Underground 1200 gal cistern install

[ntexastom]

The drilled well quote was $9500 so we went with a rain water cistern and filter system for our 20 x 30 1.5 story. A long slow dig by hand but lucky for us our soil is soft sandy loam.

[rick91351]

Hey!  Well done!  From some one that has taken on something like that by hand before, enjoy the victory!  You Won!  Others that never have done so will never have a clue!

[seedspreader]

What will keep the tank from floating when the ground is saturated?  Is that a concern?

[rick91351]

From what I have read and been told you have to keep some water in them to keep them from floating.  Easy way to do this is locating the foot valve or pump pick up that far from the bottom.  I would guess the tanks engineering department could tell you the magic amount down to the liter or gallon.

[ntexastom]

Correct, specs call out to keep 150 gallons in as a weight. Our sandy loam soil drains well so that helps also. It has not moved that I can tell in a year so far so good.

[glenn kangiser]

Good job.   A few questions that may help others.

I am assuming steel roof with about 750 square feet coverage?

How often do you get rain? 

How many inches per year?

How do you pump, filter and treat your water?

Thanks for the great info.

[Squirl]

Great job.  You are lucky you are in Texas, because you don't have much of a frost line to deal with.  I recently researched this option as a few limiting option for water.  Ohio puts out a good illustrated walkthrough of the NSF guidelines for potable rainwater.  Do you have any codes or laws to deal with?  Will you share the rest of the parts of your system design? Thank you for the great pictures.

[ntexastom]

Thanks. I'm in rural Oklahoma so no building codes but I'm trying to smart about what we build. I used Texas rainwater harvest guide as a planning tool www.twdb.state.tx.us/.../rainwaterharvestingmanual_3rdedition.pdf

Basically my area gets about 41 inches of rainfall a year so I found historical monthly totals and just made a spreadsheet with roof sq ft, collection, usage etc. I used 35 gallons per person per day for usage, which is low but we have had a travel trailer there for 2 years and have proven we can get by on less than that when we try.

As far as the rest of the system goes I do not have all the parts installed yet but the plan is cistern, jet pump, pressure tank, sediment filter, charcoal filter, UV filter then inside faucet. I will post pics when I get it done.

[Squirl]

Another great guide.  Thank you.  Most people I have talked to seam to go with the UV instead of chlorination. 

[DirtyLittleSecret]

This is EXACTLY what I've been wanting to do up at the cabin...any additional photos you could post up while moving forward would be much appreciated.  Unfortunately for me, we have a 36" frost line (which means digging deeper than my shovel will reach), and have a bunch of trees (which means my shovel doesnt stand a chance).  Then again, I guess thats what track hoes are for!

[MountainDon]

Just a FYI... as far as I know all underground storage tanks require a certain minimum amount of water to be left in them to prevent flotation issues. Sometimes as much as 25% of the volume. Refer to manufacturer.

Spherical tanks, usually limited to around 500 gallon, are the only ones I know of that do not have that requirement.



I like the idea of UV much better than adding chemicals.

[ntexastom]

Finally got west side downspout and roof washer plumbed to cistern. A month AFTER the rain season. One step at a time. Next up will be east side downspout, pump inlet and two overflows.

[UK4X4]

Now I have to ask,

why did'nt you carry the brown presentable pipe to ground level and then use the poop tube ?

Also should not the over flow be just below the top of the tank ?
and not half the way up the house .

ie water will be exiting the tank lids way before it gets to the overflow


Please I'm not plumber - so could be barking up a completely wrong tree !

[ntexastom]

The brown downspout is not water tight so it would not work as a roof washer. What looks like an overflow just above ground level is just a top off access to add hauled in water. The real overflows will be on the cistern itself installed above the inlets.

[duncanshannon]

very cool!  Like glenn said.... How do you pump, filter and treat your water?  have you figured that part out yet?

[keyjoy]

Where did you get the tank? I mean bought locally or online? How much was it?
Right now, we are using 10 55 gallon plastic barrels, but for the new house we are looking for a tank to bury. Great photos Thanks

[Dave Sparks]

From decades of drinking water out of tanks (boating around the world and 10 years in the hills near Senior Pacifico Glen)  I have learned the biggest mistake people make is being overly concerned about treating their water in their tanks.  The key is treating the last few inches of water when the tanks are empty!

Test kits are easy and cheap!

[ntexastom]

Finally got carbon filter and UV installed. Next weekend we'll pressurized the system and hope...

[ntexastom]

1/2 HP jet pump from Tractor Supply sitting on a horizontal pressure tank. I think I paid $975 for that 1200 gallon cistern at Tank-Depot.com. Picked it up in in Shawnee Ok @ Norwesco distributor.