There are numerous tank options available. Rainwater Resources™ chooses from only those engineered to the highest standards and customizes the exact tank preferred for each application.
This article provides a basic overview of the various tank types available.
Fiberglass tanks are built in standard capacities from 50 gallons to 50,000 gallons and in both vertical cylinder,and low-horizontal cylinder configurations. Tanks for potable use have a USDA-approved NSF certification. Fiberglass tanks are primarily used in below ground applications.
Standard polypropylene tanks are one of the most common and economical choices for above ground storage. They range in size from 12 gallons to 15,000 gallons and are manufactured in a variety of shapes and styles. These tanks are durable, lightweight and long-lasting.
In-ground polyethylene tanks are more heavily construction. Most in-ground tanks use a ribbed design to providethe support needed. Although, additional cost is required for excavation, in-ground polyethylene tanks are a great choice as they are light-weight, come in numerous sizes, and provide a more seamless integration.
For aesthetic appeal, a wood tank is often a highly desirable choice for above ground rainwater harvestingstorage. Wood tanks, similar to wood water towers at the railroad depots, were historically made of redwood. Modern wood tanks are usually made of pine, cedar or cypress wrapped with steel tension cables, and lined with a USDA-approved plastic liner. These tanks are available in capacities from 700 to 37,000 gallons, or customized tanks up to 1.5 million gallons. These storage tanks are generally built onsite.
Another option to give the look of a wooden tank is to install an above-ground
polyethylene tank and install a wooden wrap around the outside of the tank. This gives an aesthetically apealling look, with the ease of a polyethylene tank.
Galvanized sheet metal tanks are also an attractive option. They are lightweight and easy to relocate. Most tanks are corrugated galvanized steel dipped in hot zinc for corrosion resistance. They are lined with food-grade liner, usually polyethylene or PVC, or coated on the inside with epoxy paint.
Concrete tanks are either poured in place or prefabricated. They can be constructed above ground or below ground. Poured-in-place tanks can be integrated into new construction under
a patio, or basement, and their placement is considered permanent.
Concrete may be prone to cracking and leaking, especially in underground tanks in clay soil. Involving the expertise of a structural engineer to determine the size and spacing of reinforcing steel to match the structural loads of poured-in-place concrete cistern is highly recommended.
For potable systems, it is essential that the interior of the tank be plastered with a high-quality material approved for potable use.
Stone and Mason
Handmade stone or mason tanks are not as common as they once were. Increasing labor costs, decreasing costs and increasing availability of other types of tanks has limited their use to areas where labor is very, very cheap (i.e. third-world countries) or where budget is not an issue.
The mass of the stone gives these tanks two distinct advantages: It keeps the water cool in hot climates and they can be very attractive. As with ferrocement tanks (tanks constructed of mortar over a wire mesh that has been preshaped over a mold), care should be taken to make sure the mix does not contain toxic materials.
These tanks are custom-built, so they can be as large as designed. Most tanks are designed to be circular, since this shape is more structurally sound. These tanks, if properly constructed and maintained, will last for decades.
Modular style underground storage is not a tank in the traditional sense, but rather an underground chamber created by a series of plastic modules wrapped in a waterproof liner before backfilled with earth. The modules are supplied as separate components for economy in shipping and ease of handling, but are easily assembled. Access pipes can be attached to any top module for access, inspection, and cleaning.