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 http://hurricane.ncdc.noaa.gov/cgi-bin/HPD/HPDStats.pl

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: http://wrcc.dri.edu/pcpnfreq.html

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 http://weather.msn.com/monthly_averages.aspx?wealocations=wc:USTX1200 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 www.raintankdepot.com

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.

Monday, May 3, 2010

Some Rain Barrels Options

Rain barrels, or as some know them, water barrels, can come in various forms and styles. For the DIY rain barrel it's important to start with a container that once held food grade material. Chemical containers or barrels could still have residue material tucked into crevices. Oak wine barrels may provide a nice appearance, but there is potential risk of water leaks down the road. Another important factor to consider when picking a rain barrel is the existence of a screen on the top of the barrel. Water entering a rain barrel should pass through a screen to filter out debris which could plug your hose at some point down the road. A screen is also critical to prevent your water barrel from becoming a mosquito larvae incubator.

In building or placing your rain barrel there are a few things to consider. First, fully loaded these barrels are extremely heavy. One does not want to set up a rain barrel where it stands the chance of tipping over. Second, in the event of leakage, one should make sure there is a path available for the water to travel so it doesn't do damage by flooding a structure, or causing soil erosian in a flower bed. Third, it's very important to remember that should you chose to not hook your tank up to some form of pump then these water barrels provide water via gravity feed. Rain barrels used in this manner may need to sit on a slightly raised surface, (i.e. concrete blocks or several layers of paving stones).

Accessibility and Availability

Rain barrels vary in size, shape and are made from a great variety of materials. Some rain barrels are designed to sit buried, while the more traditional rain barrel sits on the surface and is free standing.

More and more suppliers of rain barrels are popping up as this trend grows stronger. many hardware and gardening centers now stock one or more styles of rain barrel. A few minutes conducting an online search will yield a great number of suppliers who will arrange delivery right to your door.

The image to the left is a rain barrel made by RTS, and can be purchased at Rain Tank Depot stores which carry the RTS Home Accents line of products. The significant feature of this particular rain barrel is that it demonstrates how some rain barrels are now coming designed to fit flat up against a wall. Some manufacturers of rain barrels also provide inside corner rain barrels.

The Handytank
This is our favorite rain barrel for practicality reasons. This barrel is made from a heavy duty PVC bladder which is supported by a steel frame. When empty this rain barrel can collapse and slide easily into most vehicles. This tank comes in two different styles accommodating from 120 to 250 gallons of water.

EMSCO Rescue Water Urn rain barrel with built in planter has become a very popular and appealing tank due to it's ability to blend into it's surroundings, enhancing a garden and home instead of sticking out like a sore thumb.

While there are many suppliers of rain barrels in various countries and the texture, shape, color and holding capacity of these tanks vary greatly, these rain barrels above provide you with a good concept as to what you should look for.

We encourage you to take your time to research out which style of rain barrel or rain barrels would work best for you. The important thing is making the decision to conserve one of our greatest and most easily taken for granted resources- our water.

Monday, April 26, 2010

The Benefits of a Reverse Osmosis Water Filter

Clean water is a good thing, and reverse osmosis filtration is a good way to get good clean water. There are other ways to get clean, great tasting water. But reverse osmosis is a great way to get great water at a reasonable price. The price of a reverse osmosis system need not be prohibitive, and the pleasure and health benefits are considerable. The wide variety in size and style of RO treatment systems available put great treated water within the reach of most people.

One of the benefits people look for in filtered water is great taste, which really means the removal of bad taste common in municipal drinking water supplies. Filtered water makes better coffee, and that is mighty important to many of us. And if your city water has an unpleasant taste and smell, it isn't going to improve the taste of your cooking either.

Reverse osmosis home water treatments are available in a variety of installation packages, suitable for most budgets. There are counter-top models that will produce water for drinking and cooking. There are under-sink models that will produce considerable amounts of water, often dispensed through its own little faucet. Then there are the larger whole-house supply units, often installed in a basement. If you care to go to a whole-house treatment system, you get the benefit of RO filtered water in your sink, showers and bathtubs too. That will mean you are soaking and washing in clean, contaminate-free water rather than smelly city water. That's worth the price of a system, right there.

Reverse osmosis filtration systems are really a combination of several filtration treatments, including RO in the middle somewhere. A typical system might work something like this: A sediment pre-filter takes out the heavy stuff, all kinds of particulate matter from outright evil to merely annoying and filter-clogging. A second carbon filter removes chemicals and contaminates that make water nasty and might also damage the RO filter membrane, reducing its effectiveness. Then comes the reverse osmosis filter, which works by forcing the pre-treated water through a semi-permeable membrane, allowing nothing larger than a water molecule to pass through. Then, there may be final filtration through activated carbon, to assure sparkling clean water as a final product.

That's really water treatment by at least three filtration methods, but we still call it reverse osmosis treatment, and it's still a good thing. You can get small systems that you can hook up yourself. But you may want to consider having a qualified professional in to do the job. A pro can advise you on what's needed in your area, and then make sure the system is installed correctly to function properly.

Then, no matter what type RO system you choose, you can fill your glass with some of those crystal-clear ice cubes, pour the beverage of your choice, or maybe just some great water, and toast yourself for providing great water for yourself, family, and friends.

Monday, April 19, 2010

Residential and Commercial Rainwater Collection Systems

Sometimes a 50-100 gallon rain barrel just isn’t enough or you might not want to hook two or more rain barrels together. If you’re like me, you appreciate simplicity and if you’re looking to water your lawn with collected water, you’re going to need a much larger rain barrel than a traditional size. The Complete Rainwater Collection Systems are the largest line of easy to install, home grade rain barrels on the market. They come in above ground and underground and can contain anywhere between 214 and 5000 gallons of water at one time. Each size has different features that are unique to it, so there’s sure to be one that will work for you.

Designed to hold more water that the average rain barrel, the Complete Rainwater Collection System and Rain Captor above ground rainwater tanks come in red, green, and tan making it easy to coordinate with any decor. The smallest rain water collection tank in this category is the 214 gallon. This tank is designed for above ground use. It measures 69” long, 22” wide, and 45” high. When full, this rain barrel can pump out water from your hose for about 27 minutes. The next size up in the above ground rain barrels is the Rain Water Harvest Round, which comes in 300, 400, 550, 600, 1100, 1200, 1500, 2500, 2600, and 5000 gallons, which is our largest rain barrel.

Complete Rainwater Harvesting Cistern Systems are excellent for disguising a large rain barrel and still getting all the benefits. With these you won’t have to worry about coordinating with your d├ęcor or becoming an eye sore in your yard, you’ll barely even know it’s there. The underground systems come in 575, 1200, and 1700 gallons and can provide a constant flow of water for between an hour and two hours when full.

Although different in a few aspects such as sizing and included accessories, these rain water collection systems actually have quite a lot in common. Simple to install and compact enough for most household properties, they manage to provide an efficient, economical way to store large volumes of water. Easy to maintain and durably constructed; these systems are manufactured using a commercial grade polyethylene with UV8 inhibitors to prevent the growth of molds and algae. Each Rain Water Harvest Rain Barrel comes complete with a submersible pump so you can easily hook a hose up to the spigot and get enough pressure to water your lawn or garden. They also include a leaf catcher to prevent debris from settling in the tank. Also included with each rain barrel is a child safe lid so you don’t have to worry about a tiny wanderer falling in accidentally.

This specially designed rainwater harvest system will provide enough water to keep your plants healthy, your garden lush and green, your pool full, and you can even wash your vehicles with this naturally soft water. This collection of rain water harvesting tanks is an exceptional way to store mass quantities of chemical free, cost-free water for years to come.

Thursday, January 28, 2010


January 27, 2010

For Immediate Release


Cecie Harrington


Rainwater Collection Solutions, Inc

The Original Rainwater Pillow provides
Potable Water Storage for Haiti

Atlanta, GA - 1/27/10 - Rainwater Collection Solutions Inc, has donated a 1,000 gallon Original Rainwater Pillow to store potable water and a 100 gallon Original Rainwater Pillow to transport potable water for use by a medical team at the Hospice House Mathew 25 in Port- au- Prince Haiti. The medical team from www.ServeHaiti.org continue to treat residents and still have a large number of people staying on the soccer field. The team has also joined other medical groups in the surrounding community. Many patients were brought back to Hospice House Matthew 25 for extensive treatment.

The Original Rainwater Pillow is NSF approved and FDA compliant for potable water which means NO VOC's, leaching or off gassing from the material. The three part material provides excellent strength, UV resistance ( 20 + years ) and durabilty.

Other unique feature of The Original Rainwater Pillow is that they can be built to your custom size requirements up to 40,000 gallons.

The Pillows are light weight and economical to ship worldwide. This is a HUGE advantage over ridged tanks for disaster relief efforts!

Haiti pkgNick pkg

The 1,000 gallon Pillow folds up into a 36 " x 36" x 8" package and weighs 50 lbs

We look forward to supporting other relief organizations.
Cecie Harrington