425 Gallon Rain Tank

Permaculture Ideals:  – Hold water where it falls.
– Slow it down.    – Use it as much as possible.

Constructed Summer 2007



Every time there is an inch
(1 inch) of rain, there are 1,248 gallons of water coming off the roof of our 2,000 sq/ft ranch-style home.

2/3rds of the water drains off the front of our home (now captured by our rain gardens in the front yard) and 1/3 off the back.

During the growing season, all of the water from the back of the our home flows through this tank first.

We started with a 55-gallon drum but when it filled in about the first 3 minutes of a good rain, we knew we wanted something much bigger.




The tank is a common item found on ranches and farms which is made to slide into the back of a pick-up truck.

Because of it’s popular use, they make these by the thousands keeping the price affordable.  We paid about $225 for this tank.

At 425 gallons, it is the equivalent of connecting eight 55-gallon drums together.

Jesse (L) who is the son of our permaculture farming friends Bruce and Lisa at Fox Hollow Farm in Ohio, along with our son Hayden, helped us build the stand.


There is a large opening at the top of the tank where I laid in a piece of window screen to filter out small particles of debris and organic matter.

This is necessary to minimize fermentation or the souring of the water on warm days, and to keep the tank from clogging up.


I also found a stray piece of sheet metal that I formed into a collar or splash guard for incoming rain water from the gutters.

The two green rings I made from old garden hose and duct tape. They keep the collar pressed against the rim (to prevent it from blowing away) and bring things up to level with the top of the tank opening.


We cut and folded a piece of 1/4 inch hardware cloth to filter out the larger debris such as sticks and leaves.


It folded at an angle to encourage the debris to wash away as it collects.

Please Note: There are many ways to filter out debris…some better than this.  I’m just using the materials I have at hand to make something quickly that works good enough.

Feel free to share any good ideas you have on our networking site.


It was a few days before we had time to build the rack but in the meantime, it started to rain.

I quickly ran outside with my hack saw and shortened the downspout to be able to swing it over to the tank.

You’ll notice a couple of things. First, the large debris is being washed away from the screen as planned… and… the foaming you see here is the inability of the air in the tank to escape due to the volume of water entering the tank through the fine messed screen. Much of the water was washing away from the air rising out of the opening.


To fix this, I simply drilled some random hole in the very top of the tank to allow the air to escape.

When the tank is filling up in a good rain, you can put your hand over these holes and feel the air rushing out.


Here sits the tank with over 300 gallons of water in it from the earlier rain.

It certainly is a welcomed resource but being on the ground gave us very little head-pressure. When we attached a hose and small sprinkler we only got a 1-foot spray of water and the only things we could water had to be downhill from the tank.



So, after watering everything downhill from the tank we rolled it over to the other side of our house where we were constructing the elevation rack.

With this rack, the water tank is now up in the air and we have greatly increased water pressure.


When full, a 425-gallon tank will weigh well over 2 tons.

To prevent the rack from sinking into the ground we dug postholes down below the frontline (about 40 inches) and poured concrete pads for the legs to stand on.


Once the four holes are dug and the concrete pads were poured, the uprights were inserted and secured to be sure that they were perfectly upright.


A note about the concrete work…

I am not a skilled craftsman nor did I have any previous experience with concrete. The point being, if I can do this…so can you.

The concrete is purchased in premixed bags (40 or 50 lbs. I think) and all one has to do is pour the dry mix into a container and mix in water.

Here is Hayden (age 13) assisting me. He was a great help.



And here’s Hayden at 16 (May 2010). What a difference a few years makes…!


At the bottom of this hole is the concrete pad we poured (just one bag) the day before.

It is hard as a rock but still looks a bit damp from moisture.

The galvanized nails driven into the foot of the post is my extra insurance to be sure this whole thing never blows over.

Even if the concrete cracks over the years, and the posts become loose in the holes, they will not come out without pulling up all of the concrete with them.

That’s my thinking anyway.


Here we are pouring concrete in the hole around the nails.


A day later the concrete is now solid. We will backfill with the topsoil we dug out.


To support the tank, I placed six 2×6’s with standard hanging brackets to be sure it was well supported.

I avoided using a piece of plywood to make a smooth sitting surface for the tank since I knew it would get wet between it and the plywood and stay wet for a long time. I didn’t want to deal with rotting wood.


We purchased a brass ball-valve and attached a garden hose adapter.


To be sure there is no shifting we braced the corners.


Please don’t laugh at my hodgepodge of gutter attachments.

Bottom line is…it works!

The top of the tank opening is 3 inches lower than the bottom of the gutter so that the rain will flow freely into the tank.

We’ve blocked the downspout at the other end of the house so that all of the water goes into the tank at this end.

In the fall, I will raise the output end of this piece higher than the gutter and remove the plug from the other end of the house to allow the winter rains and thawing from filling up and ruining the tank (freezing can crack it).


A bit of brown silicone caulk keeps water from dripping through the joints.

(I know…it’s messy.)


Here is the other end of the gutter attachment. I have it secured above the hardware cloth about 1 inch to allow the debris to flush away.


Here’s a good look at everything two years later.

Hardware cloth at top, then the two garden hose sections, then the window screening.

I have to clean this out about 4 times a season.


In the spring, if we don’t have regular rains, the birds will build a nest.


In all waterworks design in permaculture we have to allow for overflow.

In this case, I simply cut a hole near the top of the tank and another in a section of downspout and attached it with screws.

When the tank fills the overflow runs down to Becky’s oak-water tank.


Here we are attaching some sideboards to the rack to help camouflage the tank.

I’m using some 1+ inch thick decking boards that should hold up for a long time.


And here it is, all completed and on a dry summer’s day.

Note the rain garden to the left of the oak tank. How do you suppose that fills up? And what will it provide water for?

Important to know… we do not have a basement. It is recommended that all rain gardens be a minimum of 1 1/2 times further away from the house than the depth of the basement to avoid seepage.


Stacking Functions
In permaculture we are always looking for a multiplicity of benefits to anything we design.

In this case, we now have three more uses we are planning for this structure. We will be growing grapes on the siding, mushrooms underneath to one side and we now have some extra, outdoor storage space.


This photo was taken during a light-spring rain (2010). You can see the overflow trickling out of the downspout and filling Becky’s oak tank.

(She loves being able to scoop up water after a rain without having to deal with the hose.)

When the oak tank overflows it fills up the small rain garden to the left..

And what is it watering at the corner of the rack?



A newly planted grape vine.


Bill Wilson
May 2010


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