The idea of "being prepared" can involve so many things in so many different situations. The key is to ask yourself what you cannot, or do not want to, live without. For us, the answer is water.

Whether you live off-grid or in the city, having rain water catchment and a tank is not a bad idea, if only as a backup. Most urban water reaches the home using electricity, so if the power fails, so does your source of water. Furthermore, there are times when your pipes can freeze, again cutting off your water. If you have a tank on your property, you can, at the very least, go and manually get a bucket of water for general sanitation.

When providing your own water system - whether as your main supply, a backup or for fish or irrigation - the bulk of your efforts should go towards storage, or a tank, as that is the most costly part.

Plastic tanks are easy to set up, but they are very expensive in larger sizes. Concrete ones are durable, but ill advised for any beginner, as they are prone to leaks if not done correctly, especially where the walls and floor meet. We have found that the shell and liner system described in this article is by far the best option for us. It's cheap, easy (even for just two people), and quick.

For information about how to harvest the rain from your roof to fill your tank, see here. For further information on cisterns, click here. For the full article, click here.

Step 1: Dimensions

This article is based on a 16ft diameter, 4 ft tall tank, holding 6,000 gallons. However, you can alter the dimensions to fit your needs.

Round tank:

π (3.14) x radius x radius x height x 7.5 = gallons

(e.g. 3.14 x 8ft x 8ft x 4ft x 7.5 = 6028.8 gallons)

Square tank:

length x width x height x 7.5 = gallons

(e.g. a 18ft square that is 4ft tall will hold 9,720 gallons)

Liner Dimensions:

You want to make your liner a little larger than the tank's dimensions, so that it has some slack. Also make it 1ft taller than your tank's walls.

Even though a square tank is more efficient with space and thus your liner, we would unequivocally recommend going with a circular design. We have done both and the round one is far stronger and requires less work. Any money you might save on the liner for a square tank is negated by the extra strength you will have to add to the frame. If you decide to go square, bury the bottom 1/3 of the tank.
You can often find an above ground pool for pretty cheap at the end of the season around where I live... might not be good for potable water (might be ok, not sure), but for &quot;work&quot; water, might be something to consider. Get a good deal and it would probably be cheaper than the materials for this. Not as long term tough, but a starting point. The liner could be worth it by itself. <br> <br>Just a thought.
these would be great liners for irrigating or animals, but it is not rated for potable. Still, it is a great start, and those liners should last a long time out of the sun. Even new, they are considerably cheaper than a potable liner and should be considered as a viable option.<br><br>Thanks!
Nice Instructable. I am planning an off-grid installment. (buying land, building an efficient house, and getting away from everything.) With this, i know you want to keep sunlight out, but how about artificial lighting (ex. sunlight threw a bleach bottle, or candles)? <br>my idea is have a pool, aswell.
It depends on what you want the water for, but it is generally not a good idea to swim in water that you will drink. If it is for irrigation, then that's fine. The algae will eventually balance itself out, so a bit of light is not the end of the world. If I were to make a pool with this, I'd put a greenhouse covering, instead of concrete.
Are you not concerned at all about it freezing in winter? How would we handle that?
The surface freezes sometimes, but we do not live in a cold climate. For colder climates, insulate, bury, or possibly add a heater.
<p>&pi; (3.14) x radius x radius x height x 7.5 = gallons</p><p>Hi. I wanna ask. why is it u times with 7.5?</p>
<p>7.5 is to convert from cubic feet to gallons</p>
Got it. Its just a conversion unit ?
<p>Dear Sir,</p><p>I am very much impressed and wish to make , Can you please what material is pond liner , what are the specifications and where from do I purchase this.</p>
<p>Dear Sir,</p><p>I am very much impressed and wish to make , Can you please what material is pond liner , what are the specifications and where from do I purchase this.</p>
<p>How does the water taste? I wish to try this exact setup but in the ground. I have 2 roofs at my place. the tank will be behind the smaller roof approximately 5-10ft away -no issue there. The bigger roof is about 100 ft away. The only reason I would put it in ground is so the bigger roof can feed into it using(gravity) an in ground drain pipe that will be connected to the gutters. Unless you can recommend a better solution for water transport between the distances. Any help would be appreciated.</p>
<p>Thanks for the information. In my case not only the budget is important but also the required effort in construction. And definitely, avoiding to build the concrete base is a great advantage. In the past, I've built two albercas entirely with concrete: walls and the base, and the effort is incredible, more over to get the same volume of this water tank.</p><p>regards,</p><p>israel.</p>
<p>I'm considering in building a water tank next winter, following this design. However, I'm looking for an alternative material in order to not use a vinyl tarp (to lower the budget). Have you consider in using a waterproof painting over the metal material? If this solution were feasible, I suppose that a concrete base would be needed and some hitches in order to join the metal walls to the base. </p><p>What is your opinnion?</p>
The liner is the cheapest method. If it is not for human consumption, you can buy a pool liner, which is considerably cheaper.<br><br>The added cost of a concrete floor and sealing makes it more expensive than even a potable liner.
<p> If your life depends on that water,..so do hundreds of other lesser-prepared neighbors. I'd hide it in a garage or &quot;tool shed&quot; or....</p>
How much did this cost total?
<p>At least $582.00 dollars for the 5 sheets of galvanized panels alone. Shipping not included in that--and it will be a bunch, at least 50 dollars. You can't get these sheets at homederpo or lowes or tractorsupply. You may find it at a local contractor-hardware store for building real things vs inside house projects.</p><p>Metalsdepo has them for 120 each, and stainless is more expensive (http://www.metalsdepot.com/catalog_search.php?sear.... Since this instructable has you coat with primer and some rustoleum type paint, one might consider going with the regular steel sheets and save 115 dollars.</p><p>Rustoleum to cover that amount will be another 30-80 in paint depending on the options. </p><p>Tamper is best bought at a harborfrieght for 20 dollars because it's a flat dumb piece of steel on a stick. Same with all the other tools except for the drill bits. Assuming you are tackling this project, it may be best to invest in good solid (diablo, bosch, etc) drill bits, but every other tool in this instructable like brushes, one should try to acquire them as cheaply as one can and toss them if they can't be cleaned. </p><p>For the shovel and pick, again harborfreight. For the pick, dont' get a pickaxe, get a mattock pick with fiberglass handle $22. This is a great piece of tool for cutting roots and absolutely destroying rocks or prying them out. Mattock end is much more useful than shovel for clearing the tank foundation.</p>
<p>these metal panels cost about $50 each, and I bought them locally at a metal shop.</p>
<p>Hmm, the 3 online place I looked had them for over 120 dollars. I wonder what this is all about? I have never heard of online people ripping others off.</p>
<p>well, I don't know. They are simple sheets of metal, should not cost $120 a piece. It's just sheet metal, nothing special.</p>
<p>Just another thought to expand my last thoughts (sorry this is a long post)... but PVC is awful toxic. I would not line my tank with a pool toy. Rather, it would make sense if you're already investing in a DIY 6k gallon tank to use a better material such as polyethylene. The best material is actually a platinum-cured silicone, which is cost-prohibitive and also not available for this application, except as a spray-on or paint-on (in layers) application. For this I would recommend contacting smooth-on. They have food grade materials. Keep in mind, if you can find a material to act as the 'bladder' or 'lining', you may be able to find something that a food-grade silicone would adhere to, and you wouldn't have to coat more than 1-2mil I wouldn't imagine, to have really 'perfect' zero toxic, zero off-gas water.</p><p>Personally I cannot tolerate any kind of plastic smell in my water, so the choice is to spend money storing filtered water perfectly or perfectly filtering PVC tainted taint-water. </p><p>Here's more info on PSI for choosing materials to use as alternative bladders.</p><p>6000 gallons * 8.34 lbs/gallon = 50040 lbs</p><p>Inner surface of the tank 3.14159 * 96&quot; * 48&quot; = 14476.44672 sq inches<br><br>Base surface of tank = 3.14159 * 96&quot; ^ 2 = 28952.89344 sq. inches (base)<br><br>---<br>Total: 43429.34016 sq inches<br><br>50040 lbs / 43429.34 sq inches = 1.15221645 lbs/ sq inch</p><p>--</p><p>I think I did this correctly. You need a liner material that can handle this PSI x 2. (&gt;2.5 - 3 psi)</p>
<p>psi is water height (in feet) times .45. In this case, 4 ft x .45 = 1.8 psi. <br><br>This <br> liner was engineered for higher <br>pressure. I've used these liners to over 10 ft deep, and they can do <br>even deeper.<br><br>PVC toxicity is related to UV exposure. The parts <br>in contact with water are in darkness. The liner in this instructable is <br> rated for potable water.</p>
<p>Very useful info, thank you!</p>
<p>Total cost is about $1,600<br><br>The liner was $750 (including shipping)<br>The metal cost was $300<br>The roof was $250<br>Plumbing was $200 (including all pipe, fittings, etc)<br>Paint and general hardware - $100<br><br><br></p>
<p>If you are going to use for just irrigation and not for drinking water, you can save at least $500 and go with a pool liner. </p>
plus depending on where u live. the code inspectors might not like yr cistern being made of concrete. i.e. 1 bag of concrete mix is abut 45$ and will do a wall of / about 4 in. by 4in. by 4- 6 ft. by then , u'd wish u went with their set up
Nice instructable. I've never heard of doing this with concrete. Why didn't you use the fiber mesh and concrete/acrylic on the sides of the tank instead of the plastic liner?
because the liner is considerably easier and cheaper. You could make the tank itself out of concrete, but because of the forces involved, it would require considerably more concrete and reinforcement.
thanks a lot
Not to rain on anyone's parade, as it were, but some states have laws about what you can do with rain that falls on your property and no, I'm not kidding. Here's an article from LA Times - http://tinyurl.com/ye97nuc - about Colorado's &quot;water harvesting&quot; laws. <br> <br>The article's a couple of years old so things may have changed but if you're going to put in the money and effort to install a cistern it might be worthwhile to familiarize yourself with the applicable law.
where did you buy the liner and how much was it and about how heavy is it. <br>
Great job, and Congratulations on winning 1st place in the contest. <br>You had my vote!
Thank you to Instructables for giving us the opportunity to enter the Be Prepared contest!
Congratulations on winning the Be Prepared contest!
Congratulations on the grand prize win. You did a great job on your IBLE.
Congratulations for being the grand prize winner!
Congratulations on being a finalist in the be prepare contest!
thank you!
This is cool. How do you keep mosquitos and mold/algae out of it? Do you treat it? Do you keep it full all the time?
it is not full all the time, because it is fed by rainwater, and we have a short rain season in the summer. <br> <br>Algae/mold and mosquitos are kept at bay with the roof. Without sunlight, 90% of your problems with these things are taken care of (no food chain). <br> <br>We also filter the water before using it in the house.
this looks awesome, just can't help but notice how similar to one of those quick setup above ground pools it looks like. I'm not sure of the cost, but my mother bought one at walmart that is 24' round by 54&quot; deep for about $700. This gives me an excellent idea for my uncle's &quot;hippy shack&quot; he is trying to go green and this would give him water to do dishes/water gardens with.
yeah, those above ground pools are nice, but they don't have a roof, and the liner is not safe for drinking.
I'm confused as to how the water that falls onto the roof makes it into the tank. In the a later step (step #9), you coat the roof with Acrylic Concrete, is this a semi porous material?<br> <br> How does the rain make it through that, or inbetween the sides of the roof and the angle iron?<br> <br> And, about the angle iron, won't it eventually rust and/or stain/taint the water?
There is a small space in between the side and the roof. Because the roof sites on the inside of the wall, water is able to trickle down into the tank. The angle iron is painted with a water proof paint.

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