Rainwater collection system

pashworth · Jan 25, 2009

Hey guys,
I am starting the design of my rainwater collection system. I haven稚 done that much research but want to run it past you experts first. Some data / info first;

I live in North West New Jersey
I want to collect the water for irrigation of my 60' x 120' vegetable garden
Size of roof area = 2200 sq. ft.
I need to install the entire system before the more extreme heat of summer arrives
- Collection piping from downspouts to holding tank
- Holding tank
- Pump
- Filtration system
- Line from tank to garden
- Irrigation system in the garden
Downspouts to holding tank location - 120 foot horizontal and 10' down
Tank to garden - 400' horizontal and 16' rise

I have not purchased any of these items yet, so I want to be confident that the item I get is the correct size, type or whatever it should be to last a long, long time. I am now getting to the point where I am replacing several items, weather it is the washer and dryer or a car, due to the old adage "Ya get what you pay for." So based on this I want to do it right.

The problem I am having is the tank type and the pumping / pressurization method and the filtration. I have looked at concrete septic tanks and the plastic type water tanks. The concrete tanks are cheaper by a few hundred dollars but I can more the plastic tank as need be so I don稚 have to stage the excavation perfectly for the truck to deliver the concrete septic tank.

Link to the plastic tank;
1400 Gallon Below Ground Cistern (TN1400WT)

As for the pump; Can I get away with an irrigation pump or do I need a well type pump and a well tank as I do in my home. I want to set it all to a timer switch and irrigation switches to water the garden in the mornings.

Well guys, any ideas or has anyone done this before?

Thanks,
Paul

MikeD74T · Jan 25, 2009

I don't know how rural your area is but Fire Depts in areas without public water systems, at least in NH, use cisterns near multi home developments. Most are concrete because there's less danger of them floating to the surface if emptied during periods of high groundwater. Since you probably won't be emptying yours if it's raining a lot it won't be an issue but you should be aware that tanks will surface on their own. Ask neighboring Fire Depts if they have cisterns & get the specs. You can scale to your needs. MikeD74T

Philscbx · Jan 25, 2009

As for pump, a shallow well would be fine going into a 60 gallon tank for reserve pressure of 40 psi. You could water w/o the pump cycling every 4 seconds. May have to label the system not drinkable. I assume it's a sealed system straight to irrigation system.

I have always wanted to make one of those.
Sump pumps could add to the tank as well, instead of down the drain.

tommu56 · Jan 25, 2009

I have a 1200 gallon cistern for my low yield well at my cabin

If you want to pick one up check this supplier you will save the freight

Fry's Plastic in Kresgeville pa they have 2 or 3 other locations and were cheaper than on line with freight

I do collect the rain water to flush the toilet but we bucket flush it. it will be plumbed in this year.

i use ibc tanks for above grade storage and transport IBCs and Totes

look around for used ones.

why do you need to filter the water?

you might want to build a roof washer to minimize the debris

go to Google groups and look for rain water groups.

tom

Egon · Jan 25, 2009

First thinks first; have you figured out how much rainwater you catch and how much you will need for the dry periods?

Southeast Alaska has areas where rainwater and cisterns are quite prevalent for domestic water supplies. There may be some information there.

DownspoutDan · Jan 26, 2009

What exactly are you collecting the water for? Is it just for irrigation? Are you going to run it into your house for the toilet/shower/washing machine? Making it drinkable? Those applications alone will help narrow down the type of pump and filter you'd need.
Also consider where you are placing the tank and how high and/or far you will need to pump the water. Putting these systems in can be an indepth, yet fun, project. I'd love to help you some more, but just need a little more info about your application.
Less than $1100 for a 1400 gallon cistern is a stellar find! Freight could run you almost $300... so it could really be worth your while to check out some local tractor or farm supply depots before you make your decision.
Also keep in mind (as I was really surprised to learn this) that eventhough the cistern is underground, it is common to find algae growth along the inside-top of the tank. You may want to consider an in-tank water purifier (ozone) or adding some bleach every so often. So long as you follow the guidelines with the bleach, it will be safe to drink or use on plants (bleach is in fertilizer after-all).
Anyway, let us know more about your plans and we can probably help you narrow down your options. I found a large cache of info relating to rainwater harvesting here: Rain Barrels, Rainwater Collection Tanks, Diverters & Harvesting Components