Water tank in a motorhome: how to choose, install and maintain

Introduction: Why a water tank is a key element of a motorhome

A motorhome without a water supply system is like a house without running water: inconvenient, unhygienic and restricts freedom of movement. A water tank solves this problem by turning your camper into a full living space with shower, sink and toilet. But how to choose the right model among dozens of options? What materials are safe for drinking water, and which ones are better to avoid? And how to install the container correctly so that it does not become a source of problems?

In this article we will analyze all types of tanks — from standard plastic to premium aluminum, we’ll tell you about volumes (from 20 to 200 liters), the nuances of installation under the floor or in niches, and we will also provide a checklist for care. We will pay special attention critical installation errors that lead to water leaks or freezing in winter. If you are planning long-term trips or wintering in a motorhome, this information will save you thousands of rubles on repairs.

Types of water tanks: which one to choose for your motorhome

All tanks are divided into three main categories according to material of manufacture, and each has pros and cons. Plastic models (polyethylene, polypropylene) - the most popular due to their lightness and price, but not all can withstand frost. Metal (stainless steel, aluminum) more expensive, but stronger and more durable. Rubber or textile (for example, from Water Bladder) are suitable for temporary use, but require careful handling.

Tanks also differ in designs:

• 🔹 Hard - classic rectangular or cylindrical containers with a fixed shape. Convenient for permanent installation under the floor or in niches.
• 🔹 Soft (bladers) — flexible tanks made of durable rubber or PVC. They take up little space when folded, but require support when filling.
• 🔹 Heated — equipped with electric heaters or heat exchangers for use in winter. Relevant for northern regions.
• 🔹 Divided into zones — have partitions for separating drinking water from technical water.

When choosing, consider climatic conditions: If you drive in winter, choose insulated or heated models. For the southern regions, any tanks are suitable, but it is important that they be UV stabilized (did not collapse under the sun).

Tank volume: how much water is needed for a comfortable trip

The optimal volume depends on the number of passengers and the duration of the trip. Enough for a single traveler for a weekend 20–40 liters, and a family of 4 people will need for a week 100–150 liters. Please note that water is used not only for drinking, but also for:

• 🚿 Shower (10–15 l/min)
• 🧼 Dishwashing (5–10 l/day)
• 🚽 Toilet flush (2–5 l/use)
• 🍳 Cooking (3–5 l/day)

The table below shows recommended volumes depending on the usage scenario:

Number of people	Duration of the trip	Minimum volume (l)	Optimal volume (l)
1–2	Weekend (2–3 days)	20	40–60
2–3	Week	60	80–100
3–4	2 weeks or more	100	150–200
1–2 (winter mode)	Any	30	50–70 (heated)

⚠️ Attention: If you're traveling in Europe, be aware that many campsites have restrictions on greywater drainage. Some countries (eg Germany) require certified waste tank a volume of at least 10% of the clean water tank.

Where to install the tank: 5 proven places in the motorhome

The installation location depends on the type of tank and the layout of the motorhome. The most common options:

1. Under the floor - ideal for hard tanks. Saves space, but requires thermal insulation in cold weather. Important: the weight of water (1 l = 1 kg) shifts the center of gravity, so distribute the load evenly.
2. In the niches under the seats — suitable for tanks with a volume of up to 50 l. Convenient for quick access, but reduces usable space.
3. On the roof — relevant for soft bladers or additional containers. Requires reliable fastening and protection from UV rays.
4. In the luggage compartment - optimal for vans. The tanks are attached to the walls using brackets.
5. In special cabinets — for premium motorhomes with factory preparation for water supply.

When installing, follow the rules:

• 🔧 Attach the tank at least 4 points (for containers from 50 l).
• 🔧 Use vibration-absorbing pads (for example, made of rubber or silicone) to avoid rattling when moving.
• 🔧 Lay pipes with a slope 2–3° for gravity drainage.
• 🔧 Check the tightness of connections under pressure (fill the system and leave for 24 hours).

⚠️ Attention: If you are installing the tank on the roof, avoid models with a flat bottom - they can become deformed under the weight of the water. The best option is containers with stiffening ribs or cylindrical shapes.

Connecting the tank: diagram and step-by-step instructions

The water supply system of a motorhome consists of 4 key elements:

1. Clean water tank (main capacity).
2. Pump (submersible or surface, for example, Shurflo 12V).
3. Pipeline (usually PVC or silicone hoses diameter 12–16 mm).
4. Wiring (faucets, shower, sink).

Step-by-step instructions for connection:

1. Place the tank in the chosen location and secure it.
2. Connect suction hose to the pump. Use a check valve to prevent water from flowing back.
3. Pave pressure hose from the pump to the disassembly points (sink, shower).
4. Install coarse filter in front of the pump (protects from sand and debris).
5. Connect the pump to 12V or 220V (depending on model).
6. Check the system for leaks by filling the tank with water and turning on the pump.

For winter use, add to the diagram:

• ❄️ Heating cable (for example, FrostKing) along the pipes.
• ❄️ Thermal insulation tank (polyurethane foam or foil insulation).
• ❄️ Drain tap at the lowest point of the system.

What to do if the pump does not pump water?

Check the voltage at the pump terminals (should be 12V). Make sure the check valve is not stuck. Inspect the coarse filter - it could be clogged. If the pump hums but does not pump, the impeller may be burnt out or the shaft may be jammed.

Maintenance and cleaning: how to extend the life of your tank

Even the best quality tank will not last long if you do not take care of it. Basic rules:

• 🧼 Clean the tank every 3 months (or after a long period of inactivity). Use special means, for example, Camco TastePURE or vinegar solution (1:10).
• 🦠 Disinfect 2 times a year chlorine solution (1 tablespoon per 10 liters of water) or cleaning tablets (AquaTab).
• ❄️ Drain the water before wintering, if the tank is not heated. Residual liquid may rupture the container when it freezes.
• 🔍 Check the seals taps and connections for wear. Rubber gaskets lose their elasticity after 2–3 years.

For cleaning, follow the algorithm:

1. Drain all water from the tank.
2. Pour in the cleaning solution and leave for 12 hours.
3. Rinse the container with clean water 2-3 times.
4. Dry the tank (you can use a hairdryer or in the sun).

⚠️ Attention: Never use to clean the tank household cleaning products (for example, Fairy or Domestos) - they leave a film that spoils the taste of water and can be toxic. Use only certified compositions for drinking systems.

Top 5 mistakes when operating a water tank

Even experienced campers sometimes make mistakes that lead to damage or discomfort. Here are the most common:

1. Ignoring water weight. A 100-liter tank weighs 100 kg - this is critical for unloading the axles. Always check permissible load your motorhome.
2. Lack of ventilation. Closed tanks without a valve can become deformed due to changes in pressure (for example, when water is heated by the sun).
3. Using non-certified hoses. Cheap PVC hoses crack over time and release plastic odors into the water.
4. Freezing of water in pipes. Even at −5°C, unprotected pipes can burst. Always drain the water or use heat.
5. Storing water longer than 2 weeks. Stagnant water “blooms” - bacteria multiply in it. Change the water regularly or use silver ionizers.

To avoid problems, follow a simple rule: "Check the system before every trip". Taking 10 minutes to inspect the tank, pipes and pump will save you hours of repairs down the road.

FAQ: answers to frequently asked questions

Is it possible to use a process water tank for drinking water?

No, unless the tank is certified for potable water. Technical containers may contain toxic additives (for example, antistatic agents or plasticizers) that are released into the water. Look for markings "Drinking Water Safe" or "NSF/ANSI 61".

Which pump is better: submersible or surface pump?

Submersible pumps (for example, Jabsco Par-Max) quieter and more efficient for large tanks, but more difficult to install. Superficial (for example, Shurflo Revolution) are easier to install, but noisier and require protection from moisture. For tanks up to 50 liters, any option is suitable.

What to do if the water in the tank starts to smell?

Drain the water, rinse the tank with a vinegar solution (1:10) or a special product (AquaClean), then rinse. If the smell remains, check the hoses - often the problem is in them. For prevention, use silver ionizers or preservation tablets.

How to insulate a tank for the winter?

Wrap the tank thermal insulation material (for example, ArmaFlex) 20–30 mm thick. Route along the pipes heating cable (power 10–15 W/m). Install thermostat to automatically turn on heating at +5°C. Don't forget about ventilationto avoid condensation.

How much does a motorhome tank cost?

Prices depend on material and volume:

• Plastic tank 40–60 l: 3 000–8 000 ₽.
• Metal tank 80–100 l: 15 000–30 000 ₽.
• Soft blader 50–100 l: 5 000–12 000 ₽.
• Heated system: from 25,000 ₽.

Additionally, the budget will be spent on a pump (5 000–15 000 ₽), hoses and fittings (2 000–5 000 ₽).