Need help with water storage

[suburbancowboy]

All the cabins where I am building my cabin use water storage tanks for their water.  It is a dry subdivision meaning no wells.  There are two community cisterns that are fed by one of the many springs that everybody gets there water from.  I already have a water trailer to haul the water to my cabin.  Before I start building in a few months  I need to figure out two things.  One where to put the water storage tank and two how to pressurize the water.  Also being at 8000 feet freezing water is always an issue. 

I can only think of two ways to handle the pressurization.  One is gravity fed and the other is a 12v water pump controlled by a switch.  Water needs will be small and all in the same corner of the cabin.  1 shower, 1 toilet and 2 sinks.  Any other suggestions would be great.

Now for the tank placement.  I have 15 feet on the uphill side to the property line.  About 25 feet on the east side.  On the south side is the septic tank and drain field.  On the west side there are lots of trees and the path to the bunk house.  It also a little on the downhill side.

Inside the foundation it is mostly dirt with a cement strip running down the middle for a frame for joist support.  So I have the option to dig down further to put in a water tank.  Another option would be to try and put the tank on the uphill side on the property line.  Another thought would be to put the tank on the corner of the foundation next to the parking area.  I need some ideas from you all that have been there and done that.

Attached are a few pictures to possible help with the ideas.

South side


West Side


North uphill side


Foundation - cement strip running down the middle


I thought I knew what I wanted to do but I am starting to second guess myself.
Ideas?

[muldoon]

I do not have alot of expertise in this, so others may have ideas contrary to mine.  However, if it was me I would want a large tank unpressurized - a large cistern, that is then pumped into a 100gallon or so pressure tank inside the house. 

Perhaps the hill might be a good location for a buried tank if it can gravity feed from the community cistern you mentioned.  Inside, a pressure tank handles the needs of the house.  It's pressurized and semi-temperature steady, or at least insulatable.

[MountainDon]

How many gallons do you want to store?

[glenn kangiser]

Some of the 12v pumps have a pressure switch built in.  No need to turn them on and off - just shut off the water faucet and they stop.

[MountainDon]

she's 5'11"



IF I had thought far enough ahead, and if I could have placed the tank in eactly the right spot, I would have buried the tank under the cabin and had that hand pump on the kitchen counter at the sink. With the tank buried we've had no problem with retreiving water with the hand pump. With temperatures outside down to zero degress the tank water came out of the ground at about 40 degrees.

This is a 325 gallon tank with manhole extension. Spherical tanks like this can be pumped dry, unlike other shapes. The typical buried loaf tank should never be left less than 25% full.

That hand pump was made to be easily removed and taken inside to prevent the valves in the unit from freezing. It's a couple minute job to switch on or off.

I would still have done the balance of the system the same way. That is a poly RV water tank under the sink, RV pressure pump that has auto shut off and supplies up to 2.8 GPM at roughly 40 PSI supplying water to the fixtures. We use an air compressor to blow the lines free and have a line to drain water back into the underground tank,

[rick91351]

Mountain Don where did you find your tank? 

[rocking23nf]

I wondor would this work in a really cold winter area, we get -30s C and even -40s C in the winter months. How much is a tank like that? Can the pump be moterized so you dont have to hand pump it every time you need water?

[suburbancowboy]

These are some great ideas.  I am thinking that I need a 100 gallons pressurized in or under the cabin.  Out side of the cabin I need a 1500 gallon cistern on the property for fire control.  I was thinking that I would put in a 2000 gallon tank for that and code says I can use the extra 500 gallons for water storage.  Then in the late fall I would just bleed that off and leave the tank empty in the winter.  I was thinking of putting this external tank in some kind of insulated box to keep it from freezing 8 months of the year.  The other 4 months it would sit empty.

[JRR]

I wondor would this work in a really cold winter area, we get -30s C and even -40s C in the winter months.

No water storage tank will work if frozen... unless empty.  The question is: "How to avoid freezing?" .... any tank will work when that is answered.
Is the soil "easy digging"?  How deep is the frost line?  Is an earth covered pit an option?
In my cabin location (Tenn), I just use plastic trash barrels that I pick up from Ace during their spring sale.  (I don't need the volume you need.)  Placed above ground, inside, they still freeze over ... but cheap enough to replace without much pain.  (I add a bit of non-toxic antifreeze to the toilet flush water.)  So far, no barrels have split.

[MountainDon]

1.   I bought our tank from Tank Depot.

2.   It was around $450 or so IIRC

3.   If the tank is deep enough in the ground the water will not freeze. That would be more or less the local frost level.

4.   That pump I bought is available in a model that places the valve body underwater. It cost about 4x as much. That would eliminate the priming and freezing of the shallow model I bought. Oasis Pumps

5.   A submersible pump could be used but I didn't want the expense of the pump nor the need of doing something to prevent the freezing of the pipe into the cabin. I our case with solar electric heat tapes, light bulbs, etc were not practical.

6.   When low volume was mentioned I used my own low use numbers. We can make 15 gallons last 3 days easy as a rule. No laundry and navy showers.

7.   Gravity flow works but keep in mind that you get 0.43 pounds of pressure per each foot of water head; for 20 psi you would need the tank to be about 46 feet higher than point of use.

8.   You can insulate a tank, but if it sits there with no heat source and no new warmer water entering the tank, the water will freeze. I am reminded of this every time we return to the cabin. It is usually colder inside the insulated cabin than it is outside. And it's below freezing in there most of the winter when it is not heated. Outside it was around 43 one day when we arrived. It was something like 23 inside and had gone down to about 19. The point is, I believe the only way to ensure no freezing, without adding heat in some form, is to bury below frost level. Aeration can help but that requires power as well.

[suburbancowboy]

Do you have a feel of how far down in the ground you would have to go to keep a hundred gallon tank from freezing.  I was thinking if it was a foot under ground I would be ok.

[Redoverfarm]

It would probably depend on the frost/freeze level.  In this area at least 18-24".  That would be to the top of the tank or highest water level.  Other areas it could be more or less. 

[MountainDon]

The water, or at least a good portion of it would have to be below frost level. We had some ice form in the top of our cistern when the tank was filled right to the top. I had to break the ice with a pole. After we used some water it never froze again.

[UUmom2many]

Can anyone recommend a good book on off grid water for home use? I'm getting so confused as to what we need. We got a quote for a well of $3500. I was interested in cisterns but ones that you can walk into for cheese curing storage.

[WoodSprite]

Can anyone recommend a good book on off grid water for home use?

Yep:  Cottage Water Systems: An Out-of-the-City Guide to Pumps, Plumbing, Water Purification, and Privies, by Max Burns.  First published in 1999, but there's a 2004 edition that's worth hunting for.

[Osprey]

Can anyone recommend a good book on off grid water for home use? I'm getting so confused as to what we need. We got a quote for a well of $3500. I was interested in cisterns but ones that you can walk into for cheese curing storage.

Depending on how deep your well is it could cost almost as much to set a pump in the well.

My 455 ft well was 5K to drill and another 3K for the pump, wire and piping.

[SouthernTier]

I need help planning for water storage, too.

I'm lucky enough to have a spring near the top of my property, with a good 40 - 60 feet of head down to where the cabin will go, so I'll have "free" water pressure.  However, this means that the cistern would have to be up by the spring.  I would think I would want the water line to exit from the bottom of the tank into a buried (below frost line, which means 4 feet for me) down to the cabin.  This could feed a pressure tank in the cabin for local storage.

Looking at the cisterns at the tank-depot link, it seems like all of them you have to pump out from the top.  Is there any non-aftermarket way of putting the exit from the tank at the bottom.  Obviously this increases the chance of leaks, but still...

I also was thinking of having a standpipe overflow, at least in non-winter, so that as the spring continues to feed the tank, it pushes water out of the tank so the water in there is always relatively fresh.

[glenn kangiser]

A completely airtight siphon tube could bring water from the bottom of the tank over the top as long as the tank was a bit over the height of the water exit and you primed the siphon tube one time.

The siphon tube would have to extend to near the bottom inside the tank, and would have to be re-primed each time the tank ran out.

[Dave Sparks]

Hey Glen,
35" of rain so far on my hill   The only caution I think of when using a siphon out the top is that if the water sits in the pipe too long, it can cook off and you might not want to drink that slug of water. I did not look at the link in this thread at what type of tanks the OP is using but the standard Snyder tanks up in this area are easy to add an extra 2" valve on.

[SouthernTier]

These have a 2-inch fitting already at the bottom:

http://www.tank-depot.com/productdetails.aspx?part=TN5128PT

But they aren't meant to be buried.

I am thinking of using one of these in the short term for non-winter only use (sitting above ground, just downhill fom the spring)

I want to have the spring water continually flow through the tank so it is always fresh.  I was thinking of constructing an upside-down PVC U-tube coming out from the bottom fitting, with the top of the U at the height of a full tank.  I'd put a vent there to prevent siphoning.  At the bottom of the U (the other end, not the one attached to the bottom fitting), I'd have a 2-way valve, one way directing towards the creek (waste) and the other way feeding the hose down to the cabin.

This is how it would work:

Once the tank gets full, it spills over the top of the U and flows (wastes) to the drain-to-creek exit.  So always fresh water in the tank.  Because of the vent at the top of the U, the tank remains full (never empties via siphon).  When I arrive for a stay at the cabin, I throw the valve the other way, and it fills up a pressure (i.e. with a diaphragm) tank in the cabin.  That supplies the cabin. 

Water will continue to flow into the tank, and the excess will have to overflow through the vent.

As I use water, the pressure tank  gets replenished from the hydrostatic pressure coming down from the tank up the hill.  Because of the diaphagm I continue to get the full hydrostatic pressure, without experiencing much of the friction loss flowing down the hose (unless of course I drain the cabin tank too much).

I think this would work.

[Dave Sparks]

It sounds great but testing can reveal other issues. If you have enough height you may not even need a pressure tank unless you have many water users.

[Pine Cone]

This is a 325 gallon tank with manhole extension. Spherical tanks like this can be pumped dry, unlike other shapes. The typical buried loaf tank should never be left less than 25% full.

That hand pump was made to be easily removed and taken inside to prevent the valves in the unit from freezing. It's a couple minute job to switch on or off.

I would still have done the balance of the system the same way. That is a poly RV water tank under the sink, RV pressure pump that has auto shut off and supplies up to 2.8 GPM at roughly 40 PSI supplying water to the fixtures. We use an air compressor to blow the lines free and have a line to drain water back into the underground tank.

MountainDon - I'm getting ready to put in what I think may be a similar system and so I have some questions about yours.

I assume that the manhole extension just lets you bury the tank deeper and have something to mount the hand pump on.  When you take the hand pump off is there some sort of cap that seals the tank unit? 

Is the hand pump is only for occasional use (fill up a bucket or whatever) while you have some sort of electric pump that moves water from your underground tank up to the poly RV water tank under the sink, or do you do that with the hand pump as well?

My last house had a well with one of those bladder pressure pump tanks in the garage which then distributed water to the house and yard.  Is there anything like that in your system? 

Anything that you would do different in you had to do it all over again?

[MountainDon]

Yes, the manhole extension is to allow the tank to be buried more than without one. The height worked out  fine except for now that there's 30-36 inches of snow on the groiund.   

That hand pump is the only pump. I did not install an electric pump with a line direct to the cabin. That's was partly because the cabin is left vacant during the freezing weather and that there is no grid electric power to use for heating purposes. Using an electric pump and water lines simply seemed too much to bother with because of the winter. Of course if we used it more in the winter time I would have to work around that.

We do not have a bladder/expansion tank in the system. Rather we use a 12 VDC RV pump designed to be used without an expansion tank.


What would I do different?   I'd bury the tank deeper and use a taller manhole extension.

Last weekend we experienced a freeze problem. It seems the water in the downpipe/standpipe from the pump into the tank, did not bleed down enough or fast enough and froze. All pumping the pump did was develop a really good vacuum.  Boiling water was insufficient to solve the problem. I have a fix in mind and will expand on that later in my cabin topic as I get it all sorted out.

[Pine Cone]

Thanks Don!

At least I don't have to worry about that much snow here near Puget Sound.  Hard to get more than a foot to stick around here, and this year snow was almost non-existent around here.  Had some come down, but no accumulation on the ground.

Rare for it to get below 20F here, although we did get into the teens this year, so I think a 24" manhole extension would work OK.  Originally I was thinking no extension or a 15", but the 24" should work fine around here.  No well right now on the property, but I have a neighbor who will let us run a long hose from his well so we can fill or top off the tank now and then.

[ntexastomm]

A good source of rain water harvest info I use (and it's free).

http://www.twdb.state.tx.us/publications/reports/RainwaterHarvestingManual_3rdedition.pdf