Rainwater collection - anyone know of a GOOD, inexpensive roof washer?

[mikeathens]

I had this commercially produced "first flush" diverter that I got in a pinch because I was so busy with everything else. It has failed, and now I'm back to figuring out what to do. This thing was a plastic ball suspended by a stainless spring inside a PVC Schedule 40 tee...as the rain ran over it, it would fill with water and eventually drop over the bottom outlet of the tee, plug it up, and then divert the cleaner water through another tee located above it into the cistern. My stand pipe and the ball exploded this past winter when it froze due to not draining the way it was supposed to.

Back to the drawing board. My goal is to divert the first 15 gallons from each rain event to waste, and collect the rest. This should clean the roof of leaves, bird crap, atmospheric fallout, pollen, etc.

My idea is to have a 3" PVC drop pipe from the gutter to a 15-gallon HDPE drum. The drum will be fitted with a faucet at the bottom that I can crack open to slowly drain the barrel between rains.

At the top of the drum, there will be a tee. At the bottom of the tee, I'm going to construct a cage out of plastic, metal, or whatever I find that will work, and place a PVC blow-up ball from the dollar store, like maybe 8" - 12" in diameter. This should fill up the drum with the first flush of 15 gallons (along with bird crap, leaves, etc, etc,) float the ball up against the bottom outlet of the tee, and direct the rest of the rain event into the overflow to the cistern. Final cost:

$8 for used coke syrup 15-gallon drum
$6 for plastic faucet and bulkhead fitting from tractor supply
$1 for ball
about $30 for PVC pipe and fittings.

this might be a complete failure; the old "ball displacing the water trick" is the only thing I remember from fluid mechanics...any ideas or does anyone have a set up for filtering or having a fixed-volume diversion for roof water harvesting that didn't cost $200?

 

[rowerwet]

what is the point of the floating ball? if you have a 15 gal tank with a small drain, once it is full the water will run into your main tank and any dirt will continue to fall into the first tank. you will still loose some water through the drain, but unless you have a small roof it shouldn't hurt that much. I just have a pvc tee with a pvc pipe that drops to a ball valve, once the pipe is full the water runs out the side of the tee into the barrel, and anything heavy drops into the pipe and I drain it out after it rains.

 

[savageactor7]

Mike did you figure it out...I like to put in a cistern and would like to know more about yours ...thanks.

 

[mikeathens]

Wow...revival of an old post. I guess better late than never? Anyhow, yes, I did come up with something - and it's different from what I had originally planned (and much simpler).

I ended up getting a 30-gal plastic trash can from Lowes, 4" 90 deg. elbow, 4" tee, plus plenty of 4" PVC pipe. I constructed a bulkhead from ELECTRICAL PVC fittings, as plumbing fittings have a tapered thread. I'll try to explain this, and also try to remember to take a picture tonight to post here.

Bulkhead is placed about midway up the trashcan, and the tee is placed about 1/4 of the way from the top outside the can. The first 20-gal or so of rain water flows into the can. As the level rises, it reaches the bulkhead and begins to back up in the pipe. It then backs up to the tee, and then the water begins to flow out the teee and into the cistern. Maybe not the best description, but hope you get the point. The picture attached has the system on the left, just to the left of the red door.

What this does is collect the first 20 gallons, and then isolates this water from that flowing into the cistern. The goal was allow the collection of pollutants and solids without allowing mixing with the "clean" water once it starts to go into the cistern.

From what I remember, this whole things cost about $30.

 

[JustWood]

I have an open top 55 gallon drum with a window frame fly screen set on top to catch all the crap. Regular garden hose type valve screwed into one of the bungs on the bottom. Water plants and wash hands before entering house with this setup near the house .
About every other rain I attach 150' of garden hose to it which runs downhill to fill up a 330 gallon tank that sets near the garden. Works great.
Hose $23
Valve- scrounged one off an old water tank
Barrel Free
330 gal. tank $40
Fly screen free out of a dumpster

 

[savageactor7]

OK thanks for the update Mike.

 

[steviep]

check out the great american rain barrel company in thier picture if you look you can see window screen under the cover. I personally think they might work better if you leave the screen very loose to catch thr debrie.