A Second Tank

Rainwater Tanks

In the post of April 17, 2008, I mentioned the addition of a second rainwater tank to the north tank farm.  It was actually purchased and delivered last spring and has been sitting on a decomposed granite pad since then.  Since we’ve had very little rain this summer (actually an official drought) there wasn’t a pressing need to get it connected to the rest of the system.  With Hurricane Ike, and a possibility for heavy rain, it seemed wise to finish the project.

second tank step 1I started on the weekend of Labor Day.  The weather was very hot — in the high 90’s or low 100’s.   The first step was to dig a trench between the two tanks.  Normally, I would save work like this until a mechanical trencher is available, but the distance was only 15-20 feet, and too close to the tanks to use a machine.  An “artisan” (that’s “hand made”) trench would be required.

Texas Toothpick

I’ve dug plenty of holes at Roy Creek Ranch, and it’s never fun.  There isn’t much soil (usually not more than about two inches of topsoil) and underneath that is a material called “caliche” — a kind of soft limestone that is “dig-able” with difficulty — mixed with harder rock. The technique is straightforward: clear the turf with a spade or trenching shovel, and then use a 40-pound “cinch bar”  (aka. breaker bar, Texas toothpick, digging spud) to break up the caliche.  This is back-breaking work, and it’s best to split it up, if possible.  Two four-hour sessions in the cool of the morning and the trench was done.  The good news is that it isn’t necessary to go very deep here — the ground never freezes below a couple inches because of the mild winter weather, and a six-inch trench is more than enough.  A tip: softening the caliche with a little water helps.

Softening the groundNext step, pipes.  As I mentioned in the earlier post, two connections were needed.  Each tank has a 2″ nipple at the base and another near the top.  This allows for simultaneous water use and fill.  The plumbing scheme required top-to-top and bottom-to-bottom connections, with some added ports and valves to allow for different filling and use “modes” (see the earlier post for more details).  I’ve done a fair amount of PVC plumbing, but 2″ doesn’t bend much, and it is a little more challenging to work with.

first pipe and valve

Lengths and connector angles really matter.  A connection to the bottom of the new tank was first, using a valve, two 45 degree connectors, and a compression fitting.  The compression fittings are really helpful.  Each side of the fitting grabs an adjustable amount of pipe with a collar and  rubber gasket.  They’re intended for making repairs in tight spaces, but are also handy for fine- adjusting pipe lengths.  I also added a “T” so that future connections are possible.  The blue handle operates a ball valve that controls water flow to and from the tank.

Because the pipe is nearly rigid, and the positions of the tanks are fixed, it was necessary to measure carefully and trial fit pieces before glueing them into place.  Another compression fitting at the old tank allowed for the fine adjustments pipe union compression fittingnecessary to complete the run.  This is the end that feeds the supply pump and pressure tank, so extra ports are visible in the picture.

A connecting pipe between the upper ports on the two tanks were completed the next day.  In addition to the upper port on the new tank, this pipe connected with the large ball valves on the old tank that were already in place.  Again, compression fittings on both ends allowed for fine adjustment of the  tank connections.  This run was much easier, partly because I had had some practice the day before, and partly because it’s a simpler run (fewer tricky angles to account for).  Pretty soon it was done.

both pipes inPlumbing completed, and ready for testing.  After pumping about 2000 gallons of water into the new tank, it was time to look for leaks.  Everything was tight.  I expected some settling with the added weight of the water, and decided to leave the trenches open for a week or so to make sure that no problems developed.  Everything was ready for Ike though!

And then he took a different track.  I am grateful that we didn’t have to deal with torrential rain and 100+ mile-per-hour winds, but a little rain would have been welcome.  Maybe next time.  Trenches filled and everything tight, we’re ready for the next rain! roof washer added


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