How to: Build a Water Tower or Outdoor Shower

Posted on Mar 09, 2011 in DIY Projects, Urban Gardening, Farming & Homesteading – Kevin Hayden

Originally posted by unknown author as:

A Tower and A Shower

Setting up a water tower became the first major project on our Arizona homestead unless one counts the septic tank installation. While that (the septic) was being handled by a licensed contractor as required by Cochise County regulations, I got going on the structure that would eventually support a 500 gallon water storage tank.

Why 500 gallons? Why not 750 gallons or possibly 1,000 gallons? After all, even a small family can go through a lot of water in a week when you consider bathing, toilet flushing, laundry, etc. The answer was simplicity itself: Cost. A 500 gallon tank could be purchased online and delivered right to our door for under $400, and the dimensions of the one we actually purchased (64 inches in diameter, 42 inches high) also just “felt” right.

Since the camp trailer’s bathtub is being used to hold the food and water dishes for our household cats and the shower head itself has been gone for years, I decided to build the water tower with side walls that would serve to both (a) brace the support posts holding up the water tank and (b) provide a place to take showers.

You might say it’s a water shed (snicker!).

Step One involved planting four posts. These are 4″ x 6″ treated timbers, each 12 feet long. It would have made me happier to use 6″ x 6″ beams, but the local stores only stock that size in stubby 8 foot lengths. Boo. Hiss. No way was I going to spend the money to special order.

The posts are set roughly six feet apart in a square pattern with three feet buried in the Earth and nine feet above ground. 

The four treated posts in position. The horizontal 2″ x 4″ boards are temporary, simply tacked in place to stablize the posts momentarily.

Hayden’s Note:

This water tower project could be used for garden irrigation, drip irrigation, gravity-fed water options, outdoor showers, camping, rainwater collection or household use.

The Major Support Planks

Next came the planks which would do the most strenuous job of all, i.e. supporting a set of deck joists. Now, I know the definition of a deck joist, but what the dickens do you call the cross joist underneath the deck joist? (I figure a savvy reader will eventually tell me and thus save me the work of looking it up for myself.) Okay, so the definition may be elusive, but the job these planks have to do is quite clear. Every bit of water weight will depend on their strength, so they needed to be as burly as possible.

In the end, a pair of 2″ x 12″ planks looked like they would do the job nicely, especially after being attached to the posts with four strong 3/8″ bolts that ran completely through both plank and post and were cinched down with fender washers as well as lock washers. That meant drilling holes for the bolts, and that meant buying a drill bit long enough to do the job.

Note: This entire project was done without the use of so much as a carpenter’s square. I have one…but it’s hiding. A level was used constantly, though.

These planks were “green” lumber and therefore extremely heavy. When the first one (south side) went up, it was no problem: Just “pick a spot”, tack one end in place, and use the level to make sure the other end hits the right spot. But the second plank (north side) had to match the height of the other one, which was a problem. Since I work alone from necessity and by preference, I couldn’t just holler at my assistant to hold up one end. The solution: Leave one end resting on a lower “leveling” board while tacking the other end as close to the upper “leveling” board as the angle would allow. Then lift the lower end, “eyeball” the position, and tack that. Back and forth, until the plank was finally in the proper position as confirmed by use of the actual level.

I don’t ever build a project without the project itself changing my plans frequently along the way. This is not a drawback; it’s just the way I work. Two adjustments popped up by the time the heavy planks were in place and ready to be bolted.

Adjustment #1: Sixteen 3/8″ bolts had been purchased at Home Depot to secure the planks to the posts, figured at four bolts at each end of each plank. Just to be on the safe side, I’d paid for eighteen–two extra, right?

Wrong. Of the eighteen bolts, eight were the wrong size. Careless shopping, cowboy.

Okay, so put in what we had, get the rest later. That amounted to two of the posts getting two bolts each and two of them getting three bolts each. Plenty strong enough for the moment.

Adjusment #2: There were two other planks, 2″ x 8″ size, treated version, that were literally just lying around. I decided to just slap them up there under the 2″ x 12″ boards as extra reinforcement–but rather than go shop for more bolts, why not just nail them in place? After all, another leftover happened to be a number of 16d ring shank spikes. Five of those hammered into each end, and we were good to go.

The treated boards were longer than the others, but for now they’ll stay that way. Who knows? They may inspire a future addition to the shower shed which will house a washing machine or garden hoses or…you never know.

One thing I did know: For this particular project, the hard part was done.  Or so I thought….

A level was used constantly. This board is another “temporary” item, set in place only to make sure the support planks at opposite sides of the tower were installed at the same height.
The south side plank in position.
One end of the heavy plank (north side, second to install) tacked up “close” to proper height.
Both main support planks in place and the leveling board(s) removed.
“Extra” treated 2″ x 8″ reinforcement plank in position for nailing, held in place briefly by 2″ x 4″ braces.

Adding The Deck Joists

The next two boards were pure fun. All I had to do was slap them up on top, running across from plank to plank, and nail them firmly to the posts. How easy is that? True, the tape measure had to be used in order to be sure the ends stuck out evenly, and then a 2″ x 4″ board was tacked across those ends. Why? Because by “bumping” all of the in-between joists lightly against that board, the row would come out even with very little effort.

Then came a tricky little maneuver. Remember my saying that this entire structure was built without the use of so much as a carpenter’s square? All true. But when you do that, you can’t complain when the distance between posts isn’t exactly the same at the two ends. And they weren’t. Checking the distance and using a little simple division told me that in order to make the finished set of deck joists look evenly spaced to the naked eye–which is rather easily fooled, by the way–the distance between boards at the north end needed to be 5 1/4 “…but the distance at the south end needed to be 5 5/16 “. In order to make that happen, I cut two spacer sticks, one for each end, and stuck them in my hip pockets between uses.

Then, when nailing the joists in place with slick litttle gizmos called “hurricane hangers”, I’d check the spacing with the appropriate stick…and repeat the process, over and over again.

By the time all eleven joists were fixed in position, the support deck was really starting to look like something.

The two outside deck joists nailed firmly in place and the keep-’em-even board tacked across one end.
The handy dandy spacing sticks.
All eleven deck joists in place, view from the west.
Looking up!
From the topside….
…and one last looksee.

The Deck Floor

The deck floor itself was to be a solid row of 2″ x 4″ boards, each snugged against its neighbor as closely as possible without laminating the things. Despite the fact that unavoidable delays had left the green lumber out in the sun to warp for a while, this particular task promised to be the most enjoyable few hours of the entire project. There wasn’t much thinking or adjusting to do–just hammer in a few hundred 10d nails so that every deck board was firmly fastened to every joist.

Naturally, few things ever go quite the way one imagines in advance. As it happened, the last few dozen nails were actually hammered into place by flashlight. Add to that the discovery that 242 nails pounded with a 16 ounce hammer (rather than the 24 ounce framing hammer and/or nail gun most union carpenters would use)…that many nails were enough to make me notice an almost-strain in the right elbow tendon.

So? It was still a great day, and the basic tower was all set. Not ready for the weight of 500 gallons of water, of course. The structure still needed a few additions to possess sufficient rigidity for my taste. But enough to celebrate by moonlight with an extra cup of coffee.

The deck floor is good to go, finished last night afte dark.
View from the east.
Leaving the outer ends of the deck joists exposed was deliberate.
Such a pretty job; too bad it has to be painted!

Double Duty Reinforcement

Whether made of wood or (more commonly around here) metal, most water tank support towers display plenty of bracing. These braces are usually placed diagonally between adjacent corners. It made me grin from ear to ear to realize something: By using super-cheap strand board, available from Home Depot in 4′ x 8′ sheets 15/32″ thick at around $7 per, I could provide awesome bracing strength while at the same time producing a solid wall which would provide absolute privacy…and serve as a “shower shed”.

Note of amused disgust: Of course those boards went on sale after I’d bought all I needed for this project–yesterday they were down to $6.50! Happens every time…..

Once the strand board sheets were installed, the improvement in rigidity was obvious, even dramatic. Prior to that, you could stand on the deck, “wiggle” your feet, and make the whole thing sway enough to definitely feel it…north-south you could, that is. East-west, no: That direction involves both the larger post dimensions and the automatic bracing provided by those big planks. Now you could stand your basic 500 pound gorilla up there, wave bananas at him till he danced, and the thing wouldn’t so much as wiggle.

On the other hand, it was only at the last minute that I decided to add interior stud walls behind the strand boards. Yup, it’s usually done the other way around. Build your stud walls first, then add the sheathing. Like my late father used to say,

“Kid, you do everything bassackward.”

Yeah, Paw, but I still Get ‘R’ Done.

On three sides, the walls are six feet exactly, top to bottom.   About the time this much had been accomplished, the water tank arrived via motor freight. That the driver was able to find our off grid location was a true testament to my superior direction-giving abilities, but my salesmanship must have been rusty: I couldn’t persuade the trucker dude to hang out long enough to help me hoist the tank to the top of the platform.


The first round of wall boards (doing double duty as braces) are installed.
A section of interior stud wall.
The completed water tower just waiting for the water tank to climb on up there.

Finishing Touches

Details on how to lift a water tank to a water tower are provided in a separate hub, but the point is that the tank is now up there where it belongs. There are still a few details to wrap things up, namely a couple of stud walls, installing more permanent tiedowns, a lot of paint (the bare boards in the photos won’t remain unclad much longer), the vertically swinging door, and a platform on the dirt inside on which to stand while showering.

One key detail which escaped the photos: On top of the deck, the base of the tank is “enclosed” with eight pieces of 2″ x 4″ boards, a rough octagon, all nailed firmly to the deck. In other words, the tank can’t slide even a millimeter in any direction; it would have to literally “jump” out of its enclosure.

Bottom line? The tough stuff is accomplished. The incoming and outgoing water lines are both hooked up, an initial leak in the outgoing line has been successfully repaired, and–hooray!–the camp trailer now has running water. Or trickling water, at least; Pam has already pointed out that a few vertical feet of pressure don’t amount to a lot in a gravity feed situation.

For me, however, having even slowly running water to use when washing my hands at the kitchen sink is a true luxury.

The water tower, plumbed and in operation.

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