Monday, September 19, 2011

Rainwater harvesting from start to finish (final cost $1.26/ gallon retained)

I've put together this post regarding a residential rain tank system we just installed here at our humble abode on the upper Texas coast.

As usual, this is a noncommercial post. I provide extensive sourcing here, but no corporate entity has provided any financial consideration in exchange for being cited.


When researching stock tank gardens a year ago, my challenge was that there was almost no relevant information on the internet - I had to invent a system.

With rain harvesting, I had the opposite problem - an overloadof information, an avalanche of greenie propaganda, and umpteen million commercial rain harvesting vendors, applications, and configurations that simply were not relevant to my specific goal, which was a volume-effective but easily-managed system at a rock-bottom price that an ordinary urban or suburban homeowner could DIY in a weekend or two without the need for specialized skills or tools. So once again, I've been forced to think through a new type of application here, but in response to a very different challenge.


Friday, April 29, 2011

Lower Pricing on Water Wall

The Contain Rainwater Harvesting Wall is built with quality in mind. Our new tank is built from the highest food grade plastics available and is made with 100% recyclable materials. We stand behind our products and offer a lifetime warranty "Water Tight For Life"

The Contain Rainwater Harvesting Wall can be used as a free standing privacy fence, wall attraction, living wall, water shed and will essentially be adaptable to the wildest imaginations because of its flexible size.

The Contain Rainwater Harvesting Wall is a dual sided tank leaving the end user with two different cosmetic options.
1) Beautiful rock wall look with modern touches.
2) Generic look with shelves for flower pots and or whatever you decide should be stored.

Now see for new LOWER prices!

Wednesday, January 5, 2011

Rain Harvesting Expo & Workshop

Join Us to learn all aspects of Rainwater Collection & Harvesting.
Programs will cover everything from simple rain barrels to complete, complex systems.
All your questions answered by certified rainwater collection pros. Huge discounts and a free gift for all attendees.
The event is slated for Saturday, February 5th 2011 from 11:00 a.m. until 6:00 p.m. at the Tank Depot in San Antonio. Tank Depot is located at 2620 SE Loop 410 (that's the Rigsby exit) in San Antonio, TX. You can call (210) 648-3866 for directions.
Special appearances are scheduled by rain harvesting stars and ARCSA (American Rain Catchment Systems Association) Certified experts such as:
Joe Wheeler • Rain Filters of Texas
Dick Peterson • Environmental Consultant and Rain Harvesting Expert
Esequiel Flores • Garden Irrigation Workshops
Tamarah Sunday • Rainwater Resources
Wade Kolb • Hydro Catchment Systems
For more info, visit

Tuesday, August 10, 2010

Rain Water Harvesting Basics

by Joseph Tyson
Mr. Tyson is a member of ARCSA

How much rain may I expect to harvest off my roof?
There are several factors to consider in calculating the water storage potential of your system.
>Average annual and monthly rainfall totals
>Median annual and monthly rainfall totals
>Rainfall Intensity
>Rainfall frequency

For most cities, rainfall data is available from the National Climatic Data Center at

Don’t forget to consider your climate – many northern locales are subject to rainwater harvesting systems being shut off in order to prevent freezing. Large sections of the US experience precipitation in the form of snow and ice. You’ll need to know the amount of annual runoff in addition to precipitation levels.

Intensity of rainfall is measured in inches of rain per hour (IPH). IPH is an important factor in designing your system as it will affect choices of first flush, filters, gutter and downspout sizes and collection techniques. You will find IPH info along with other similar rainfall data

Consider how frequently you will experience rainfall. For example, areas of Washington State may have some rain fall for as many as 80 or 90 days consecutively. Conversely, sections of the Southwest may experience zero precipitation for many days on end, followed with rainfall intensity rarely experienced elsewhere.

Rainfall return period indicates the inverse of the probability that a precipitation event of a certain magnitude will occur in a one year period. For instance, a storm with a 10 year return period has a 10% chance of occurring in any given 1 year period. You may find more information here:

The simplest calculation of the number of gallons of water that may be collected off any catchment area during a rainfall is as follows:

Catchment (roof) area in SF x Rainfall in inches x 0.623 x Runoff Coefficient* x Safety Factor **

Runoff coefficient – different surfaces, based on texture and porosity, will affect the amount of water that will successfully runoff into your collection system. Gravel, rocks, asphalt shingles, concrete, for example, will all retain some of the water that you aim to collect. Rainwater harvesters uses this table in calculating catchment potential:






Metal, Gravel, Shingle




Concrete, Asphalt











Safety Factor- any design makes allowances for an overestimation. The safety factor that you use will be reflective of how important the water that you collect is. The family relying on harvested rainwater for drinking water, crop irrigation and the like will use a safety factor much greater that folks who are using harvested rainwater solely to irrigate landscaping. Consider a safety factor between 0.65 (on the high side) and 0.95 (on the low side).

So, let’s look at a simple example-

Roof area (always measured in square feet at the drip line) = 2,500sf
Rainfall in inches = 2.75
Runoff Coefficient = 0.95 (for our example we will assume a high runoff coefficient)
Safety factor = 0.95 (we will be using our harvested water to irrigate our landscape)

2500 x 2.75 x 0.623 x 0.95 x 0.95 = 3,865 gallons

Surprised? Most folks are.

Let’s take a look at how much water a San Antonio, TX homeowner might expect to harvest on an annual basis. First, I go here to get monthly average rainfall data and use it to compile a table (MS Excel is an outstanding tool for this exercise)

























As you can see, the total rainfall in San Antonio, TX averages just 31.34 inches of rainfall annually. Let’s take a look at how much water the roof of a 3,000 sf ranch home in San Antonio can expect to harvest.
Our home is 60 feet by 50 feet, with a 2 foot overhang all the way around. So we calculate our catchment area as 64 x 54 = 3,456 sf. Our roof is a Spanish tile. We will be using harvested rain water for landscape irrigation and, perhaps, to wash our automobiles. Let’s calculate:

3,456 x 31.34 x 0.623 x 0.95 x 0.95 = 60,899 gallons!

Once we determine that we have the potential to collect over 60,000 gallons of water in a year, the next thing we must determine is how much storage capacity do we require?

We'll discuss that in the next post

Friday, July 16, 2010

Contain Aboveground Rain Barrel

Rain Tank Depot is happy to introduce our latest Rain Barrel- the Contain Aboveground Free-Standing Modular Rainwater Tank Fence!

The Contain Aboveground measures only 7.5" thick and goes virtually unnoticed along narrow pathways or fences. Collect rainwater for use in your gardens, irrigation or washing your vehicle.

The Contain Aboveground has the ability to perform as a free standing fence, water shed and can be mounted on all angles. A variety of alternative applications prove to be great under decks, custom benches and area segregations. The Contain Aboveground has been designed to withstand the hot summer sun and has a UV stabilizer added -UV8, the maximum UV protection for polyethylene.

In your search for the perfect rainwater harvesting tank please ask yourself this question before you make your decision: Are you comparing tank only prices, or have you looked at the cost of transportation and installation as well? When comparing larger tanks to the Contain Aboveground, it is important to take into account the total cost of ownership with both solutions. The Contain Aboveground is designed to be inherently "greener" than its competition: it is easier to handle, transport and install, it is reusable, and it is 100% recyclable. This added durability and usability costs more upfront, but once you add delivery and especially installation, as well as maintenance to the larger tanks the cost difference suddenly changes.

The Contain Aboveground is an architecturally designed unit that has been made of the highest quality plastics. It is visually discreet, structurally robust and can be installed on any of its sides. If you are looking for a long lasting quality product which adds value to your home, and requires virtually no on-going maintenance, there is no comparison between the Contain Aboveground and alternative options. Collect rainwater for use in your gardens, irrigation or washing your vehicle.

Each tank holds 58 U.S Gallons of rainwater and can be easily expanded to any size required. The Contain Aboveground is available in Rivergum Green or Beige to easily blend into its surroundings. Affordable and easy to install. This system is perfect for the environmentally conscious homeowner.

Purchase the Contain Aboveground Rainwater Tank Fence at

Wednesday, July 14, 2010

Save $150 on Aquadra Rainwater Tanks

Visit Rain Tank Depot today and save $150 on Aquadra Water Tanks!

The Aquadra Systems’ modular rainwater collection tank’s unique design is large enough to hold 75 gallons of water, while also keeping a low impact on the exterior appearance of your home. It comes in a variety of colors and can endure all weather conditions.

The Aquadra Tank comes with a kit and full instructions on how to securely mount the unit onto your house, fence, garage, etc. The kit contains non-proprietary parts and items that can be found in any hardware store should you need to replace any bolts or hookups.

After the Aquadra tank has been secured, all you need to do is wait for the rain! The down spout from your home’s gutters will divert to the top of the Aquadra Water Tank. An average house roof can collect 75 gallons of water in about 14 hours.

The Aquadra System Specs:
  • Length: 12inches
  • Width: 24 inches
  • Height: 72 inches
  • Weight: 50 lb (empty)
  • Storage: 75 Gallons

Although these are the standard colors, the Aquadra Water Tank can also be ordered in any color you wish!

Visit Rain Tank Depot today to take advantage of getting this great product for the lowest price around!

Wednesday, June 2, 2010

California Middle Schools Get Wet with HOG

Rainwater HOG is bringing water conservation out of the garden into the bathroom for students at Hall Middle School. Working with green plumber Jamie Rogers of Rogers Remodel, we recently installed three HOGs at Hall Middle School in Larkspur, California. The three HOGs will flush the sixth grade girls' toilet for 7 months out of the year. This provides over 8,000 gallons of annual water savings.

HOGs are also heading into San Francisco's McKinley Middle School with 7 HOGS used on their long sides to irrigate the school's new native garden.



Rainwater Hogs and Rainwater Hog Installation kits can be purchased at Rain Tank Depot.