwater tanks, gray water tanks are often suspended underneath the van to reduce potential contamination, leakage, mess or smell. The characteristics of a gray water tank do not differ largely from a freshwater tank. You’ll likely see many options with spouts, opening and standard fittings designed into the tank interface. While many gray water tanks may also be BPA free, FDA compliant, NSF certified, and more - your concerns may be limited given that you won’t be drinking or interacting with this tank in any way. As you’ll simply be using it to collect and drain water, you probably won’t need to be as thoughtful as to these types of characteristics.
Black water tanks
Black water tanks are used to store waste from the toilet. These tanks are a necessity if you plan on having a toilet in your van build that uses water. Black water tanks can range in size from 5 gallons to 25 gallons or more, depending on the size of the van and the number of people using the system. Black water tanks are typically made of plastic, which is lightweight and easy to install. However, some higher-end van builds may opt for stainless steel black water tanks. Often for vanlife, we see builds incorporate composting and non-water based toilet solutions in order to avoid using a black water tank because having 3 tanks on-board takes up a lot of space. Black water tanks also require a higher degree of effort to responsibly dump, and carry a higher risk for adverse leakage. Black water often has elevated requirements and regulations surrounding disposal; campgrounds will similarly be a great spot, but there are plenty of resources and websites like rvdumpsite.net that can help you find a responsible dump ground.
Combination tanks
While we do not see as commonly in DIY vans, combination tanks are a great option for those who want to minimize the amount of space taken up by their freshwater, gray water, and black water systems. These tanks are designed to store all three types of water in one unit, which can help to save space and simplify the plumbing system. Combination tanks can be made of plastic or stainless steel and can range in size from 10 gallons to 40 gallons or more, depending on the size of the van and the number of people using the system.It is important to note that combination tanks require careful maintenance and cleaning, as the different types of water stored in the tank can lead to contamination and potential health risks if not properly managed. Some combination tanks also include a built-in filtration system to help keep the water clean and potable.
In conclusion, there are several types of water tanks available for van builds, each with its own advantages and disadvantages. When choosing a water system for your van build, it is important to consider factors such as space limitations, the number of people using the system, and the types of activities you will be using the water for. With careful planning and installation, a high-quality water system can help you stay comfortable and healthy on the road.