I have rain catchment systems on four structures; I harvest up to 186,000 gallons of water per year--we get an average of 30 inches of rain here in Comal County.  My system was developed and installed with the consulting help of Dr. Steven Grainger.  Here are some quick guidelines he had me think through when designing my two rainwater harvesting systems:

1. Direct:  Establish gutters, tank elevation for gravity feeds, and consider both wet or dry conveyance piping captures for my rooftop water.  I have both wet and dry conveyance.

2. Capture: Install metal roofs on structures; I have a series of sealed downspouts with three levels of filtering, along with an overflow system, that are installed at each catchment base.

3. Collection: Storage tanks can be as simple as a 50-gallon rain barrel, large plastic or metal tanks, or a complex array of linked tanks.  I have one 6,000-gallon and one 5,000 gallon poly tank for capturing water for my garden, and one main, potable water, metal, 50,000 gallon catchment tank.  My garden tanks are not linked and provide water just to my garden.

4. Storage: The tanks need to be able to capture and move the water where desired.  I capture rain water via a "dry piping" conveyance off of two out buildings for the garden, and I catch water for the potable, main tank, via a "wet pipe" conveyance, and then pump the water from the respective storage tanks to the points of use in the garden, guest house, and main house.

5. Use:  The garden water is pre-storage tank filtered via leaf guards on my rain gutters, I have "Leaf Eater" screens on my downspouts (mosquito prevention), and I installed "Maelstrom Filters" on my two garden tanks.  No other filtration is needed for garden use--plants love rain.  The potable system has the same three pre-storage tank filters as the garden tanks and then a post-storage tank filtration system that includes a "spin down" filter, 20-micron and 5-micron particulate filters, followed by water passage through a UV light filter that neutralizes any pathogens. 

6. Pumping:  Last, having post-storage tank "Walrus" pumps allows me to move water to different locations under high pressure if needed.  I can even wash my cars via captured rain!

​

Once you move toward capturing rain, like me, you become more "water aware" and look for new ways to use and more ways to store nature’s bounty.   My garden tanks--11,000 gallons--overflowed this year (2021) by June!   

Dr. Grainger and I watch and monitor Trinity aquifer water tables in the Comal Trinity GCD's 10 monitoring wells; we see them steadily declining, and we know that “water is the new gold.”