Water storage does not always require a permanent steel or rigid tank. Some projects need storage that can be transported, deployed quickly, or removed after use.
Flexible storage tanks can provide an alternative for these applications. Two terms commonly associated with flexible storage are bladder tanks and pillow tanks.
These tanks use flexible materials rather than rigid steel or plastic walls. They can provide temporary or relocatable storage across commercial, industrial, agricultural, and emergency applications.
However, flexible tanks also have specific installation, handling, and site requirements. Understanding their construction and limitations helps determine where they can provide an appropriate storage solution.
This guide explains flexible storage tanks, including bladder tanks, pillow tanks, their applications, and key selection considerations.
What are Flexible Storage Tanks?
Flexible storage tanks are collapsible containers designed to hold liquids without permanent rigid walls. Their flexible construction allows the tank to change shape as it fills or empties.
When empty, many designs can be folded or rolled for transportation and storage. When filled, the stored liquid gives the tank its operational shape.
Flexible tanks are manufactured using engineered fabrics and liquid-resistant materials. Material selection depends on the liquid, capacity, environmental conditions, and intended application.
Flexible tanks may be used for:
- Water storage
- Emergency water supplies
- Agricultural operations
- Remote worksites
- Construction projects
- Temporary facilities
- Industrial applications
- Disaster response
- Firefighting support
- Site water management
Their main advantage is flexibility in both deployment and storage. However, they are not direct replacements for rigid tanks in every application.
What is a Bladder Tank?
A bladder tank is a flexible container designed to hold liquid within a sealed membrane. The term describes the tank’s flexible, expandable construction. Unlike rigid tanks, bladder tanks do not require permanent structural walls to maintain their empty shape.
The tank expands as liquid enters. It contracts as the stored liquid is discharged. Bladder tanks can be manufactured in different shapes and capacities.
They may be positioned on prepared ground or installed within another supporting structure. Some bladder systems are also designed for specialised industrial applications.
The exact configuration depends on the intended use. Explore our bladder tanks for flexible water storage across temporary, remote, commercial, and industrial applications.
What is a Pillow Tank?
A pillow tank is a common type of flexible bladder tank. Its name comes from its characteristic shape when filled. An empty pillow tank lies relatively flat.
As liquid enters, the centre rises while the tank expands across its footprint. The resulting form resembles a large pillow. Pillow tanks are generally enclosed flexible containers.
They usually include fittings for filling, discharge, venting, or other operational requirements. Their low-profile shape can make them useful where vertical clearance is limited.
They can also be transported more easily than many rigid tanks when empty.
Are Bladder Tanks and Pillow Tanks the Same?
The terms are often used interchangeably. However, “bladder tank” can describe a broader category of flexible liquid storage systems. A pillow tank generally refers to a specific low-profile bladder design.
Therefore, most pillow tanks can be considered bladder tanks. Not every bladder system necessarily uses the traditional pillow-shaped configuration. Terminology can also vary between manufacturers and industries.
The tank specification is more important than the terminology alone. Users should confirm the tank’s construction, material, capacity, fittings, and intended liquid.
How do Flexible Storage Tanks Work?
Flexible tanks rely on the stored liquid to develop their operating shape. The empty tank is placed on a suitable prepared surface. Connections are then made to the required inlet and outlet fittings.
As liquid enters, the tank gradually expands. The tank continues filling until it reaches its specified operating capacity. Liquid is later removed through the appropriate discharge connection.
As the liquid level falls, the flexible structure contracts. Once empty, many tanks can be prepared for relocation or storage.
This operating principle removes the need for permanent rigid tank walls. However, correct positioning and filling procedures remain important.
What Materials are Used for Flexible Tanks?
Flexible tanks require materials capable of containing the intended liquid. The exact material varies between products and applications. Many flexible tanks use reinforced technical fabrics.
These materials may combine a structural textile with protective polymer coatings. The structural fabric provides strength.
The coating provides liquid containment and environmental protection.
Depending on the application, materials may need resistance to:
- Water
- UV exposure
- Abrasion
- Temperature changes
- Weather
- Specific chemicals
- Repeated folding
- Mechanical stress
Material compatibility is especially important for industrial liquid storage. A membrane suitable for water may not suit fuels or aggressive chemicals.
Tank materials should always match the intended stored liquid.
What can Flexible Storage Tanks Hold?
Water is one of the most common liquids stored in flexible tanks. However, the exact storage capability depends on the tank material and certification.
Possible applications can include:
- Potable water
- Rainwater
- Process water
- Agricultural water
- Emergency water
- Firefighting water
- Wastewater
- Some industrial liquids
Not every flexible tank can store every liquid. Potable water applications require suitable water-contact materials.
Industrial liquids require appropriate chemical compatibility. Wastewater can create different requirements again.
The liquid should therefore be identified before selecting the tank material.
Flexible Tanks for Potable Water
Flexible tanks can be manufactured for potable water storage. However, the membrane must be suitable for drinking-water contact. Fittings and other components should also suit potable applications.
The stored water must remain protected from contamination during operation. Site preparation is also important. The tank should be positioned away from potential contamination sources.
Connections should remain clean during installation and use.
Potable water storage may be particularly useful for:
- Remote camps
- Temporary facilities
- Emergency response
- Construction sites
- Events
- Isolated communities
Applicable drinking-water requirements should be confirmed for each project.
Flexible Tanks for Rainwater Storage
Flexible tanks can also store collected rainwater. This may be useful where permanent tank installation is unnecessary. A flexible tank can provide additional storage during particular seasons or projects.
Rainwater quality still requires appropriate management. Roof debris and sediment should be controlled before water enters the tank. Screens and filtration may form part of the collection system.
The intended use of the rainwater also matters. Water used for irrigation has different requirements from drinking water.
A suitable tank material should be selected for the intended application.
Flexible Tanks for Emergency Water Storage
Emergency response is a strong application for flexible tanks. Water storage may need to be established quickly after an emergency. Transporting large empty rigid tanks can be difficult.
A collapsed flexible tank occupies considerably less transport space. This can simplify logistics when equipment must reach remote locations.
Once delivered, the tank can be deployed on a prepared site.
Emergency applications may include:
- Natural disasters
- Temporary water supply interruptions
- Remote response operations
- Emergency camps
- Infrastructure failures
- Fire response support
The required capacity and deployment conditions should be planned before an emergency occurs.
Flexible Tanks for Firefighting Water
Flexible tanks can provide temporary water storage for some firefighting operations. Their portability can be useful in remote or temporary locations. Water can be positioned closer to areas where it may be required.
However, temporary flexible storage differs from permanent fire water infrastructure. Permanent fire protection systems can have specific engineering and compliance requirements. A flexible tank should not automatically replace a compliant permanent fire water tank.
Its role should be determined by the fire protection strategy. Access, fittings, flow requirements, and capacity also need consideration.
Agricultural Uses for Bladder and Pillow Tanks
Agricultural operations often require water in changing locations. This can make flexible storage useful. A bladder tank can provide temporary storage near crops, livestock, or remote work areas.
Possible agricultural applications include:
- Irrigation water
- Livestock water
- Rainwater storage
- Remote field operations
- Temporary water transfer
- Seasonal water requirements
Portability can be particularly useful across large properties. An empty tank can potentially be relocated when operational requirements change.
However, the new site still requires proper preparation. Explore pillow tanks water storage solutions for temporary, portable, and space-efficient water storage applications.
Flexible Tanks on Construction Sites
Construction projects often have temporary water requirements. These requirements can change as the project develops. A permanent tank may not always be necessary.
Flexible tanks can provide temporary storage during specific construction stages.
Stored water may support:
- Dust suppression
- Equipment washing
- General site use
- Temporary facilities
- Water transfer
- Emergency requirements
The tank can potentially be removed when the project finishes. This reduces the need for permanent storage infrastructure.
However, construction sites can contain sharp debris and uneven ground. Surface preparation is therefore especially important.
Why is Site Preparation Important?
Flexible tanks make direct contact with the supporting surface. This makes ground preparation critical. Sharp stones, metal fragments, branches, and construction debris can damage the tank material.
The site should be smooth, stable, and appropriately level. The supporting surface should also accommodate the full tank footprint. Remember that water is extremely heavy.
One litre of water has a mass of approximately one kilogram. A large flexible tank can therefore place substantial loads on the ground. The site must safely support the filled tank.
Protective ground sheets may also be used where appropriate.
How Much Space does a Pillow Tank Need?
Pillow tanks generally require a larger horizontal footprint than rigid vertical tanks. The tank spreads outward as it fills. Its final dimensions depend on capacity and design.
Adequate clearance should remain around the tank. Connections must also remain accessible. The site should not restrict the tank’s normal expansion.
This makes available ground area an important selection factor. A narrow site may favour a vertical rigid tank instead.
A site with generous horizontal space may accommodate a pillow tank more easily. Tank dimensions should always be reviewed before installation.
What are the Advantages of Flexible Storage Tanks?
Flexible tanks can provide several practical advantages for suitable projects.
Compact Transport
An empty flexible tank occupies much less space than an equivalent rigid tank. This can simplify transportation to remote or temporary sites.
Rapid Deployment
Many flexible tanks can be positioned without constructing a complete rigid tank structure. Installation requirements still depend on capacity and site conditions.
Relocation
Some tanks can be drained and moved when storage requirements change. This can suit temporary or seasonal operations.
Low Profile
Pillow tanks generally have a relatively low filled height. This can help where vertical clearance is limited.
Temporary Storage
Flexible tanks can provide storage without committing to permanent infrastructure. This is useful for construction, emergency, and short-term projects.
Range of Capacities
Flexible tanks are available across different storage capacities. The appropriate capacity depends on the application and available footprint.
What are the Limitations of Flexible Tanks?
Flexible tanks also have limitations that should be considered before selection. Their membranes are exposed to physical damage if the installation area is unsuitable. Sharp objects can create puncture risks.
The tank also requires enough horizontal space to expand. This can be challenging on restricted sites.
Flexible tanks may also require protection from:
- Vehicles
- Machinery
- Animals
- Vandalism
- Sharp debris
- Excessive abrasion
- Unsuitable chemicals
Long-term requirements may favour permanent tank systems. The correct solution depends on how the storage will actually be used.
Flexible Tanks vs Rigid Water Tanks
Flexible and rigid tanks solve different storage problems. Rigid tanks maintain their shape whether empty or full. Flexible tanks change shape according to their contents.
Rigid tanks can be constructed from materials such as:
- Galvanised steel
- Stainless steel
- Concrete
- Polyethylene
- Fibreglass
They are commonly selected for permanent storage infrastructure. Flexible tanks can provide advantages where portability and temporary deployment are priorities.
They can also reduce transport volume when empty. However, they usually require greater protection from physical damage.
The choice should reflect project duration, location, capacity, and operational requirements.
Flexible Tanks vs Steel Tanks
Steel tanks are commonly used for permanent and large-scale water storage. Their rigid structure can support long-term installations. They can also be engineered for substantial capacities and specific site requirements.
Flexible tanks serve a different purpose. They can be valuable where storage must be deployed quickly or moved later. The two systems should therefore not be viewed as direct competitors in every situation.
A permanent facility may benefit from a steel tank. A temporary remote project may benefit from a flexible bladder tank.
Some projects can even use both systems for different purposes.
Do Flexible Tanks Require a Foundation?
Flexible tanks do not necessarily require the same foundation design as large rigid tanks. However, this does not mean they can be placed on any surface. The supporting area must safely carry the full water load.
It should also remain stable during operation. Uneven settlement can create undesirable stress on the tank. Sharp objects can damage the membrane.
Surface preparation requirements depend on tank size, design, and site conditions. Larger tanks require particularly careful planning.
Manufacturer installation requirements should always be followed.
Can Flexible Tanks be Used Outdoors?
Many flexible storage tanks are designed for outdoor use.However, outdoor conditions can be demanding. UV radiation can affect some materials over time.
Temperature changes can also influence tank materials and stored liquids. Wind, rainfall, animals, and surrounding activities create additional considerations.
Outdoor installations should account for:
- UV exposure
- Temperature range
- Drainage
- Ground conditions
- Vehicle movements
- Wildlife
- Site security
The tank material should suit the expected environmental exposure.
What Fittings do Flexible Tanks Need?
Flexible tanks require appropriate fittings for filling and discharge. The exact configuration depends on the application.
Common components can include:
- Inlet fittings
- Outlet fittings
- Valves
- Hoses
- Vents
- Caps
- Connections
- Pressure relief components
Fitting locations can influence installation and operation. Connections should remain accessible when the tank is full.
Hoses should not place unnecessary loads on the tank fittings. The required flow rate should also be considered.
Large-volume water transfer may require larger connections.
Can a Pillow Tank be Completely Filled?
Flexible tanks should be filled according to their specified operating capacity. Overfilling can create excessive stress on the membrane and fittings. The tank needs enough flexibility to assume its designed filled shape.
Operators should follow the specified capacity and filling procedures. The surrounding area should also remain clear during filling. Tank shape should be observed during initial deployment.
Any unusual movement or deformation should be investigated. Correct filling is an important part of safe operation.
How are Flexible Tanks Emptied?
Liquid is generally removed through a dedicated outlet connection. Gravity may be sufficient for some applications. Other systems may use pumps.
The required discharge method depends on site conditions and operational needs. As liquid leaves, the tank gradually collapses. Some residual liquid may remain depending on the design and site level.
Complete drainage may be important before relocation. The tank should be handled according to manufacturer instructions after emptying.
Can Flexible Tanks be Reused?
Many flexible tanks are designed for repeated deployment. However, reuse depends on their condition and intended application.
The tank should be inspected before redeployment.
Operators should look for:
- Cuts
- Abrasion
- Punctures
- Damaged fittings
- Seam damage
- Material deterioration
- Contamination
Cleaning requirements depend on the previously stored liquid. Potable applications may require particularly careful hygiene controls.
A damaged tank should not be reused without appropriate assessment or repair.
How Should Flexible Tanks be Stored when Empty?
Correct storage helps protect a flexible tank between deployments. The tank should generally be clean and sufficiently dry before long-term storage. Residual water can create hygiene or material issues.
The tank should be folded or rolled according to its design requirements. Storage areas should protect the material from unnecessary damage. Avoid placing heavy or sharp objects on the stored tank.
Exposure to chemicals should also be prevented. The tank should remain identifiable for future inspection and deployment.
How do You Choose a Flexible Storage Tank?
Tank selection starts with understanding the application. Capacity alone is not enough. Several factors should be considered.
These include:
- Stored liquid
- Required capacity
- Available footprint
- Storage duration
- Site conditions
- Water quality requirements
- Operating temperature
- Required fittings
- Filling method
- Discharge method
- Transport requirements
- Expected relocation
- Environmental exposure
Material compatibility should receive particular attention. The tank must be designed for the liquid it will contain.
Bladder Tank or Pillow Tank: which Should You Choose?
The terminology can sometimes make tank selection seem more complicated than necessary. A pillow tank is generally a form of flexible bladder tank. Therefore, the decision should focus on the actual tank specification.
Start with the liquid being stored. Then determine the required capacity and available installation area. Consider whether the tank will remain in place or move between sites.
Review environmental conditions and potential physical hazards. Finally, confirm the membrane, fittings, and design suit the application.
These factors are more useful than choosing based on product terminology alone.
When does Flexible Water Storage Make Sense?
Flexible storage is particularly useful when permanent infrastructure is unnecessary or impractical. It can support temporary, mobile, seasonal, and emergency requirements.
A flexible tank may make sense when:
- Storage is required temporarily
- Equipment must reach a remote site
- Empty transport space is limited
- The tank may need relocation
- Vertical clearance is restricted
- Rapid deployment is important
- Permanent construction is unnecessary
Rigid tanks remain more appropriate for many permanent installations. The project requirements should determine which approach provides the better fit.
Final Thoughts
Flexible storage tanks provide an adaptable approach to temporary and relocatable liquid storage. Bladder tanks use flexible membranes that expand as they are filled. Pillow tanks are a common bladder configuration with a distinctive low-profile shape.
These systems can support water storage across construction, agriculture, emergency response, and remote operations. Their collapsible design can simplify transport and deployment.
However, flexible tanks require suitable ground preparation and protection from physical damage. The membrane must also be compatible with the stored liquid. Capacity, site area, fittings, temperature, and storage duration should all be considered.
Flexible tanks are not universal replacements for permanent rigid tanks. Instead, they provide another storage option for projects where mobility and adaptability are important.
