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water tanks, metal, potable?

Posted: Tue Oct 07, 2014 1:18 am
by gandalf23
This past weekend we lost power for 36 hours. I'd just bought a new 275 gallon ibc tote to hold drinking water, which we did not need, but my wife was glad we had it. I was talking with some extended family that have well water, and they lost power, so they lost their water. I suggested they get a ibc tote, too just in case.

But then we got to talking, and they have a friend of a friend with a metal water tank that was off a water truck. 700ish gallons. Roughly four by nine. Not aluminum, maybe stainless? (not sure how to tell, not sure if there is still a manufacturers plate on it) He only wants $300 for it. Which is about what I paid for one new 275 gallon ibc tote. I thought that was a great idea for water storage: the metal tank should last longer outside, not degrade in sunlight like the plastic does, and should be repairable by welding if it does spring a leak. But my dad, a civil engineer, said not to use it as it would not be good for potable water. He did not explain any further, and he's out of town right now so I don't want to bother him, plus he was a little snippy about it.

So, is there a problem using an old water tank like that for potable water?

I also found a guy selling some aluminum water tanks from military trailers, that we then used by volunteer firefighters for off road water haulage, would those be alright for potable water?

Is the holdup that they'd need to be cleaned good, or what?

Are plastic bladders available that would fit inside? Or would the interior need to be coated in something?

I'm finding lots of "don't ever use aluminum tanks because alzheimers!" but I thought that got debunked a few years ago.

It seems like boats use aluminum and steel water tanks.

Any thoughts?

It's cheap enough I kinda want to buy the 700 gallon tank anyway, and if it's not useable for water bury it in the backyard for an instant storm shelter/wine cellar. :)

Re: water tanks, metal, potable?

Posted: Tue Oct 07, 2014 1:25 am
by randy
If the 700 gal tank isn't actually contaminated and just does not meet whatever standards for potable water, I would think at the very least it would make a reservoir to feed a purification system. And to fill buckets to flush toilets.

of course you're going to want to use it up and refill it regularly.

Not at expert but following with interest.

Re: water tanks, metal, potable?

Posted: Tue Oct 07, 2014 3:18 am
by JustinR
Tractor Supply (as well as other farm stores) carry heavy duty polyethylene, UV-stabilized, black (for reducing sunlight transmission and algae growth) potable water rated storage tanks in a variety of sizes. They have PVC compatible attachment points for valves and pipe. I bought a used 1,000 gallon tank a few years ago for $400 and build a concrete pad to be able to hold two. Eventually I'll put gutters on my house and pipe it to the tanks, with a home made roof wash box that dumps a preset amount when it starts to rain. (Eventually a UV and carbon recirculating filter, pump, and garden spigots as well.)

Unfortunately, I'm clueless as to the suitability of metal tanks for potable water. :?

$300 can get you slightly more storage capacity than 700 gallons if you're willing to look at used and put together the piping.

http://dallas.craigslist.org/dal/grd/4695551710.html
http://dallas.craigslist.org/mdf/grd/4694318655.html

Re: water tanks, metal, potable?

Posted: Tue Oct 07, 2014 3:29 am
by BDK
Not sure about aluminum. Dairy grade stainless holds all manner of beverages - but it is a very specific alloy and polish and cleaning regime.

Re: water tanks, metal, potable?

Posted: Tue Oct 07, 2014 3:49 am
by Aesop
Image
The military uses metal tanks, and has for years. So do thousands of farms going back forever.

Steel or aluminum, how to tell: Get a magnet. (Duh! :P )

A solution of ordinary unscented no other additives household bleach, 1:100, should adequately clean and sterilize the innards. Put one cup of bleach into 99 cups of water (which is 6.18 gallons of water, BTW. If you put a cup into 5 gallons for convenience, that'd be stronger, and wouldn't hurt anything, or you could put 1/2 cup into 3 gallons, same-same.), presto. Spray it thoroughly on the interior, leave it there for >10 minutes, then thoroughly rinse it clean with fresh water.
Assuming it doesn't leak, it's now ready for use.

Were it me, I'd plumb it such that fresh water is piped in at the top and drawn out at the bottom, with valves at each end, to seal it off at your choice and convenience. If you can/care to plumb a purification and/or softening filter set up at the incoming end, so much the better. (Really high-speed: If seasonal freezes are an issue where you are, a solar water-heating set up to keep the tank and piping from freezing in cold months, ideally in some small supporting and insulated shed. You don't need it to be at 72 degrees, 33 or better is sufficient, right?)

Worst case, it'd be a 700 gallon cistern to draw from with any food-grade pump, even a hand pump, or a spigot (with the tank set above ground at least as high as above the top of a 7 gallon food pail/military water jug, for ease of drawing, because you're smart!) and while you might need to filter it again for absolute safety, you'd be starting with water a helluva lot cleaner than anything else. For you + one, that's nearly a full year's supply at a survival bare minimum of 1 gal/person/day.

Even at typical household use rates that are 100x that, 700 gallons is a 3 1/2 day cushion for two people during any future water outage, allowing full normal use of bathroom, laundry etc. (Presuming you have a pump that can pressurize your system after you shut it off from any outside supply lines. Otherwise, you're hauling jugs/buckets. A little red wagon, trash dolly, or garden cart is your new friend: 5 gallons is a 41# load, plus the container wt.) Pretty good stuff IMHO.

So hell yes, I'd install and use it in a heartbeat.



As an inhabited shelter? Hell no! :o
Confined spaces like truck and railroad tanks kill people regularly.
If you decide to re-purpose it, you'd more likely want to use it as a sealed storage cache, and if you put stuff in or retrieve it, you want to open it and ventilate it with fresh breathable air for 10-20 minutes before entry, and even then, only with someone standing by outside just in case.
(Who could drag your unconscious ass out in an emergency, via a handy rope and winch. 4 minutes w/o air = brain damage, 6 minutes = all the way dead.)
People who go into vaults like that alone may not always come out.
And a 700 gal. tank would likely be too damned small to want to get into for more than a few minutes anyways.

You can turn a metal can/tank into a shelter, but realize you've essentially created a submarine, so you need to be able to bring in, handle, and remove fresh and stale air, and that people exhale water vapor, so humidity, condensation, dampness, and mold all become a problem in such conditions, followed by respiratory infections and other nastiness, not least of which are things like Legionnaire's disease. Submarines are for people with nuclear reactors, large diesel power plants, or other lotsa-power capabilities, plus humidity control, air filtration and cleaning, and UV lights to kill the bugs.

Hope that helps the thought and planning process.

Re: water tanks, metal, potable?

Posted: Tue Oct 07, 2014 4:48 am
by arctictom
I use a 2k gal plastic tank , its about 2 feet under ground , works great , their about 1500 bucks here should be cheaper there . Metal potable water tanks are usually stainless , and should not be a problem either , just bleach them out to clean them.

Re: water tanks, metal, potable?

Posted: Tue Oct 07, 2014 8:16 am
by evan price
Around here, IBC's from food-grade are available readily for less than $50. The portability of an IBC, to me, is more to my liking than a giant metal tank that has to live somewhere permanently. I can move a FULL IBC tote with my forklift if I need to, and an empty IBC moves by hand.
If that metal tank is stainless, the scrap value is more than $300, so I would assume it is regular carbon steel of some sort. There should be a fabricator's data plate on it, look in areas near the valve ports, behind an access door, etc. because the data plate by code needs to be readily visible.

Re: water tanks, metal, potable?

Posted: Tue Oct 07, 2014 9:47 am
by Termite
Galvanized steel cisterns holding rainwater were used in the South for...............a long time.

RE using a secondhand tank for storm shelter: Confined space entries are for specifically trained and equipped personnel. Generally a bad idea for Joe Sixpack.
If you want an underground storm shelter, install/build a real one, not a secondhand southern redneck "presidential-engineered" one.

Re: water tanks, metal, potable?

Posted: Tue Oct 07, 2014 1:01 pm
by gandalf23
I'm a bit leary of used totes for drinking water if they don't have the label of what was in there on them, and most of the ones I looked at off craigslist had the labels removed. Sure, the sellers all said it was safe, but who knows. That's why I got a new bottle in a used cage, from Questar over off Regal Row. $225 plus tax, IIRC. http://www.questarusa.com/hazardous-was ... ibc-totes/

I will be getting some of the used food grade totes for rain water collection for use in the gardens. Because they are much more portable than these metal tanks, and I can lift them and position them myself without needing to borrow the bobcat.

But the steel tanks would be for people with a farm, so the size and having to use a tractor to move it is not a problem. They've got tractors and a bobcat. I think they are wanting to plumb one so that water comes up from the well and into the tank, then out to the house or wherever, so there is always fresh water flowing through it, and if the pump breaks, or they lose power, they've got 700 gallons worth of time to fix/replace it.

I couldn't bury the tank on my property anyway as we are on Austin chalk. We've got maybe four inches or dirt then it's rock down for a few thousand feet. Makes for a great foundation, but non bueno for digging holes.

I'm going to look at the 700 gallon tank on Friday it looks like, so I'll look for a nameplate and see what I can find.

Thanks for the cleaning instructions Aesop!

Re: water tanks, metal, potable?

Posted: Wed Oct 08, 2014 5:40 am
by gandalf23
Went ahead and got one of the aluminum tanks for me to use, not sure if the folks with the farm will get one, but I think they're going to get the 700 gallon one.

It fit in the bed of my pickup, sorta. I don't know why Ford changed the size of the bed, but my 2011 F150's bed is narrower (and taller) than my old 1976 and 1994 F150s.

Anyway, got it home, got it unloaded, and will be cleaning it out soon.

Scrubbed off the gunk from the nameplate, seems like it was originally a gas tank. It's too dark to take a picture of it, and I did not write down the tank info, but it said it was for petroleum products and there is a reminder that gasoline weighs 6.4 pounds per gallon.

Is this going to be a problem?

The tank was used by a volunteer firefighting group, so probably untold gazillons of gallons have been flushed through it. I did not notice any funky smell.