Reply To: TANKLESS UNDERGROUND WATER HARVESTING

[mark foster]

 

To expand on Mark’s point:  the “pondless waterfall” people have done a lot with this concept, and we have used this technology on several rainwater storage projects. Here’s another type of pump chamber to look at:  http://www.savio.cc/pond-products/C55/  . 

The advantages to an aggregate filled system is the stone provides a lot of mechanical filtration protection for the pump–they are long-lasting and foolproof.  The disadvantage is an approximate 50% reduction in the water volume due to the stone.  

Other things to consider:  

1.  use non-treated rubber (most roofing rubbers contain anti fungals–you want to use the ones meant for ponds)

2. use non-reactive, ph-neutral stone, (we use river rounds, but they are not available/affordable everywhere)

3.  make sure the pump and water delivery system is meant for grey water (that small particles can pass through it). 

4.  Aggregate size is important–too small and it will trap sediment, too large and it will not filter.  We have found using mixed sizes of stone between 1 1/4″-3″ diameter to work best.