First Flush?- rain water collection

[farmboy05]

So I finally got a good deal on some 40-50 gal barrel by watching one of those buy/sell things on facebook. ($5 a barrel, no lid, bought 4) So now I'm planning my water catchment system for my garden. I know a lot of people do a first flush to catch the crud, and I looked at what's available out there but the standard system has a small constantly open outlet at the bottom for it to work right. Does anyone on here have this? Does it work ok? It seams to me that it would plug up a lot. I saw someone else posted a thread on here before and did a smaller 15 gal tank as a first flush and they way it's set up, seems like it would work well, but require a bit more of setup.

What are your guys' thoughts on the first flush? Even though it's mostly for the garden, our well water is VERY hard and our softener burns through salt pretty good so I wouldn't mind someday diving into the collected rain water for other uses some day.

Also, being an engineer, I can't help but try to 'come up with a better mouse trap' and scribble out similar style first flush to what's out there but one that would have a larger opening and would automatically open and flush out when the rain stops, and hopefully avoid the plugging issue if there is one.

 

[Wood Duck]

I have a rain barrel with no first-flush device at all. I collect all the water that runs off the roof. I find the water is pretty clear all the time. I do get some dirt or crud in the bottom of the barrel, so I dump it two or three times a year to flush out the sediment. I typically dump it before a good rain so it refills quickly. I wouldn't bother with a first-flush diverter.

I think the biggest advantage of a rain barrel is that I can very quickly fill the watering can by dunking it in the barrel, rather than wait for the hose to fill it. That doesn't sound like a big deal, but it is very convenient when I have to water.

 

[semipro]

The first flush devices I recall are a chamber with a hole in the bottom and a float that redirects flow to your tanks once the chamber is full.
I'm wondering if just elevating the drain orifice above the bottom of the chamber would keep the hole from plugging. If you made a removable bottom for the chamber you could remove the detritus that collects there.

 

[JustWood]

I just put some fly screen frames that I scrounged out of a dumpster over the top of my barrels.

 

[Hokerer]

Our rainwater collection system is for whole house water supply. Downspouts run through "leafeater" screens (about 900 micron) then piped to collection bucket with 400 micron screen and from there into the 1000 gal underground tank where the well pump is. No first flush diverter involved and everything's always worked just fine.

 

[CenterTree]

Our rainwater collection system is for whole house water supply. Downspouts run through "leafeater" screens (about 900 micron) then piped to collection bucket with 400 micron screen and from there into the 1000 gal underground tank where the well pump is. No first flush diverter involved and everything's always worked just fine.

Same here. Our home relies on rain water solely.

We have a cistern (5000 gal) which is a huge concrete chamber built under the front porch of the house.
All rain water is channeled into the tank directly. Goes through a debris/leaf filter first...

Then a shallow well pump (located inside) pulls the water in through a large sand "filter".

We do have a whole house canister filter (50 microns) on the fore-side of the expansion tank in the basement and another filter after the pump/tank. (5 microns)

Never had any issues by not having a first-flush system on the spouts.
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Our garden rain barrel system collects all H2O off the shed. We have TWO 55 gallon barrels and no first flush diverter either.
The water just goes on the veggies anyway. We get a few bugs in it and some minor algae on the bottom throughout the summer, but no big deal.

 

[semipro]

The intended purpose of first flush systems is to remove dissolved contaminants not suspended ones. The first wave of water that comes through typically contains higher levels of airborne contamination as well as chemicals that leach from asphalt shingles, etc.

 

[farmboy05]

Thank you all! I am wondering though, do you do any kind of purification for using it for drinking?

I think I'll go straight into the 50 gal barrels for now, but maybe leave myself a way to add a first flush/material filtering if i need to down the line.

 

[Hokerer]

Thank you all! I am wondering though, do you do any kind of purification for using it for drinking?

Once it's pumped out of the tank, water goes through a 25 micron sediment filter then a 5 micron carbon block filter and finally a UV sterilizer and voila! potable water.