What is Water Tank Storage?

What is Water Tank Storage?

Water tank storage is a storage solution for water, used for domestic, agricultural, and industrial purposes. Water storage tanks come in a range of materials, shapes, and sizes, depending on the intended use of the tank.

The main role of a water storage tank is to store water before it is used for drinking, washing, cleaning, and so on - but many storage tanks are more complex than they seem.


Types of Water Storage Tanks

There are several common types of water storage tanks used in the home, explained in detail below:

Well Pressure Tanks

Well pressure tanks are installed in properties that get their water from a well supply. A well pressure tank maintains water pressure and prevents the well pump from cycling on and off throughout the day, lengthening its lifespan.

How does a well pressure tank work? The tank fills contains a steady supply of water that is sent to appliances before the well pump needs to kick into action. This means that the well pump isn’t required to switch on and off to provide small amounts of water - such as water to wash your hands with.

Well pressure tanks compress air when water fills the storage tank. When water is needed, pressurized water is released into the plumbing system.

Thermal Expansion Tanks

Thermal expansion tanks are used to increase the capacity of tank-style hot water heaters. These water heaters expand when they heat water up (known as thermal expansion). The expansion and contraction of the tank put strain on the walls of the tank, increasing the likelihood of bursting.

What is Water Tank Storage?

A thermal expansion tank prevents the risk of expensive damage to a water heater by connecting to the water tank and providing additional space for water to go during heating. This prevents water from pushing against the sides of the tank heater, controlling pressure build-ups.

Reverse Osmosis Tanks

Reverse osmosis storage tanks are small-scale versions of water pressure tanks. The role of a reverse osmosis tank is to provide pressurized, purified water whenever it is needed. The reverse osmosis process takes several minutes, and without a tank, there would be a delay in water production. Storage tanks allow instant access to RO water and require the RO system to only operate when the tank needs to be refilled.

Rolled steel and butyl are common external and internal materials for reverse osmosis tanks. Most RO tanks are designed to fit underneath a kitchen sink, as a final stage to an under-sink reverse osmosis system. To avoid contaminating water with potential bacteria buildup inside the tank, a final filter stage is usually featured at the point at which water leaves the tank.


How Does a Water Storage Tank Work?

The exact way that a water storage tank works depends on the tank’s purpose.

In most cases, water storage tanks are used to provide instant access to water. For instance, well pressure tanks provide water immediately for quick jobs like filling a glass of water, preventing the need to wait until the well pump has kicked in and brought water up from the well.

The same goes for reverse osmosis tanks: the tank fills with purified water when the water isn’t needed. This means that when water is needed, it can be accessed from the tank instantly.

Pressure Tanks Vs Atmospheric Tanks

There are two types of tanks used for water storage: pressure tanks and atmospheric tanks.

Pressure Tanks

Pressure tanks, as the name suggests, produce water pressure using compressed air. An air bladder or chamber is used inside a pressure tank. The weight of the water filling the tank compresses the air, resulting in a building of pressure inside the tank.

Once a certain pressure is achieved, the tank stops admitting water. When water is needed, pressurized water from the tank is propelled through the plumbing system and into the appliance. Because water has left the tank, the air will expand and the pressure will decrease inside the tank. The tank’s low pressure will prompt the well pump or reverse osmosis system to produce more water to refill the tank.

Atmospheric Tanks

Atmospheric tanks hold water at ambient pressure - or the pre-existing water pressure in the tank’s location. A water booster pump is needed to draw water out of this type of storage tank and send it through the plumbing system.

Large-scale or outdoor applications are more likely than indoor applications to use atmospheric tanks. For instance, UV-stablilized atmospheric tanks are used for agricultural purposes, water distribution, rainwater collection, and transporting wastewater. Atmospheric tanks can hold thousands of gallons of water and tend to be more weather resistant than pressurized tanks.

Uses of Water Storage Tanks

Water storage tanks have a range of uses in commercial, industrial and residential applications. In the majority of situations, if water needs to be stored, a water storage tank can be used.

Some of the common uses of water storage tanks are as follows:

The tank’s size, materials, and specifications will be tailored to its intended use and water demands.

Sizing a Water Storage Tank

Water usage and purpose of use are both considered when determining the appropriate size of a water storage tank. There must be enough water to meet demand at all times, and sizing too small may result in a temporary water shortage as the tank refills with water.

Specific information, such as flow rates, pressure switch setting, and tank drawdown capacity are needed when sizing a well water storage tank. Manufacturers can support homeowners in deciding on the right-sized tank for an at-home water storage solution.


Water storage tanks are used to store water and provide faster access to a water supply. Atmospheric and pressurized water storage tanks are available, and atmospheric tanks are more commonly used for outdoor, large-scale applications, while pressurized tanks are used for indoor applications. Water storage tanks have a variety of uses across a number of industries.