Rainwater Harvesting for Small Applications

How much water can I collect?

One of the first things to consider when deciding whether or not a rainwater harvesting system will help meet water demands is your collection potential. An easy calculation to determine your collection potential is below:

Yearly Rainfall (inches) X Roof Footprint (square footage) X .62 X .95 = Gallons

Note: When picking out a rainwater tank, do not size it to the total yearly collection potential as you will use water throughout the year. If you need help sizing a tank, please follow the link here.


Rainwater Filtration


Filtering the water off the roof is essential to giving you the highest quality, healthiest water possible--especially if it is a primary use of water for your application. The WISY Garden Downspout Filter Package will filter out any particles larger than 440 microns and can be mounted in-line with a downspout. Each filter is suited for up to 1,000 square feet of roof area.


Space is at a premium when it comes to small homes, that is why RMS has developed a rainwater filtration system with a minimal footprint and minimal electrical demand. This filtration skid will remove sediment in the water, reduce odors and discoloration, as well as eliminate bacteria in the water by way of the ultraviolet light. We take the guess work out of setting up a filtration system by mounting components and pre-plumbing the filters--all you need to do is plumb into and out of the skid and supply the power. 


Tiny House Rainwater Harvesting Package
from 2,275.00

This package offers all of the pre-filtration, pumping, and post-tank filtration elements necessary for smaller rainwater harvesting applications such as tiny houses, mobile homes, RVs, sheds, garages, and more.

The purification unit comes pre-plumbed and pre-wired, requiring only two plumbing connections be made and one electrical connection. This system is all powered by either 12VDC or 110VAC connections (choose below).

Number of Downspouts:
Add To Cart


Rainwater Management Solutions offers many rainwater tanks in all shapes, sizes and materials of construction. Below are a few rainwater storage tanks that we have selected specifically for small rainwater harvesting applications due to their size, portability and affordability. With water tanks, it is important to keep in mind the weight of a full tank and that your structure can support the weight of the tank: one gallon of water weighs about 8.35 pounds.

Rotoplas Tank


The cylindrical rainwater storage tank from Rotoplas is a great option for rainwater storage with a small footprint. 

Common sizes:

  • 200 Gallon tank: $230.95

    • 40" diameter x 42" tall

  • 400 Gallon tank: $350.95

    • 40" diameter x 80" tall

  • 500 Gallon tank: $399.95

    • 48" diameter x 73" tall

Norwesco Loaf Tanks

The loaf tank from Norwesco is rectangular option for rainwater storage with a small footprint, allowing it to sit flush against a wall.

Common sizes:

  • 100 Gallon tank: $250.75

    • 41" long x 27" wide x 30" tall

  • 300 Gallon tank: $455.80

    • 63" long x 42" wide x 30" tall

  • 500 Gallon tank: $670.45

    • 92" long x 48" wide x 31" tall

Fol-Da-Tank Pillow Tank

The pillow tank from Fol-Da-Tank is a good option for storage underneath a house or camper.

Common sizes:

  • 100 Gallon tank: $454.00 

    • 4'6" x 4'10" x 16" (+/- 6" filled)

  • 525 Gallon tank: $757.00

    • 8'3" x 5'4" x 18" (+/- 6" filled)

  • 800 Gallon tank: $865.00

    • 10' x 6' x 2' (+/- 6" filled)


Due to their size and origin, shipping costs vary for each tank. To order these tanks, please call us at 1-800-653-8337 so we can provide you with a estimate for shipping the tank!