Moving large volumes of liquid safely from one place to another is just as important as storing it correctly. If your team is exploring efficient ways to transport liquids across long distances, it is worth reading about the top ISO tank container companies for efficient delivery which breaks down the best options for transporting liquids in certified containers globally. Once transport is covered, the next big question is always storage. That is exactly what this guide addresses: how above ground water storage tanks work, what makes them a smart investment, and where they are used most.
What Are Above Ground Water Storage Tanks?
A Clear, Simple Definition
An above ground water storage tank is exactly what the name says: a tank that sits on the surface of the ground rather than being buried underground. These tanks store large amounts of water or other liquids for later use.
They come in many shapes, sizes, and materials. Industries use them to hold drinking water, fire suppression water, process water, chemicals, and more. They are a visible, accessible, and cost-effective way to manage large liquid volumes.
How They Differ From Underground Tanks
Underground tanks are hidden but harder to inspect and maintain. An above ground storage tank is easier to inspect visually, quicker to repair, and far less expensive to install. There is no excavation needed.
The Role of API 650 in Storage Tank Standards
What Is API 650?
API 650 is a design and construction standard published by the American Petroleum Institute. It sets the rules for how large, welded, flat-bottom API 650 storage tanks must be designed, fabricated, and tested.
Although the standard originated in the oil industry, it is now widely used for water storage tanks, chemical storage, and any large-volume above ground application. Buyers and project owners often require API storage tanks because the standard guarantees structural integrity and safe operation.
Why API 650 Compliance Matters
A tank built to API 650 standards goes through strict engineering calculations for wind load, seismic load, internal pressure, and shell thickness. Every weld is inspected and tested. The tank bottom is designed to handle settlement and soil conditions.
This level of rigor means API 650 storage tanks have a long service life, often 30 to 50 years with predictable maintenance needs. For industrial water storage, that reliability is priceless.
Choosing the Right Material for Your Tank
Carbon Steel: The Workhorse Option
Carbon steel is the most widely used material for large above ground water storage tanks. It is strong, weldable, and relatively affordable. Carbon steel tanks can be coated internally with epoxy or other linings to resist corrosion from water and chemicals.
For fire water storage, potable water reserves, and industrial process water, a properly coated carbon steel tank delivers excellent long-term value.
Stainless Steel: The Corrosion-Resistant Choice
When the stored liquid is corrosive, chemically active, or must meet food-grade or pharmaceutical purity standards, a stainless steel water storage tank is the right solution. Stainless steel resists rust, bacteria buildup, and chemical attack without needing internal coatings..
Fiberglass and Polyethylene: Lightweight Alternatives
For smaller above ground storage tanks typically under 50,000 gallons fiberglass reinforced plastic (FRP) and high-density polyethylene (HDPE) are popular choices. These materials are naturally corrosion-resistant, lightweight, and easy to install.
They work well for chemical storage, rainwater harvesting, and agricultural water supply. However, they are not suitable for very large volumes or high-temperature applications.
Material Comparison: Above Ground Storage Tank Options
|
Material |
Best For | Corrosion Resistance | Typical Capacity |
Standard |
|
Carbon Steel |
Fire water, process water, oil | Medium (needs coating) | 10,000 – 10M+ gal |
API 650 |
|
Stainless Steel |
Food, pharma, drinking water | High (no coating needed) | 500 – 500,000 gal |
ASME / API |
|
Fiberglass (FRP) |
Chemicals, agriculture | Very High | 500 – 100,000 gal |
ASTM D3299 |
|
HDPE / Polyethylene |
Rainwater, irrigation | Very High | 50 – 20,000 gal |
NSF 61 |
|
Hastelloy / Alloy |
Aggressive acids, high-temp | Exceptional | Custom |
ASME / API |
Key Benefits of Above Ground Water Storage Tanks
Easy Access for Inspection and Maintenance
One of the biggest advantages of an above ground water storage tank is how easy it is to inspect. Workers can walk around the tank and visually check for leaks, corrosion, or structural issues without any digging. Internal inspections are also straightforward through access hatches.
Lower Installation Cost Than Underground Tanks
Installing an above ground storage tank does not require excavation, soil removal, or underground waterproofing. This saves a lot of time and money. A prepared concrete or gravel pad foundation is usually all that is needed.
For large industrial facilities or remote sites where heavy excavation is difficult, above ground tanks are the most practical and affordable storage solution available.
Scalable Capacity for Any Project
Above ground storage tanks can be sized to almost any volume requirement. A small water treatment plant might use a 5,000-gallon tank. A large petrochemical facility might install several million-gallon tanks on the same site.
Where Above Ground Water Storage Tanks Are Used
Municipal and Drinking Water Systems
City water departments rely on large above ground water storage tanks to maintain pressure and supply across distribution networks. These tanks are often called elevated storage tanks or standpipes.
Oil, Gas, and Petrochemical Facilities
The oil and gas sector is one of the largest users of above ground storage tanks. API 650 storage tanks store crude oil, refined petroleum products, produced water, and chemical additives at well sites, refineries, and terminals.
Industrial Water Treatment Plants
Water treatment plants use above ground tanks to hold raw water, treated water, and process chemicals at every stage of purification. Proper tank sizing ensures a steady supply to filtration and chemical dosing systems.
Agriculture and Irrigation Systems
Farms and irrigation networks depend on above ground storage tanks to collect rainwater, store well water, and hold water for drip irrigation systems. Polyethylene tanks are popular here because they are affordable and lightweight. In drought-prone regions, on-site water storage is not just convenient, it is essential for keeping crops alive during dry spells.
Industry Applications at a Glance
|
Industry |
Tank Type Used | Primary Purpose | Typical Standard |
|
Municipal Water |
Carbon steel, elevated |
Pressure maintenance, emergency reserve |
AWWA D100 |
|
Oil & Gas |
Carbon steel, large-volume |
Crude, refined products, produced water |
API 650 |
|
Chemical Plants |
Stainless steel / FRP | Chemical storage, process water |
ASME / API |
|
Food & Pharma |
Stainless steel 316L | Ingredient water, CIP rinse water |
NSF / FDA |
| Fire Protection | Carbon steel or FRP |
Emergency fire suppression supply |
NFPA 22 |
|
Agriculture |
HDPE / Polyethylene |
Irrigation, rainwater harvesting |
NSF 61 |
How Air Cooled Heat Exchangers Support Storage Tank Systems
Cooling Hot Process Fluids Before Storage
In many industrial plants, liquids are processed at high temperatures before they are stored in an above ground storage tank. If a hot fluid enters a storage tank directly, it can damage the tank lining, accelerate corrosion, or cause safety issues. This is where an air cooled heat exchanger plays a critical role.
Why Air Cooled Heat Exchangers Are Ideal for Remote Tank Sites
Many large storage tank farms are located in remote areas far from water supplies. Air cooled heat exchangers also known as fin-fan coolers or heat exchanger air cooled units work perfectly in these locations. They only need electricity to run the fans and ambient air to cool the process stream.
Frequently Asked Questions
What is an above ground water storage tank used for?
Above ground water storage tanks are used to hold large volumes of water or other liquids at ground level. Common uses include drinking water reserves, fire suppression water, industrial process water, chemical storage, and agricultural irrigation supply.
What does API 650 mean for a storage tank?
API 650 is a construction standard from the American Petroleum Institute. It sets rules for how large, welded, flat-bottom above ground storage tanks must be designed, built, and tested. Tanks meeting API 650 are engineered for safety, long service life, and structural reliability under wind, seismic, and liquid load conditions.
Why choose a stainless steel water storage tank?
A stainless steel water storage tank is the best choice when corrosion resistance, hygiene, or chemical compatibility is important. It does not need internal coatings and resists bacteria growth. It is widely used in food and beverage plants, pharmaceutical facilities, and potable water systems.
How long do above ground storage tanks last?
A well-built above ground storage tank can last 30 to 50 years when properly maintained. API 650 carbon steel tanks with quality coatings and regular inspection programs often exceed this range. Stainless steel tanks can last even longer with minimal maintenance.
Conclusion
Above ground water storage tanks are one of the most practical, cost-effective, and reliable storage solutions in industry today. From municipal water supply to oil and gas terminals, fire protection systems, and chemical plants, these tanks handle the world’s most important liquid management needs every day.
Choosing the right tank means picking the correct material, following the right standard such as API 650 and pairing the tank with the right support equipment, including air cooled heat exchangers where process cooling is required. Chemted LLC supplies certified API storage tanks and stainless steel tanks built to the highest quality and compliance standards. Explore their full product range to find the right solution for your next project.
