Our Tanks


To better meet the needs of our customers, Superior Tank offers a full range of bolted and welded steel storage tanks. Our storage tanks feature an array of different finishes, coatings and capacities that are designed per site specifications, codes and industry standards. All of our storage tanks are equally suited for various applications such as the storage of potable water, wastewater, water for fire protection, crude oil, irrigation water and dry bulk material. With over 34 years of knowledge and experience as a Licensed General Contractor, building both bolted and welded storage tanks, we can help you decide which design is most appropriate for your project, considering time, budget constraints and aesthetics.

When time is critical or site access is limited, our precision manufactured bolted steel tanks are perfect. Designed and manufactured in our State-of-the-Art facility, our bolted tanks arrive at your jobsite ready to be assembled. Alternatively, we fabricate, build and install welded steel tanks throughout California, Arizona and Nevada. Our welded tanks are constructed of large steel plates joined together on the jobsite by our certified welders.

Regardless of which type you choose, you can be sure your storage tank will be “Simply Superior!”


When new or replacement tank parts are needed, Superior Tank can custom design and fabricate any part to fit the needs of your tank and project. We offer a variety of tank accessories including roof vents, manways, liquid level indicators as well as OSHA-approved access hatches and interior/exterior ladders. When replacement structural components are required, we can fabricate roof rafters, storage tank roof decks and bottoms in order to accommodate your changing needs.


ANAB Accredited
ISO 9001




API Spec Q1
NSF Certified

C0349754 & C0349755

FM Approved



With decades of experience in working with international customers, we have the tools necessary to ship your bolted tank directly to the jobsite. We offer variety of export services, such as our “Tank in a Box” program, which allows for our bolted steel tanks, along with hardware and accessories, to be easily shipped directly to any port in the world via ocean shipping container. Tools required for installation can be purchased and shipped with the tank. Our team of export specialists can provide you with all required documentation needed for a seamless importation. If needed, Superior Tank can also provide an experienced Supervisor to oversee the installation of your tank. Here’s a map exemplifying just how global of a storage tank provider we truly are:


As a family-owned and operated business, we understand the importance of building trust with our customers to ensure confidence when purchasing a steel storage tank. Over the past 34 years, we have garnered an abundance of knowledge and experience concerning the engineering, manufacturing, installing and servicing of bolted and welded steel storage tanks. With the backing of our reputable standing in the industry and mastery of steel storage tanks, we offer the following answers to some common questions to better assist you in familiarizing yourself with our products:


Absolutely! Our full time Professional Engineer / Structural Engineer is responsible for ensuring each bolted steel tank we manufacture will meet or exceed relevant industry standards established by the American Water Works Association (AWWA) D103-09, National Fire Protection Association (NFPA), American Petroleum Institute (API) and FM Approvals.  Moreover, the epoxy powder coating we apply to our water storage tanks is NSF Certified and we also offer bolted steel tanks which are NSF 61/372 Certified for drinking water storage. This NSF certification differentiates our tanks from others as concrete tanks and the concrete floors used with some bolted tanks lack NSF certification due to the local sourcing and unknown composition of the concrete.

In addition to industry standards, our tanks meet or exceed local building codes including snow and wind loads as well as seismic requirements. In fact, our bolted steel storage tanks can be engineered and manufactured to withstand wind loads up to 250mph!  Using heavier gauge, high strength carbon steel and anchoring the tank directly to the concrete foundation, we significantly increase our tank’s resistance to the forces of nature.  When the proper thickness and strength steel panels are used, wind girders around the top perimeter of the tank are not even needed.  As an illustration of the strength of our tanks, several of our bolted steel tanks in Chile survived large earthquakes without damage.


Yes!  Thicker steel does not equal greater strength as the quality of the steel makes a big difference. Our bolted steel tanks are constructed of high quality carbon steel for higher strength. Welded tanks require thicker steel to resist the heat of welding but the steel used is a lower strength. Superior Tank manufactures tanks with shell thicknesses up to 5/16” depending on the project requirements.  AWWA D103-09 includes 4-to-1 safety factors to ensure bolted steel tanks withstand a variety of environmental stresses.  Besides exclusively using higher strength steel, Superior Tank also inspects all raw material to ensure source steel meets various quality standards such as edge quality, surface quality, silicone content, squaredness and flatness.  Material not meeting our established standards will be rejected.


Most Superior Tanks are complete structures and include a roof, walls and a bottom to form one solid structure with uncompromising rigidity. Many glass-fused to steel tanks do not include tank bottoms and use site poured concrete foundations as the tank floor.  Unfortunately, this can lead to leaks as the concrete foundation and the tank shell expand and contract at different rates.  Moreover, concrete is porous and moisture can invade the foundation and corrode the steel reinforcement. Another advantage of using an integrated steel tank bottom is the tank shell is bolted to the tank bottom every 2” compared to other methods in which the tank is only attached to the bottom/foundation every 4” or more.  The design standard for the connection between the tank shell and the tank floor/bottom does not exist and the American Society of Civil Engineering (ASCE) 7-16 Standard for Minimum Design Loads and Associated Criteria for Building and Other Structures published in August 2017, includes an exception to the AWWA D103. Section relating to bolted steel tanks, includes new requirements stating tanks with an embedded steel base setting ring not be used in areas where the tank would experience uplift forces due to seismic activity. However, when permitted by building code and specifically requested by the customer, STCI can also provide bolted steel tanks with embedded shell starter rings.

Another advantage of using a high strength carbon steel tank bottom is the elimination of issues associated with the use of dissimilar materials.  Commonly glass fused to steel tanks with an embedded started ring utilize a variety of materials and finishes; glass coated shells, aluminum domes and galvanized wind girders as well as concrete tank bottoms/floors.


Our bolted steel tanks are MANDATED by the AWWA D103-09 standard not to leak as there is a ZERO leakage allowance.  Our vacuum tester system was specifically designed to verify compliance with this requirement. Conversely, the AWWA standard for concrete tanks actually allows for leakage illustrating the high probability of leaks with concrete tanks. This leakage risk also exists with bolted steel tanks using concrete floors and embedded shell ring walls as the concrete is porous and cannot be sealed or coated.

To ensure our bolted tanks do not leak, we install preformed gaskets between the staves.  While other bolted steel tank companies use a putty mastic to try to seal their tank, we use precision punched gaskets. The mastic takes 7-10 days to cure versus our synthetic rubber gaskets which can be put into service immediately. Our gaskets are available in various materials specific to the application; EPDM for water storage and Buna-N or Viton for oil and other petro chemical applications. As the gaskets are comprised of durable synthetic rubber, they remain pliable for decades and will not crack or peel.  Also, the flexibility of the gasket ensures that if a Superior Tank should experience a leak, the bolts can easily be tightened correcting the problem.  Tank manufacturers using putty mastic will commonly recommend replacing the mastic every 10 years.  With our bolted steel tanks, we do not require the gaskets to be replaced as we have found our gaskets to have a much longer lifespan than mastic (they look better too!).


Definitely! Every square inch of our bolted steel tanks are factory powder coated to protect against corrosion.  All of our powder coated tanks are pre-finished in our 50,000 square foot State-of-the-Art factory and thus there is no need to apply coatings in the field. By applying the coating to the individual tank components before the tank is erected, we are able to seal hard to reach places such as the underside of the tank bottoms and the top of roof rafters. In critical areas such as panel edges and bolt holes, two layers of powder coating are applied for additional protection. To permanently chemically and physically bond the coating to the steel, the coating is heated in large ovens. We have found a powder coated finish will commonly at least as long if not longer compared to liquid coatings used on welded tanks.   Our powder coating is applied using highly automated processes under tightly controlled conditions resulting in a high quality and defect free coating. Conversely, with welded steel tanks, the steel is prepared and coating is applied in the field leading to highly viable levels of quality. Welded steel tanks are sandblasted by hand and therefore are reliant on the skill and training of the human operating the equipment. Weather conditions during the coating application can negatively impact the coating lifespan. If the humidity level is too high and the coating is not applied directly after sandblasting, flash rust can occur preventing the coating from achieving full adhesion strength. If breezy conditions exist, the steel surface is too hot or ambient temperature is too high, the coating will dry before contacting the steel or will cure too fast. In addition, the liquid coating formula can vary from project to project which will impact the coating longevity. The skill and training of the person applying the coating will also affect the coating. If the paint gun operator does not have enough training, is sleepy or not paying attending, defects in the coating can occur which may not be evident until several years after the tank has been placed into service. Factory powder coating is immune from these potential issues.

For maximum durability, several powder coating formulas are available to meet the application. For example, epoxy is best for continuous emersion and is used for tank interiors. Conversely, a polyester TGIC formula is used for tank exteriors due to its outstanding UV resistance. For storage of corrosive liquids such as crude oil and brine, Scotchkote by 3M is available for greater coating lifespan.  Also, to protect tank appurtenances against corrosion and premature failure, all nozzles, manways and hatches are powder coated using the same process. Our powder coated tanks also include a Silica- Zirconium (SiZr) seal which provides a second layer of protection against corrosion in the event the coating is damaged by a thrown rock or dropped tool. This unique liquid sealant is sprayed onto the prepared steel before the powder coating is applied.

Tests by an independent lab have proven the longevity and durability of our powder coating. Various performance criteria were measured such as resistance to abrasion, significant impact, corrosive salt spray, high humidity and temperature and our powder coating met or exceeded performance benchmarks. The SiZr seal minimizes coating repairs needed and eliminates the spread of corrosion if the coating is damaged. Our factory powder coating has been PROVEN to provide superior performance.


Certainly! Modern bolted steel tanks from reputable manufacturers incorporate numerous innovations which significantly increases the longevity of the tank.  The lifespan of a powder coated bolted steel tank can exceed 50 years when the storage tank is properly maintained.  Our powder coated bolted steel tanks require only periodic coating touchups and the overall powder coating can last 20-30 years.  This differs from welded steel tanks which require recoating every 5-20 years, depending on the thoroughness of the steel preparation, the quality of the coating and the skill of the painter who applied the coating.

In addition, when compared to glass fused to steel bolted tanks, STCI tanks provide greater longevity. Our synthetic rubber gaskets do not require periodic replacement and remain pliable for many years. Most glass fused to steel bolted tanks use mastic putty to seal the tank which requires replacement every 10-15 years. In addition, if a glass fused to steel bolted tanks is damaged by a thrown rock or dropped tool, the only way to patch the steel is to apply a glob of sealant over the damage. If the patch does not adhere to the glass surface properly, the entire panel must be replaced. Commonly, glass fused to steel bolted tanks are considered to be “run to fail” as they CAN’T be recoated or repaired; once the coating is compromised the entire panel must be replaced.  This differs significantly from being truly “maintenance free”.  By comparison, our powder coating can easily be repaired in the field using two part liquid epoxies and the repair area commonly matches the existing coating. Also, as the entire tank can be recoated, it is not necessary to replace the whole tank when the coating reaches the end of its lifespan. Our epoxy coated tanks can be kept in service for many decades with routine maintenance.


Absolutely not! Our powder coating is good for the environment as well as the longevity of your tank. Our powder coating is applied dry using an electrostatic current thereby eliminating solvents which can evaporate polluting the air. Furthermore, these solvents can continue to evaporate after the tank is put into service resulting in taste and water quality issues. Moreover, no air polluting particulates are released as excess powder coating is captured before it can escape into the environment.

Besides being good for the environment, our powder coating will save you money compared to other coatings with higher initial costs and shorter lifespan.


Yes! We manufacture over 200 different standard configurations of bolted tanks ranging from capacities 4,000 to 2,200,000 gallons with various heights and diameters.  Our in house engineering department designs each tank to the specific requirements of the project and we operate our own manufacturing facility allowing us to provide other custom sizes if needed.


Superior Tank bolted steel tanks are prefabricated in our State-of-the-Art production facility and therefore all that is required on the job site is to bolt the tank together.  Our precision manufacturing process uses automated machinery to set to exact specifications and our tank components fit well together therefore eliminating onsite rework and modifications. Hot work such as welding and grinding are eliminated from the field which reduces fire danger and removes the need for extra equipment on site such as respirators, face protection, barrier creams for exposed skin, additional ventilation and explosion-proof equipment. Also, ASME welders with current certification do not have to travel to the job site on a daily basis and the need to x-ray welds which is not required as it is with welded tanks.  Besides, we apply the final coating to the tank and components in the factory and therefore slow and costly operations such as sandblasting and painting are not required on site. This also eliminates the need to wait until weather conditions (temperature, relative humidity level, dew point, predicted weather during drying time, etc) are just right before applying the coating.  As our powder coating is cured almost immediately, the tank can be put into service right away as it is not necessary to wait until the solvent has evaporated and the paint has properly cured.  After three decades in the storage tank industry, we have discovered assembling the bolted steel tank on the job site is faster, easier, more accurate and provides a longer life span compared to completely fabricating a steel storage tank in the open elements.


Our bolted steel storage tanks are NOT the same as bolted tanks manufactured by other companies and designed to provide superior performance.  Akin to quality differences in automobiles, the quality of bolted steel tanks can vary considerably from one company to another. Differences can include the quality of raw materials, the precision of the manufacturing process and company experience.  Other bolted tank companies claim to provide the highest quality products; but STCI has testing results from an independent laboratory verifying the durably and longevity of our tanks and coating systems. Further, STCI is recertified annually to comply with strict API Q1 / ISO 9001 standards which positively confirms our tanks meet design standards and quality objectives.  Without this, customers are not sure if the tank they are buying meets the required design standards and quality expectations. At Superior Tank Co., Inc. we have testing results to support our name!