30,000 gallon modular, underground rainwater harvesting system

Find out more about rainwater collection at http://www.watercache.com/

Watch the entire installation process of a 30,000 gallon modular, underground rainwater collection system. These modular units are constructed onsite, wrapped with layers of geotextile fabric and a impervious liner, and then covered. This system can be stacked up to 5 units tall which is 7.5'. We installed a submersible pump in the storage volume and connected it to a pump start relay controller so the pump will only turn on when the irrigation controller signals the pump start relay. This system is collecting from roughly 10,000 square feet of collection surface and has the capacity to collect about 200,000 gallons of rainwater per year.

Category:

Education

Tags:

• rainwater
• collection
• harvesting
• cistern
• underground
• water
• eco-rain
• rain
• storage
• irrigation
• reuse

[ikambor]

i would hope that you would build a sand filtration system and pass it through it before that water makes it to the cistern otherwise you'll have an e coli stew in there before long

[iws2004]

@ikambor Since this system collects rainwater from the roof of the building, there will be a surprisingly low amount of bacterial pollution. In the tests we have performed on cistern water quality, the bacterial counts in the cistern water are very low. This is due to the fact that you only have birds that could be adding ecoli to the roof surface. If this system was collecting runoff from the ground or parking area, then you run the chance of higher bacterial pollution.

[philiphall2010]

would it be possible/feasible to do something 1/10th the size of this (say 2.5-5k gallon) for residential irrigation use? we live in an area where water costs are high especially for irrigation, and we also happen to have some pretty bad water retention issues. i have calculated the npv of our expected irrigation water bill for the next 5 years is in the order of $5000.

[iws2004]

@philiphall2010 You must certainly can install a small storage volume using this system. The material cost of a 2.5k gallon volume would be around $4,000. You would need add cost for the excavation and backfill, the collection pipes from your downspouts, and a pump system to use the rainwater for the cistern.

[iws2004]

@545Krinkify The system units can be stacked. The shortest unit is 1.5' tall and the tallest is about 7' tall. It needs about a 1' or so over cover over the system. I would not put this under a house. If you want to put a tank in the crawlspace of your house, you would want to look at a Rainwater Pillow (search online).

[iws2004]

@545Krinkify Hopefully you have a large backyard because at 30,000 gallons, this is a very large cistern.

[iws2004]

@davetileguy This block system provides a 95% void space ratio while well-graded gravel would only provide about 35% void space ratio. Gravel may be cheaper, but with the additional void space, the block system will harvest more rainwater over the life of this system.

Building an underground concrete structure can be very expensive. There are many things to consider with an underground structure. This block system makes underground rainwater storage very easy to deploy.

[davetileguy]

Wierd why not build cinder block walls poor a concrete roof? or rill with gravel?

[EarthREALTOR]

Yes, all the residential and commercial developments create so many large rooftops and large concrete and or asphalt footprints- impermeable surfaces- rain collection catches that water that would have fallen on that ground and returns it slowly, gently back into our beautiful Earth to replenish our aquifers. I live in Leander, a contributing zone to the Edward's Aquifer.

[iws2004]

@EarthREALTOR Thanks for the comment! Yeah we love our work and want to help people learn about rainwater harvesting and water conservation.