8 Septembre 2026

Reverse Osmosis: Which Tank Should You Choose?

A reverse osmosis unit can produce water suitable for a wide range of industrial applications. However, between production and use, the treated water often needs to be stored in a tank suited to the characteristics of the installation.

Choosing a reverse osmosis water storage tank is therefore about more than simply determining the required capacity. The material, sealing system, roof configuration, equipment, operating conditions and site constraints all need to be considered from the design stage onwards.

For industrial operators, working with a specialist manufacturer makes it possible to size a solution that is consistent with the entire process and with the requirements for storing the water produced.

Key Takeaways

The tank provides a buffer volume between water production and consumption.
The choice of material and sealing system must take into account the water quality and intended use.
Sizing depends on production flow rate, consumption patterns and site operation.
A bolted steel tank can meet the requirements of many industrial projects thanks to its modular design.
APRO Industrie supports industrial operators with the design, manufacture and installation of tanks suited to storing different water qualities.

Why store water after reverse osmosis?

The output of a reverse osmosis unit and the water consumption of an industrial site do not necessarily follow the same pattern.

The treatment unit may produce water continuously, while process demand varies according to operating hours, production cycles or the requirements of different pieces of equipment.

Reverse osmosis water storage creates a buffer capacity between production and consumption. It helps ensure water availability when demand increases and partially decouples production and usage cycles.

Storage can also help secure the process. Depending on how the infrastructure operates, having a reserve volume available can reduce the impact of a temporary interruption in water production or a change in demand.

The Tank Is an Integral Part of the Installation

A tank should not be viewed simply as a piece of equipment installed downstream of the reverse osmosis unit. Its sizing and configuration must be consistent with the treatment unit's flow rate, process requirements, distribution equipment and operating conditions.

The treatment process may combine several stages of filtration, including ultrafiltration or specific filters depending on the required water quality. A reverse osmosis membrane can then remove a large proportion of dissolved salts and many contaminants. Upstream, activated carbon may be used in some configurations, particularly to treat chlorine. However, these purification systems do not replace the role of the storage tank: the tank comes into play after the treated water has been produced.

Treatment solutions available on the market may also combine reverse osmosis, ultrafiltration, filtration and remineralisation systems depending on the application. Storage must therefore be defined according to the actual quality of the water produced, rather than according to a theoretical treatment model.

What criteria should you consider when choosing a reverse osmosis water storage solution?

The Quality of the Water Produced by Reverse Osmosis

Water quality determines which materials and sealing systems can be used. Very low-mineral-content water can be aggressive towards certain materials. The tank material must therefore be selected according to the water's purity, its intended use and the storage conditions.

It is also important to distinguish between reverse osmosis water intended for an industrial process and drinking water. Drinking-water treatment may involve different filtration stages to reduce certain contaminants, including pesticides, but storage requirements remain linked to the final use.

Volume and Consumption Profile

The required volume should be determined using actual site data: production flow rate, average consumption, demand peaks, operating cycles and the required level of autonomy.

An oversized tank is not necessarily the best solution. Storage time, available space, network pressure and operating conditions must also be taken into account.

Industrial Site Constraints

The tank installation may be subject to various constraints: available space, site access, climatic conditions, ground conditions or specific requirements related to the industrial environment.

These parameters should be incorporated into the design from the study stage onwards to avoid costly adaptations during installation. Connections, the distribution network, water flow and the equipment required should also be defined at this stage.

Which material should be used to store this Type of water?

There is no single material that is universally suitable for every reverse osmosis system. The choice depends in particular on the characteristics of the water, the required level of purity, the storage duration and the process constraints.

Steel with a Suitable Coating

Steel tanks with an internal protection system can be used when the coating and sealing system are suitable for the stored liquid. APRO Industrie offers, in particular, galvanized steel tanks with a sealing membrane, as well as epoxy-coated steel solutions.

Stainless Steel

Stainless steel may be selected for applications requiring specific corrosion-resistance characteristics or compatibility with the stored liquid. The grade should be determined according to the project's actual requirements.

Glass-Fused Steel or Other Solutions

Glass-fused steel is another solution offered by APRO Industrie for storing reverse osmosis and demineralized water. The objective is to select a solution that provides an appropriate level of compatibility with the stored water, durability and maintenance requirements for the site.

Why choose a Bolted Steel Tank?

Bolted steel tanks are made from panels manufactured in a workshop and then assembled on site. This design allows the components to be transported as a kit and the tank to be installed without on-site welding.

A Modular Design Suited to Industrial Projects

The bolted design simplifies transportation and on-site installation. APRO tanks can be dismantled and relocated, while their modular design allows certain adaptations depending on the project.

This approach can be particularly useful when site access, logistical constraints or the industrial environment make welding operations difficult.

Installation Integrated into the Project Schedule

The installation of a tank can be organized around the overall project schedule. The actual duration naturally depends on the tank volume, its configuration and site conditions.

How should a tank be sized after reverse osmosis?

Sizing should be based on how the system actually operates. Several parameters need to be assessed:

production flow rate of the reverse osmosis unit
average and maximum process consumption
production and usage cycles
required buffer volume
required autonomy
storage time
installation constraints
equipment and accessories required for operation

This analysis makes it possible to determine a capacity suited to the site's actual operation rather than selecting a standard tank volume.

From 5 m³ to 10,000 m³ Depending on the Project

APRO Industrie designs storage solutions ranging from 5 m³ to 10,000 m³, depending on the application and project characteristics. This range covers very different requirements, from buffer volumes to large capacities intended for industrial infrastructure.

What industrial applications use reverse osmosis water?

Water produced by reverse osmosis can be used in a variety of industrial sectors. It may be used, in particular, to produce processed water, in certain cooling circuits, to prepare boiler feedwater or during various manufacturing and treatment stages.

Storage requirements therefore vary according to the application. In sensitive sectors, the design must take into account the water's purity, applicable conditions and the specific constraints of the process.

Why choose APRO Industrie for your Storage Solution?

Since 1987, APRO Industrie has designed, manufactured, installed and maintained bolted steel tanks for storing various liquids. Its solutions for reverse osmosis and demineralized water are available in galvanized steel, epoxy-coated steel, glass-fused steel or stainless steel, with suitable sealing systems.

Every project has its own constraints. APRO Industrie can incorporate the tank volume, water characteristics, climatic conditions, tank location, connections and operating requirements into the design study.

Support covers several stages:

study → design → manufacture → delivery → installation → maintenance

Maintenance depends on the material, sealing system, tank configuration and operating conditions. Inspections can be used to check the overall condition of the structure, equipment, joints and sealing components.

Reverse osmosis: do not confuse treatment with storage

The different water treatment systems each have a specific function. One or more filters may be used before reverse osmosis; a membrane performs the separation specific to the process; and additional stages may complete the purification process depending on the required water quality.

Replacing filter elements, replacing consumables and carrying out maintenance operations therefore concern the treatment system, while the storage tank must preserve the quality of the water once it has been produced. These operations can be planned independently, particularly when a subscription or maintenance contract is provided for a domestic or industrial treatment system.

Information available on the web about filtration models and accessories should therefore be distinguished from the actual characteristics of the tank to be installed. A compact piece of equipment designed to produce filtered water is subject to different requirements from an industrial tank holding several thousand cubic metres.

FAQ: Reverse Osmosis and Water Storage

Is water recirculation in the tank necessary?

It depends on the required water quality, storage time and industrial process. For certain applications, recirculation can be implemented to limit areas of stagnation. The configuration must then include the necessary pumps, pipework, connections and circulation equipment.

How long can reverse osmosis water be stored?

There is no universal storage duration. It depends in particular on the water's initial condition, temperature, the level of protection provided by the tank, operating conditions and final use. The longer the residence time, the more carefully the storage design needs to be studied to preserve water quality.

What equipment should be included?

Depending on the project, a tank may include connections, an overflow, a drain, a vent, maintenance access, a level indicator and connections to the distribution network. Accessories are defined according to the tank capacity, installation location and characteristics of the stored liquid.

Can a tank be integrated into an existing installation?

Yes, provided that the site constraints and the characteristics of the upstream and downstream networks are studied. The project can take into account available dimensions, access, connections, production flow rate and process requirements.

What about drinking water?

A tank intended for drinking water must meet specific requirements. Drinking-water storage, reverse osmosis water storage and process-water storage should not be treated as interchangeable: the material, sealing, equipment and applicable standards depend on the intended use.