Autonomy is the main trump card of any camper, and it is the volume and quality of the liquid tank that determines how long you can enjoy nature away from civilization. Water tank for motorhome It is not just a vessel, but a complex unit that must withstand vibrations, temperature changes and pressure of the pump system. An error in the choice of material or shape can lead to leaks, which in a limited space turn into a disaster.
Motorhome owners often underestimate the importance of proper installation and preservation of the system, which in winter leads to rupture of pipes or deformation of the walls. In this article we will discuss why standard canisters are not suitable for stationary installation, how to calculate the required casting and what nuances are hidden in the design of modern tanks.
It is necessary to immediately decide on priorities: what is more important - the maximum volume, durability of the material or the ease of installation in a complex geometric compartment? The market offers solutions in food-grade polyethylene, stainless steel and even composites, and each option has its own strengths and weaknesses, which will be discussed later.
Materials of manufacture: polyethylene against stainless steel
The choice of material directly affects the life of the system and the safety of stored fluid. The most common option is high-density food polyethylene (HDPE). This material is inert, does not react with water and is not subject to corrosion. However, plastic has a significant disadvantage - it is sensitive to ultraviolet light and can eventually become brittle if the tank is installed in an unprotected place.
Stainless steel AISI 304 or 316 is a premium choice for those who value reliability over economy. These tanks are practically eternal, can withstand extreme temperatures and do not require special protection from rodents or mechanical damage. The weight of an empty steel tank is much higher, which is important to consider when calculating the total mass of the motorhome.
Effects of material on water taste
Plastic tanks can give water a slight taste in the first weeks of operation, especially if poor-quality polyethylene was used. Stainless steel is completely devoid of this drawback, providing a neutral taste of the liquid even during prolonged storage.
There are also composite solutions and reinforcement tanks that try to combine the lightness of plastic and the strength of metal. When choosing, pay attention to the labeling Food Gradecertifying the safety of material for contact with drinking water. Cheap technical tanks can release toxins when heated in the sun.
⚠️ Warning: Never use containers intended for process fluids (antifreeze, diesel), even after thorough washing. The structure of the plastic can store molecules of chemicals that then pass into drinking water.
Design features and shapes of tanks
The geometry of the capacity is dictated by the available space in the body of the motorhome. Manufacturers produce tanks of rectangular, cylindrical and complex L-shaped shapes for installation in wheel arches. It is important to understand that rectangular tanks When fully filled, they experience tremendous pressure on the walls, so they must have additional stiffness ribs or be made of thicker material.
Cylindrical tanks are better at distributing internal pressure and are more resistant to external loads, but they use niche usable space less efficiently. When designing a water supply system, the presence of internal partitions (wave cutters) that extinguish the splash of water when the car is moving is also taken into account.
- 🚿 Throats and hatches: Wide neck simplifies cleaning and disinfection, narrow - reduces the risk of debris when taking water from open sources.
- 🔧 Position of the pipes: The upper or lower water intake affects the pump operation and the risk of suction of sediment from the bottom.
- 🌡️ Ventilation system: The presence of an air valve is critical to prevent the tank from vacuating during emptying.
When ordering a tank for individual dimensions, always leave a technological gap of 2-3 cm on all sides to compensate for the thermal expansion of the material and the installation of vibration insulation.
Size calculation and system planning
The tank volume is a compromise between autonomy and payload. One liter of water weighs one kilogram, and a stock of 200 liters is already 200 kg, which significantly affects fuel consumption and vehicle dynamics. For a couple of people on the weekend is enough 40-60 liters, while for long trips a family of four will need at least 100-120 liters.
The volume of the hot water supply system should also be taken into account. The boiler in the motorhome usually takes 10-15 liters, which also need to be filled. If you plan to use a shower often, it makes sense to install two separate tanks: one for technical needs only (shower, washing dishes) and one small one for drinking water.
| Type of travel | Number of people | Recommended volume (litres) | Commentary |
|---|---|---|---|
| Weekends (camping) | 2 | 40-60 | Enough for showering and cooking |
| Wild tourism | 2 | 80-100 | Requires a reserve of 3-4 days |
| Family leave | 4 | 120-150 | Accounting for expenditure on children and hygiene |
| Expedition | 2-3 | 200+ | Maximum autonomy |
When planning your volume, don’t forget the 80% rule. Never fill the tank "to the end" when driving, especially if it does not have internal partitions. The water in the full tank creates a dangerous inertial mass that can shift the center of gravity of the car in a turn.
Installation and fastening: combating vibration
Installation of the tank in the motorhome requires an engineering approach. Just put a container in a niche and screw it with bolts is a sure way to get a crack in a couple of thousand kilometers. The main enemy of plastic tanks is point loads and vibration. The fastening elements must pass through reinforced eyelets or cover the body with wide ribbons with rubber dampers.
For steel tanks, anti-corrosion treatment of welding sites and contacts with the body is important. Between the metal of the tank and the body of the car must be laid a layer of vibration insulation or rubber to prevent electrochemical corrosion and paint erasure. Chomut must be made of stainless steel, as conventional galvanized quickly rust from constant humidity.
☑️ Checking the tank installation
Pay special attention to the fixation of hoses. They should not be hanging or stretching. Use corrugated tubes to protect against rubbing in places of passage through metal partitions of the body. Any movement of the tank relative to the body is unacceptable, so after the first hundred kilometers of run be sure to make a stretch of all mounts.
⚠️ Attention: The design of fasteners and the safety requirements for the carriage of goods may vary by country. Always make sure that the installed tank does not block access to emergency exits and does not act beyond the dimensions of the car.
Insulation and protection against freezing
The operation of the motorhome in winter turns water from a resource into a threat. Freezing, the water expands and tears even the most durable walls of the tank and pipes. Insulation of the tank A mandatory procedure for all-season campers. Materials based on foamed polyethylene, rubber or polyurethane foam are used.
Insulation alone is often not enough, so electrical heating elements are integrated into the system. These can be heating mats, glued to the bottom and the walls of the tank, or flow heaters in the main line. It is important to connect such systems through thermostats so as not to waste battery power at plus temperatures.
For pipes and pumping station insulation is even more important, since the thin walls of the pipes freeze instantly. It is recommended to use a heating cable, which is mounted along the pipe under a layer of thermal insulation. In critical situations, when the overnight stay is in severe frost without the possibility of heating, the tank is better to empty completely.
Comprehensive protection against freezing includes not only insulation of the tank itself, but also heating of the pump group, filters and all sections of pipes passing outside the heated cabin.
Maintenance, cleaning and conservation
Stagnant water is an ideal environment for bacteria like Legionella to multiply and produce an unpleasant odor. Even if you use the tank rarely, the water in it must be updated at least once every two weeks. To disinfect the system, conventional chlorine (sodium hypochlorite) is used in a proportion of about 50 ml per 100 liters of water, after which the system must stand for several hours.
Periodically, at least once a season, it is necessary to carry out mechanical cleaning of the tank. To do this, the bottom sediment is removed through the hatch and the walls are wiped with a brush. In hard-to-reach places, you can use a solution of citric acid to remove lime plaque, which often causes pumps to break down.
- 🧼 Disinfection: Use of specialized tablets or solutions for motorhomes.
- 🍋 Scaling removal: Washing with a weak acid solution to protect the pump.
- 💧 Plum: The presence of a drain tap at the lowest point of the tank is mandatory for complete preservation.
When setting the motorhome for winter conservation, the system should be completely drained. Blow the hoses with a compressor so that there is no water left in the bends, and leave all the taps open. This will prevent breaks in the event of accidental freezing of residual moisture.
How often should the filters be changed in the water supply?
The filters of rough cleaning (net) are washed at each filling of the tank from a doubtful source. Cartridge filters (coal, polypropylene) require replacement every 3-4 months of active use or after filling the tank 10-15 times, regardless of time.
Can I put water in the tank from a river or lake?
Technically possible, but it is highly recommended not to do so directly. Water from open water bodies contains organic matter, suspensions and bacteria that will quickly clog the pump and make the water unfit for drinking. Use only special hoses for water collection and be sure to pass the liquid through the filter funnel.
Why is the pump buzzing but the water is not coming?
Most often this is suffocation of the system or clogging of the filter-grid at the entrance to the pump. Check the water level in the tank, the tightness of the suction pipe and the condition of the prefilter. The problem can also be in the dried membranes of the pump if it has not been used for a long time.