RainFlo Corrugated Steel Tank Systems

RainFlo Corrugated Steel Tank Systems
RainFlo Corrugated Steel Tank Systems
RainFlo Corrugated Steel Tank Systems
RainFlo high quality corrugated steel tank systems range from 600 to 500,000 gallons.
Stock 100
Call for price. Custom tanks ship in about 8 weeks.
Configuration Options:

RainFlo corrugated steel tanks are configured with a variety of options including fill and overflow flanges, lids and hatches, ladders and stairs, anchors and more. Descriptions and details of these options are provided throughout this page.

For custom configurations call us at 800-654-WATER (9283)


Quality Service and Quality Products with the Best Pricing in the Industry

As communities, businesses and industries become increasingly accountable to meet LEED and other environmental requirements that require safe, design-proven storage, RainFlo is on the forefront with innovative answers. When considering the options in customized systems for water storage, facility designers and owners look for a long-term, structurally strong, watertight and cost effective solution. That is exactly what the RainFlo corrugated tank system is.

RainFlo steel water storage tanks use the latest technology and materials utilizing a bolted steel outer shell with a heavy duty liner. These tanks can be assembled at the project site by trained installation professionals or sold as product only, including a very detailed and easy to follow instruction manual.

Our RainFlo line of field-assembled corrugated steel water tanks are designed to be an aesthetically pleasing and cost effective water storage solution. These versatile tanks have been installed in several different countries in all types of climatic regions, including those that experience dry conditions, snow, earth quake and hurricane activity.

Corrugated Steel Rainwater TankCedar Wrapped Corrugated Steel Water TankCorrugated Steel Rainwater Tanks with Palm TreesCorrugated Fire Suppression Tank

Our tanks are designed to meet National Fire Protection standards (NFPA-22) and NSF/ANSI.STD 61 for the potable water storage option. Our engineering team can provide certified tank and foundation design to meet specific applications and project requirements. The modular design of our water tank enables it to be packaged flat and allows for easy transportation to even difficult or remote areas.


Popular Tank Sizes and Packages:

Part No.



6 1,500 0602 5'-11" 7'-6" 9'-3"

4,500 0606 5'-11" 22'-3" 23'-11"

9 3,400 0902 8'-11" 7'-6" 10'-1"

5,100 0903 8'-11" 11'-3" 13'-10"

10,000 0906 8'-11" 22'-3" 24'-10"

12 15,200 1205 11'-11" 18'-6" 22'

15 9,500 1502 14'-11" 7'-6" 11'-7"

23,500 1505 14'-11" 18'-6" 22'-7"

28,515 1506 14'-11"
22'-3" 26'-3"

27 30,500 2702 26'-10" 7'-6" 15'

Approximate capacity. Usable capacity may vary ±10%. If an overfill-protection device such as a ball-float or flapper valve is installed in the tank, the actual tank capacity will likely be reduced.
2 Actual tank dimensions may vary due to fittings, accessories and slight differences in construction. Consult specification sheets for accurate dimensions for use on installation planning.

3Standard Package includes
  • 3/4 Horsepower 4-stage stainless steel pump
  • High Strength G115 Galvanized Steel Water Tank Shell
  • Durable 30 Mil Potable PVC Liner
  • Geo-textile Pre-liner
  • Side Roof Access
  • Roof Ladder (on tanks 12' diameter and larger)
  • Top Roof Manway
  • Inlet Leaf Filter Basket
  • 6" Overflow Assembly
  • 2" Bulkhead Fitting Assembly
  • 2" Outlet Valve
  • Seal Strip
  • All Assembly Components

Pro-Package Upgrade Available:

An upgrade is available for this system. The Pro-Package upgrade (Valued at over $1,590!) would include the following components with the system:

Maelstrom Rainwater Filter
Upgrade to a Maelstrom Rainwater Filter for rapid flow rates of up to 9,510 gallons (36,000 liters) per hour. It can be mounted many different ways, to best suit any application! Also includes custom mounting bracket.
RainFlo MHP75A Automatic Pump
The RainFlo MHP75A Automatic Pump is a durable, .75 horsepower pumping system with superior, quiet performance of up to 26 GPM and 65 PSI. Features auto-activation whenever water begins to flow from user demand and when water flow stops, the pump shuts off. Also features run-dry protection.
Polyslab Pump Cover
Upgrade to a Polyslab Pump Cover and protect your pump! Heavy-duty, each cover includes a matching base to keep the pump off the ground and shelter from the elements. This will help prolong the lifespan of the pump as well as hide the pump from on-lookers.

The LiquiLevel Plus Tank Level Indicator is a simple pulley and counterweight system with an indicator beside the tank, that slides up and down a guide wire, for easy level indication. A new and popular water tank level gauge.

Additional Optional Accessories:

Inlet Strainer Basket filters out large debris such as leaves and sticks before they can enter the tank.

The Rainwater System Controller- The Rainwater System Controller manages all of the functions required in a typical residential or commercial rainwater collection system.
RainHarvest 1.25 The Motorized 3-Way Backup Valve is controlled by the Rainwater System Controller and switches between primary and secondary water sources, allowing only one at a time.

Package pricing is only available as shown. No substitutions or refunds allowed.

RainFlo CGS Corrugated Steel Rainwater Storage Tanks are designed to be constructed onsite in minimal time with very minimal site preparation required. Most CGS models can be installed on a 6'' minimum thickness sand or gravel foundation pad.

RainFlo corrugated steel water tanks are used in a variety of applications, such as:

  • Potable Water Storage
  • Fire Protection
  • Irrigation
  • Rainwater Harvesting
  • Storm Water Retention
  • Wastewater
  • Mining
  • Agriculture
  • Industrial Processing
  • Aquaculture
  • Thermal Storage
  • Many other bulk storage needs

These features make our water tanks an ideal choice for your water storage needs:

  • High quality bolted steel outer shell
  • Wide range of sizes / Custom sizes
  • Resistant to extreme climates
  • Meets a variety of design standards
  • Experienced engineering team
  • Modular designs / easy transportation
  • Trained installation professionals
  • The best pricing in the industry

Corrugated Steel Water Tanks for Potable Water Applications:

Each RainFlo potable water tank is designed and manufactured to meet a customer’s specific requirements. A major benefit of ordering a RainFlo potable water tank is that it can be manufactured with materials that conform to the requirements of NSF® Standard 61 — Drinking Water System Components — Health Effects.

The National Sanitation Foundation (NSF) is a leading international organization that develops standards, and tests and certifies products in the areas of public health safety and environmental protection. RainFlo potable water tanks are manufactured with a liner that has been approved as conforming to NSF standards for drinking water system components, demonstrating once again that RainFlo is a pioneer in its industry.


LEED Credits:

Owners and designers of new construction and major renovation projects can use RainFlo Corrugated Steel tanks and qualify for points under the U.S. Green Building Council’s sustainable sites and water efficiency categories of its Leadership in Energy and Environmental Design (LEED®)(1) Green Building Rating System™.

#1: Water Efficiency Category: LEED Credits for Water Efficient Landscaping

RainFlo CGS water tanks can easily fit into a design that qualifies for water efficiency landscaping credits under the LEED Water Efficiency category (Credit 1.1 and Credit 1.2). The intent of these LEED credits is to limit or eliminate the use of potable water, or other natural water resources, for landscape irrigation. RainFlo CGS tanks are routinely used to collect and store captured rainwater or recycled site water, which is then used for landscape irrigation. Using rainwater and/or greywater instead of potable water is one way to reduce the use of potable water for irrigation. Using RainFlo CGS water tanks, a system can be designed to conserve as much as 100 percent of potable water for such purposes.

LEED Credits for Water Efficiency (WE)

WE Credit 1.1: Water Efficient Landscaping (Reduce by 50%)
WE Credit 1.2: Water Efficient Landscaping (No Potable Water Use or No Irrigation)

Intent: Limit or eliminate (50%) or eliminate (100%) the use of potable water, or other natural surface or subsurface water resources available on or near the project site, for landscape irrigation.
Requirements for Credit 1.1: Reduce potable water consumption for irrigation by 50% from a calculated mid-summer baseline case. Reductions shall be attributed to any combination of the following items: plant species factor, irrigation efficiency, use of captured rainwater, use of recycled wastewater, use of water treated and conveyed by a public agency specifically for nonpotable uses.
Requirements for Credit 1.2: Achieve WE Credit 1.1 AND use only captured rainwater, recycled wastewater, recycled greywater, or water treated and conveyed by a public agency specifically for nonpotable uses for irrigation OR install landscaping that does not require permanent irrigation systems.
Source: U.S. Green Building Council, November, 2007

#2: Water Efficiency Category: LEED Credits for Water Use Reduction

RainFlo CGS water tanks can be a component of many designs that would qualify for Water Use Reduction credits (3.1 and 3.2) under the LEED Water Efficiency category. Both of these credits have the same intent: to reduce the burden on municipal water supply and wastewater systems by maximizing water efficiency within buildings. Whether the aim is a 20 percent or a 30 percent reduction of water use, RainFlo CGS water tanks can be used to collect plumbing greywater and/or air conditioning condensate that can then be used for nonpotable applications, such as toilet and urinal flushing, mechanical systems and custodial uses.

LEED Credits for Water Efficiency (WE)

WE Credit 3.1: Water Use Reduction (20% Reduction)
WE Credit 3.2: Water Use Reduction (30% Reduction)

Intent: Maximize water efficiency within buildings to reduce the burden on municipal water supply and wastewater systems.
Requirements: Employ strategies that, in aggregate, use 20% (Credit 3.1) or 30% (Credit 3.2) less water than the water use baseline calculated for the building (not including irrigation) after meeting the Energy Policy Act of 1992 fixture performance requirements. Calculations are based on estimated occupant usage and shall include only the following fixtures (as applicable to the building): water closets, urinals, lavatory faucets, showers and kitchen sinks.
Source: U.S. Green Building Council, November, 2007


Optional Water Tank Accessories:

A goal at RainHarvest Systems has always been to meet the challenge of a constantly changing industry by meeting the functional requirements of system designers and owners. RainHarvest Systems meets that challenge with a wide and growing range of corrugated water tank accessories such as those listed on this page.

  • Inspection Hatches/Manways (Various sizes)
  • Inlet and Outlet Flanges and Bulkheads
  • Rainwater Pre-filtration Systems
  • Potable Water Liners
  • Ladders and Platforms
  • Ground-level Side Access Ports
  • OSHA Safety Cages
  • Ladder Lock-off Panels
  • Concrete Anchors
  • Fireman Thread Adapters
  • Cedar Wraps
  • Cedar Wrap Concrete Anchors
  • Level Indicators and Control Systems


Guide Specifications – Corrugated Steel Water Tanks:


The contractor shall provide a RainFlo CGS corrugated steel water tank as shown on the drawings. The tank size, fittings and accessories shall be as shown on the drawings. The water tank system components shall be manufactured by and/or provided by RainHarvest Systems.


  1. The water tank shall be a RainFlo model _________ with a nominal capacity of ________ US gallons. The tank dimensions are _____’– _____” diameter, _____’ – _____” eave height, and _____’ – _____” overall height.

  2. A RainFlo water storage tank is a water storage product that uses a corrugated galvanized steel cylindrical tank in conjunction with a liquid-tight PVC liner. The tanks are built with a conical galvanized steel roof. Tanks are designed to be constructed and anchored to a concrete foundation.

  3. The tank is designed to store water with a density of 62.4 lbs./cu.ft.

  4. Wall sheets are continuous 4” pitch x ½” depth corrugated galvanized steel with a minimum yield strength of 40,000 psi and a minimum tensile strength of 55,000 psi minimum yield strength for 20 and 18 gauge sheets. All heavier gauges have a minimum tensile strength of 50,000 psi and a minimum tensile strength of 65,000 psi. The zinc coating conforms to G-115 specifications. Wall sheets have a 44” nominal coverage. Wall sheets have a coverage length of 9’ 4-1/2” long. The wall sheets are connected with GR8.2 bolts along both the vertical and horizontal seams.
    4a. Vertical seams are punched for a staggered or double row connection at 2” on center.
    4b. Horizontal seams are a single lap connection with spacing of 9-3/8”.

  5. Tanks are supplied with anchor brackets which bolt at the vertical seams and the center of the wall sheets.

  6. Water tank roofs have a 30 degree slope, are made up of self-supporting roof sheets, and are designed for 15 psf roof snow load.

    The 12’ through 48’ diameter roof panels are triangular in shape and have formed structural ribs along the radial edges to provide stiffness and strength. The 12’ through 48’ panels extend past the eave to allow for drainage and are attached to the wall sheets with top ring angle sections that bolt around the entire circumference of the tank opening.

    The 15’ through 24’ diameter roof panels are manufactured from G115 galvanized steel conforming to ASTM A563 GR33.

    The 15’ to 48’ diameter tanks come with formed steel roof ladder rungs that bolt between the roof ribs of a single panel, extending from eave to peak.

    The center opening for the 15’ through 30’ diameter tanks the opening is 33” in diameter.

    Each 15’ through 48’ diameter water tank comes complete with one roof panel complete with an inspection hatch, to be located at the eave next to the roof ladder.

    The 21’ through 48’ diameter roofs inspection hatch is circular with a 20.75” diameter.

  7. Water tanks are designed for 94 MPH (150 KPH) wind speed, UBC Exposure C.

  8. RainFlo water tanks are designed for Seismic Zone 2A. Many tanks will meet higher seismic zone loading requirements. Check with RainHarvest Systems Engineering for specifications.

  9. All bolts and nuts are galvanized with JS-500 coating. Roof bolts are hex-head and have factory installed PVC washers under a wide-flange shoulder. Wall sheet bolts have slotted round heads for ease of installation and minimal interaction with the liner.

  10. All bolts meet SAE Grade 8.2 or stronger.

  11. The liner shall be made from a flexible PVC material capable of containing water. Minimum liner thickness shall be 0.025 inches. All seams in tank liners are factory welded. The liner shall be suspended around the inside perimeter of the tank structure at the eaves with liner clips.

  12. Enhancements to meet potable water tank standards shall be provided separately.

  13. Erection and installation manuals are supplied with each tank.


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