Rain water catchment newbie. Are first flush diverters necessary?

I am getting to install a rain water catchment system with 55 gallon barrels which previously contained honey. I get them for $10 a pop, and have a potential limitless supply from a local bread bakery.

The California drought has severely impacted me, since I started getting involved in permaculture about 4 years ago, I haven't had a year with average rainfall. With a normal year averaging 50+ inches, we now only get around 20-30 inches.

What little we do get, I want to be sure to catch as much as I can when it does finally rain.

One thing, do I need a first flush diverter?

If so, what is the best way (cheapest and most functional) to go about building one? A link to a nice tutorial would be helpful. The more pictures the better.

I'll be getting this done as soon as I feel like I have sufficient information, I'll be documenting this project on my instagram. Follow me at @centralcoastpermaculture.

Thanks.

How do you plan on using the collected rain water?
If you are planning on filtering it and turning it into drinking water, then yes absolutely put in a first flush diverter to make the water as clean as possible before running it through a filter. I collect rainwater to water plants and I just have it pass through a screen mesh to filter out twigs and leaves that get into the gutters.

They all pretty much work the same way the difference being what happens to the first flushed water. You can easily harvest the first flush in one barrel strictly for irrigation and have the rest cleaner for other uses.

This vid shows using a 55 gal barrel as a reservoir to hold the first flushed water for later use, the rest is cleaner and diverted elsewhere. You don't need to do this if the water is for irrigation only but it does help keep sediment from clogging up your water system over the years.
https://www.youtube.com/watch?v=ch-YsD9rOGk

Thanks for the responses.

I intend on using the water for irrigation only. So all I need is a particle filter? Some sort of screen? That's great news to me, building a first flush diverter can get expensive.

If I need to drink the water in case of an emergency, how would you recommend treating it?

Roy Hinkley wrote:They all pretty much work the same way the difference being what happens to the first flushed water. You can easily harvest the first flush in one barrel strictly for irrigation and have the rest cleaner for other uses.

This vid shows using a 55 gal barrel as a reservoir to hold the first flushed water for later use, the rest is cleaner and diverted elsewhere. You don't need to do this if the water is for irrigation only but it does help keep sediment from clogging up your water system over the years.
https://www.youtube.com/watch?v=ch-YsD9rOGk

Hey Roy, that is a very well done video. Thanks for the link. Do you have another link to show how to connect the storage barrels to one another?

I didn't mean to imply that was my video. Matter of fact now that I see it I think I would do it differently, cheaper and with no float at all.
I'll put something together later and post it for you.

To connect barrels.... the only big mistake I see is not using flexible lines between barrels. Things shift, barrels deflect when full all putting strain on plastic piping that cracks easily.

I live on catchment water, although I also have access to county water if I'm willing to truck it in myself or pay a water hauler to deliver.

I don't use a first flush diverter although I would always recommend it for anyone who asked me about catchment systems. Why don't I use one? The vast majority of my rain comes via drizzle and light rain. Thus the roof surface doesn't get washed off adequately in most of my rains. Even with a several hour light rain, I can still see ash, grit, the occasional bird feather, tree leaves sitting on the roof. So my water coming off the roof is "dirty" even at after the first 20-50 gallons collected. In fact, after a ten hour light rain, the roof appears almost as dirty as when it started.

People here living in really dry areas don't use first flush diverter either because every drop of water is precious. Our county periodically gives a free instructional class about catchment, and even they know not to waste time teaching about how to make and use first flush diverter to the Oceanview and Green Sands residents.

Just about everybody here screens the water entering their catchment tank. Usually some device at the end of the pipe -- a colander, a screen box, a woman's nylon tied onto the end of the pipe, or something to catch the chunks. No fine filters at this stage.

If using a pump to move the water from the tank, then a filter is needed in order to protect the pump. Another thing to do is to either situate the water outlet pipe 6 inches above the bottom of the tank or have a flexible hose with a float (such as an old 2 liter soda bottle) that keeps the intake about 4-6 inches beneath the water surface. The idea is not to suck up the fine debris that has settled to the bottom of the tank. Sucking that silt up will clog your filter in a hurry.

If you're just using trashcans/barrels or a small tank for short term storage and using it for irrigation, then not much else needs to be done to the water. But if the catchment tank is large and the water stored for long periods of time, then the water needs to be treated. I monthly check my water pH and chlorine level and adjust as needed. I routinely store over 30,000 gallons of water.

Covering the water to block light will deter algae growth. On longterm stored water, mosquito control is important. So that is something that needs to be addressed.

I use my catchment water for everything but drinking and cooking. I use county water that I bring in by the gallon because it is convenient and free. I pass the county water spigots six days a week, so it's no problem for me. But if I were to use my own catchment water for drinking, then I would need to sanitize it is some fashion. The maintenance bleach would not be enough. Most people here opt to use a UV light system. And before the water reaches the UV light, they install a fine particulate filter. There are other ways to sanitize water, but this is the common method here.

As for drinking water stored in plastic, I'm not too fond of that idea for myself. I store my drinking water in glass containers.

Here's how you can make a fast first flush without a float. Just make sure the vent pipe is above the feed line.
After the reducer I would put in some flexible line the reason being that when you drain the barrel you want to rock it a bit to agitate any sediment in the barrel so it flows out.
Box stores have large diameter clear reinforced plastic tubing that would work nicely.
Plastic barrels have one fitting that is a large pipe thread (1-1/2" or 2"). Use this for the feed line keeping everything as large diameter as possible.
The other has a funky thread with a fitting that has a 3/4 pipe thread, use the 3/4 as the vent again using flexible tubing, garden hose would be fine here.

Especially if you will be using buckets to deliver water, you don't need any kind of treatment other than enclosure to keep mosquitoes out, if that is a problem for you. sediment will settle out and in an emergency you could carefully take clear water from the middle of the barrel and drink it boiled assuming low atmospheric pollution. Or you could use a Berkey filter, which i highly recommend and use at home for all drinking and cooking water. My family and I collect rainwater without first flush, pump it (from clear middle area of catchment tanks) into our indoor tank through a 10 micron filter for bathing and kitchen washing and use the berkey filter for drinking and cooking water. If you set up a gravity flow irrigation system you also don't need any treatment, if you use a pump you might need some sort of inline screen or filter depending on pump specs. I tie window screen around my submersible pump in my low cost minimal home system.

I don't really see the need for a diverter. Anything on your roof has been baked in the sun and been laying in the open air for a long time and is not going to hurt you. Tie a ladies nylon onto the end of the pipe, let the fines settle out and enjoy.

Years ago we used roof water in a fairly small house (under 1000 sq ft of roof) to provide drinking and cooking water for 8 people, a dog and a cat year round. We probably got about 20 inches of rain a year and were never short of water.

If you have a dead cat on the roof or birds have been roosting up there that first flush isn't really going to do it for you anyway. You need to inspect your roof periodically if your collecting drinking water off it.

I collect rainwater from my roofs in daisy-chained IBC tanks. I did a very simple first flush filter to catch the heavier solids. It's illustrated in this post. The water isn't used for drinking.

If I was using rainwater for drinking, I'd draw it off and stored it in an unglazed pottery container. Rainwater is very 'new' and 'live'. It will strip minerals out of everything that contains it ... including your body.

wendy.... that s thing. rainwater is basically destilled water with more or less air pollution in it.

what about slow sand filters? will they do a good job to remineralize water?

i read a survival book years ago. they used pits with tarps to destill and collect water from the ground. then they put sand into the water, stirred and let it sit

I'm guessing that might work well too. Just a different mix of minerals.

I hadn't heard about rainwater pulling minerals from your body. Maybe that is why in the old days they would sometimes put a bunch of limestone or marble gravel in the bottom of rainwater cisterns. I had a guy telling me about it years ago say it kept the water sweet. Exactly what that meant, I don't know.

I hadn't heard about rainwater pulling minerals from your body. Maybe that is why in the old days they would sometimes put a bunch of limestone or marble gravel in the bottom of rainwater cisterns. I had a guy telling me about it years ago say it kept the water sweet. Exactly what that meant, I don't know.