Although solar-heating systems are minimized by clouds, whatever warm water is obtained can be passed into the regular household water heater to save heating costs. In other words, if you know you're going to need a solar heater sooner or later for troubled times or just as insurance against the future unknown, the sooner you build or purchase one, the sooner you can have it paid off while you can still use gas.

It would be very nice to have a solar heater that can withstand household pressure, which always runs its water into the gas water heater. In that hot-water tank as you now have it, if you still own one, cold water entering the tank is needed to push hot water to faucets. It therefore adds cold water to the hot tank. Assuming that the cold water is 55 degrees, a water tank starting with water at 125 degrees will drop to 90 degrees after only half of the tank water is used. Soon after that, the shower water gets unappreciated. But if we always ran the roof-tank waters into the gas heater, in the warmer seasons, anyway, we would save a lot of gas. It just makes sense. If we can't afford to purchase a solar heater, then why not build one?

It is possible for ten people to go a long way into the trib with a 250- or 500-gallon tank of propane used solely for body washes (not laundry) and cooking. This should be the trib survivors primary line of defense for heating water, but having some solar-heated tanks installed can make that propane go a lot further.

There's no reason that hot roof water can't be passed through a tankless water heater. I own one now. Its problem is that its flame strength needs to be set (by me) according to the temperature of the incoming water. In most households, incoming ground water is usually at a similar temperature year-round, but if the incoming water is sometimes the groundwater, and sometimes warm or hot from the roof, the shower temperature is going to be unpredictable, always changing. We will need to set the flame high enough to heat the ground water, but when hot roof waters come in instead, we will need a lot of cold water at the tap to cool it off. Isn't that a sorry waste of energy, to heat the water high, only to cool it with cold water a few seconds later? I try to set my flame, and usually succeed, so that I add no cold water at all.

In other words, in a trib situation, the tankless heater might prove to be one giant headache if we couple it with solar-heated waters. It should be better to use the roof water direct, with a second showerhead coming out or off the ceiling, for there's a good chance it won't have pressure i.e. no spray.

For some aspects of this discussion, it's going to be assumed that the trib survivor has sufficient electricity with solar-powered batteries for running a water pump.

If you forego the insulated storage tank, then you like to suffer. Unfortunately, you can't take showers with your warm clothes on when the roof water is on the chilly side. Without a storage tank, you'll be taking your water directly from the roof tank, which can cool off more quickly than it heats up.

The rule should be to let the warmed water drain by gravity, no cold water permitted to push it along, at shower time. Some solar heaters use a toxic liquid through pipes partially in the sun, then back down through an insulated tank of potable water under household pressure. To use this water at the hot tap, cold water pushes it. We've got to do better, because our aim is to use no gas to heat water. Our goal is to use the sun alone, often meaning that we can't afford to spoil half the day's heated water with the cold water that pushes it along to the showerhead.

Turn off the cold water to a tank of hot water, and let it fall by gravity. You can shut the cold water off to a tank from the shower stall. I'll show you how to control a few things from the shower stall. It's not futuristic, but it works.

Some of you living in your fully-finished house at trib time might not be able to re-pipe easily inside the walls. One option is to build a room on a warm side of the house devoted to showering, no toilet, no sink, no tub. I'm going to design a hot water system here that makes the shower wall look like the dashboard of a pilot's cockpit. I'll be speaking as though the reader has some basic plumbing knowledge.

While it's not easy to build your own tanks to withstand normal water pressures, one can yet build to withstand some pressure. I'll show you how to put together a batch heater tank in a couple of chapters from here. For this chapter, imagine a batch tank on the roof, with 80 gallons all receiving sun. The tank is either fully sealed and fed with cold water by a low-pressure pump, or it's not sealed while fed by the regular household pressure. Inside the latter tank, there is an automatic shut-off valve like the one in a toilet tank. There are three water heaters (batch tanks) on the roof side-by side.

The heating process takes all day, but slow is how we like things in the country. You can take off your tie and suit here. But, here, put on this pilot's uniform. You should probably get out a pad of paper to begin a simplified drawing, adding to it, or redoing it, as I go along. Before you know it, you'll be infected with the inventor bug.

Imagine. The three tanks are tilted along the roof. The cold well water enters horizontally into the lower end of Tank 1. Water from Tank 1 is forced into Tank 2 with a pipe at their upper ends. We are still at ape-level intelligence here. Once this short pipe has penetrated into Tank 2, bring it downward with a 90-degree angle, and have the end of that pipe about a foot from the bottom. The object is to bring colder water in Tank 1 to the bottom of Tank 2 so that Tank 3 gets the latter's warmer waters before getting Tank 1's cooler waters. This is for small-use warm water during the day, not for showers in the evening. These short pipes can be eliminated by incorporating all three tanks into one container; see next chapter.

Yes, Tank 2 and 3 are connected with a pipe at their top ends. There is an outlet at the top far side of Tank 3 that goes to the hot pipe in the house. Throw me a banana, let's celebrate. But wait. We could use the three tanks as our entire system, as is, but that just wouldn't be complicated enough for our liking. We need a real struggle to prove that we are monumentally higher than the chimps.

Nothing is going to exit Tank 3 if it's equipped with an automatic shut-off valve. We must imagine these tanks under pressure, with the cold water pushing hot water out of Tank 3.

It's now 6 pm and the water is hot from a mainly sunny day. You can't brag about it because the sun has been responsible. You have four people who want showers, and on this night it's no problem; they all use the regular shower / tub faucet to mix cold with hot water the regular way, and water comes out the regular shower head on the wall, not powerfully, but nice and hot. By the time the last person is done, the water has gotten less than perfect, but that's okay...because you've got a big heart. Ahh, you're so swell, pops. Everyone warms up to you on this night.

The next day, lovely, white-puffy clouds roll in that wouldn't normally spoil your day, but at the end of it, the water in all three tanks is only lukewarm. No sooner does the cold pipe push a little water out that Tank 1 and 2 become ice boxes. Tank 3 doesn't stand a chance. There was mainly foot washing on this night; no one dared get under the showerhead after they heard the scream. When she appeared quivering out of the bathroom, her lips were deathly purple. What to do to solve? I have an idea. The back wall of the shower needs to become like a cockpit dashboard, and we're going to need an insulated storage tank. We can ask a gorilla to build the storage tank, but the dashboard is reserved for a higher power.

Instead of connecting Tank 3 to the hot pipe near the shower, let it go to the storage tank (which can be called the attic tank) with a pipe protected all around with whale blubber if possible. Whoever coined "blubber" did a very good job. It sounds like blubber looks. Instead of pushing roof water to the storage tank with the cold pipe, let it drain by gravity. Let the water leave tank 3 at its bottom. The attic tank's top needs to be as high as the roof tank's top.

We need another tank, this one a water-mixing tank which goes below the roof tanks so that the latter can drain into it by gravity. The very phrase, "water-mixing tank," should be your sign that we are embarking upon some hand-rubbing delight. What will you do with that scalding hot water from the sun? One way or the other, some of its heat will need to be wasted, either by letting it sit a little longer before use, or be adding cold water to it in the mixing tank. It will cool a little just by draining it into the empty mixing tank. But at least we're not wasting water heated by gas.

Draw on paper all the tanks at their proper levels. Leave a large blank area at the bottom half of the page for your cockpit dashboard. The only button you're not going to have there is one for auto-pilot, meaning it's going to take some careful consideration to make this thing fly once it's all done.

First, bring a cold water pipe (i.e. tapped into any cold water pipe in the house) to a wall of your shower. This is your dashboard. Put a manual shut-off valve (the kind you turn with your hand) on the pipe, and mount the valve tight to the framing on the shower wall, then pipe the other end of the valve to a hole at the lower end of Tank 1. Do the same with all three tanks, each having their own valve at the cockpit.

You're responsible for deciding pipe size in order to get more or less volume with its pros and cons. The larger this pipe, the longer one waits for it's cold water to drain before getting the hot. If the tanks are fully sealed, you need a one-way air valve to allow air into the top of the system, or the tanks won't drain. If a one-way air valve is impossible for you to get, bring a small pipe to the cockpit and use another valve to let air to the top of one tank. They will all drain with an air hole in only one.

Shut the cold pipe to the roof tank. Wonderful. We are ready for gravity to kick in to provide the shower. You can shut the tank's cold pipe, while not shutting down the rest of the house, by bringing the tank's cold pipe first to the cockpit. Put a valve there for the purpose. I would put this valve to the side, by itself, so that it doesn't confuse a pilot in the jungle of valves that you should have. Never turn a valve while standing under the water outlet at the shower. Test the water temperature first. You have the choice of the cooler waters in Tank 1, if they are warm enough, and keeping the hotter Tank 2 and 3 for showers later in the afternoon / evening if someone wants a shower then. It would be ideal if the cockpit showed the temperature in all three tanks. Can that be done?

To simplify the cockpit, you can have all three tanks drain simultaneously to one pipe and cockpit valve, but you don't get the choice of temperature differences between tanks.

As the system is described thus far, you don't get the choice of changing the temperature from any one tank. You've got to take the water at whatever heat it's at. But if you run all three pipes into the mixing tank, that's where you can have another cold pipe that turns on at the cockpit too, from a valve beside the first cold-pipe valve. Two cold-pipe valves beside one another makes sense of things to make it less confusing as to which valve does what. It may be better yet if you use one "transfer valve" (probably not cheap) that feeds cold to the water-mixer tank while simultaneously shutting the water to the roof tank...but you then get no choice of having them both on. I don't see any situation where you will want them both on simultaneously.

Now you can't run the roof-tank pipes first into the mixer tank, then to the cockpit. That won't work. Each tank pipe needs to come first to the cockpit valve, then up to the mixer tank, a good reason not to use larger pipe than necessary for the trip down and up again. But a larger pipe (only one needed) between mixer tank and showerhead is fine. Let's call this the showerhead pipe. .

If there is no valve in the showerhead pipe, you can't have the water in the mixer tank build up because it's going to come down as soon as it enters it. So, yes, yet another valve, this time in the showerhead pipe. This pipe is going to be at the ceiling, and so putting a valve up there makes sense. The mixer tank should be as near the showerhead as possible. You can now get the mixer tank at just the temperature you like it, best with a thermometer in the tank. You can forego a thermometer in one of the roof tanks with one in the mixer tank, especially if it gives an instant reading of the temperature. In would want one in at least one of the tanks to see how well the sun is doing on any particular day. It can help you decide when best to take showers at a glance.

There is a self-powered thermometer that hooks up to a faucet, but ideally, I'd want a wired one in the tank with a display at the shower. There are remote and wireless thermometers at Home Depot, but I don't know whether they can be submerged. Surf "wireless water thermometer" and hunt around.

There are going to be days when someone has used more hot water before shower time than other days. If no water is used before shower time, all three tanks will be at the same temperature. You have the option of forbidding (not with an iron fist, unless necessary) the use of hot water before shower time. Dishes can be washed in cold water, or pour some water into a bucket the night before to let stand at room temperature for tomorrow's dishes. Under this circumstance, you can use only one valve to drain all three tanks, but only if they are connected at their bottoms. You now have only one valve at the cockpit for the showerhead. It's your call on whether you want one valve versus three. In either case, there's only one roof-tank pipe going into the water mixer so that the difference between the two scenario's is just a couple of pipes and valves from the mixer tank.

For more work and cost, you can have three transfer valves (at the cockpit), for the three tank (water-supply) pipes, instead of regular valves, giving you the option of using any tank direct without going first to the mixer tank. This is useful when the day's sun barely gets the water warm enough for toleration, or for when it's warm enough only for a foot washing. There's less cooling of the water going direct to the shower head as opposed to going up to the mixer tank and back down again. All pipes coming down are insulated, right? Good idea. Chances are, you will have the valves up high, higher than the head, and if the mixer tank is on top of the shower's ceiling, just a foot or so from the valves, it's virtually pointless to have these three transfer valves.

I'm throwing you options, like when you're drowning in 30-foot waves and someone throws you a rope, you have the choice of grabbing it or not. In the same way, you have the option of pleasing your mates, or not. Drowning in the middle of a typhoon might be the better way to go than displeasing your mates on water temperature for showers, where they realize you could have avoided wrong water temperatures with just a few extra pipes. Better to do it from the start than when you realize later it could have been done better.

You may or may not need me to say this, but I will anyway for a time when you decide to take this chapter seriously. I realize it's just a pipe dream at this point. If you use three transfer valves, take all their one pipe each to the showerhead pipe. If you catch my drift, you can actually do a little water mixing right there in the showerhead pipe by opening two valves at once, if for example one tank has warmer water than another. This is useful if you have no choice but to have the mixer tank not near to the shower.

So, you now have two valves per tank in the one transfer valve per tank. All three valves have the temperature display of its respective tank beside it. If you feel that transfer valves are too costly, you can instead use three additional valves in addition to the first three that send water to the mixer tank. The mixer tank's advantage is that you get to mix the water for an entire shower before turning on the supply to your head. With the other three valves, you get the temperature on your head immediately, even if it's the wrong temperature mix. You really don't want kids operating this thing unless they are firmly told to test all water temperature before it comes down. If the water in the showerhead doesn't spray around, it will be fast to get out of the way of too-hot water. If the shower head is more to one end of the tub or shower stall, rather than in the middle, it will be safer for getting out of the way. You might even decide to have the showerhead valve lower down and reachable from two feet over from the showerhead.

As much as we much like handles looking like miniature racing-boat steering wheels, I would suggest the lever-type handle that quickly shows whether it's in the off or on position, and quickly shuts off.

As you can tell already, you're going to need to tidy up your drawing like an expert draftsman. Where exactly you locate all the valves on the cockpit dash is up to your fancy, something you can figure out later; for now, as I've never claimed to be infallible, just draw it to assure that what I'm saying will actually work. I wouldn't read any further if I were you unless I was looking at a drawing that looked like it could work. After you're sure it will work, you can make changes as you like.

If you must have pressure at the shower head, you can use a pressure vessel pump, good for taking waters out of any unsealed container (including rain barrels), and applying pressure for the taps without having a water-pressure tank between the pump and taps. However, an owner of a pump shop that I just called says that these are low-volume pumps good on the order of 1 gallon per minute, which is not much of a shower spray at all (see website below). Maybe there's better ones. You now need an electrical switch at the cockpit to start this motor, which can take water from the mixer tank.
http://waterplex.com.au/category/accessories/rainwater-tank-water-pumps/rainwater-tank-water-pumps/

As you won't be holding a job in the trib, you can at cooler times of the year skip more than one day from the shower. I'm not speaking for the women, as they don't like anything that sounds like that. You speak to them. I'm scared. Just tell them John has good news: a little-bitty water daily to get the areas between toes, and a wipe of private parts, and you're good to go. Underarms are easy to do with the shirt still on. It's no big deal if on cloudy days you haven't got sun-heated water.

I had more than enough money to build my house when starting out, but the house ended up only half done after a few years, without a water heater even. My bad luck is good for you. They sent me a gas heater instead of propane, which wasn't realized until after I fully installed it (they look exactly the same). Some time went by before it was taken back, by which time money was running low, causing me to go without a water heater. I wasn't planning on it, I assure you. So I know how to take a shower with about a gallon and a half, heated on the stove. It's completely fine, so long as the bathroom, or shower stall, is warm.

Life with some humiliation and little means is good; keeps us out of the wrong circles. Having both may make the world go by rather than making the world turn, but if money makes the world go round, maybe God would rather have the world go by on us. Yes, I think that's what Jesus meant.

The luxury of my propane at a stove burner heated a casserole container of water, and that's all that's been needed for one "shower." There's usually been an inch or more at the bottom of the container left over for the final great pour over the head. You never knew a few glasses of hot water could be so nice. Except for living in a normal house in winters, I've been doing this water skimping for years, as if maybe God wanted me to be a pioneer for informing you.

There was even an argument with the electricity people (regarding their high price of about $12,000 to get it all in) so that they betrayed me at the last moment, after I was moved into the property (no house, no nothing) with only a trailer, forcing me to get solar electricity instead. How did this all happen? Therefore, I've become an informant by now to inform you on that too.

I've learned to do both feet (on the edge of the tub) with about one small margarine container of water, which is what's used to scoop warm water from the casserole container. Just slip feet into rubber sandals to let air dry; keeps the towels going longer before they need a wash, and who wants foot residue on a face towel, anyway. Fold and dip (only once) paper towels into the pan water, do what you've got to do, and you'll feel clean. Hair can miss a day, even two or three before it feels like invisible things are crawling in it. The rest of the body not having folds or dark places doesn't need a wipe; it can wait until the next shower. I'm telling you this to inform that a half pan 2" deep and 12" round of body-temperature water is more than sufficient for your needs. You've gotta shake some sense into your wife and tell her, it's okay, it really is, we're going to make it.

One roof tank will do a small happy army by a wipe bath. They'll be happy for any warm water at all. So that's what we can expect as a worse-case scenario in this regard, providing that your area does not get clouds six days a week for months. There are rain- and snow-trough areas best to be avoided if you want solar energy. There is plenty of sun in the middle United States that is very low on liberals, and very high on Bible-appreciating folks. Do you think this may be by Design as the Time approaches?

When your wood stove is used to heat your home for a burn of at least half a day, you can ask less of the solar heater...because it's not going to give you more even if you beg. For those days when the air is cold outside while it's not yet warm enough for the wood stove, a pan of water or pail sitting inside a sunny window will be warm enough for the dastardly sponge bath.

I can't stress this need enough for a large supply of paper towels / toilet paper; if you end up in a situation where showers must be severely rationed / canceled for long periods, your crotch could develop some nasty things. You'll all become crotch scratchers. Everyone will know what you're doing when you suddenly leave the lunch table for a shorter time in the bathroom than it takes to use the toilet. They're not going to ask whether you washed your hands, but they won't ask you to pass the bread either. Fungus-killing pastes are highly recommended for trib survival, but you can get ten rolls of paper towels for the price of one tube of fungus fighter. I've read that hydrogen peroxide can help with athlete's foot, but don't know how reliable that advise is.

A mouse-free attic would be a great place to stock large-volume items like paper towels. Creating a larger opening into the attic to make the trips more comfortable is an option. You can purchase fold-down ladders made specifically for climbing into attic holes, or just do the old-fashioned ladder.

Who really wants a sealed tank if it's not necessary? Well, if you built a sealed tank before the trib, you can put its water through your gas heater, and by the time the trib arrives you may have paid for it on saved gas. If you outfit it with all the outlets needed for the cockpit situation, and just cap the pipes coming out, you'll be able to use the tank fast for the trib should it arrive in your lifetime.

There is a way to take the chill off of Tank 1 for small-usage water before shower time. You have a small, pressurized tank with a pipe to Tank 1. In this way, this other small tank (in the attic sounds good) gets warmed by air overnight. Or even if cold water enters it by day in a vastly-hot attic, it gets a lot of chill removed. But before the waters of this small tank get to Tank 1, they go to the cockpit so that your people have the choice of turning it off. I'm not adding another cold pipe in this situation. This is your main cold pipe now. You can leave it on, of shut it off. If it's left on, Tank 1 usually gets warmer water than if the cold pipe were direct to it. It's a win-win at the small cost of a small uninsulated tank (you want heat to get to it, don't insulate it).

It's not very likely that the automatic shut-off valve will fail to shut water, for they last more than ten years in toilet tanks without failing to shut water. Toilets may often over-run, but not due to the failure of the shut-off mechanism. Toilets over-run when the setting of the mechanism isn't set properly. For protection beyond their reliability, you can install a flow sensor (see webpage below) to shut off the water supply automatically should the shut-off valve cause an overflow to the sensor. The company selling these sensors also sell electric actuators for opening water valves from a distance (streamlines your cockpit by removing the valve handles, but more costly).
http://www.irritrol.com/sensors/sensor_flowsensors.html

You build the roof tanks to take some water pressures, and run down the air hole to each tank with one pipe to the cockpit, thus being able to open/shut air holes at will. If you like, in case the tank leaks a little under pressure, install the automatic shut-off valve anyway, but have a second cold pipe going in, which will fill the tank with pressure (won't harm the automatic shut-off) for times when there is abundant roof water and you want a pressure shower for a change. Shut the cold pipe after the shower to cancel the leaking.

On a day with lots of cloud or cold air. Step one: take off your clothes, get into the shower, and block the pressurized cold water from entering the solar system. Step two, stop shivering, and open the air holes (these valves would be placed well side-by-side). Step three, pray the water is at least warm, and open the valve from the warmest Tank 3, or, if you're the man of the house, use the coldest Tank 1. Sorry, pops, but you're the man. Be the man. You shouldn't be the first one in there, anyway, but on this occasion, we need you there to teach us how to operate the controls, and to learn what yet needs to be done to perfect the system. Don't forget to sing loud so everyone in the house can hear you. That way, they'll think you're having a great time. You wouldn't want them to find out, until they're committed in the shower too, that the water tonight is like ice.

Solution as best it can be had: don't get in under the shower to wet the entire body yet. Put the stopper in at the shower's/tub's floor drain to retain warm water on the floor. The cold air in there is much from the floor. I know that you'll figure these things out when you get there, but just to give you a heads-up on what to expect. Get some hot water to warm up the floor by washing the legs and feet first, as they don't feel nearly as cold as a wet upper body. Rinse the legs. How? Fill a bucket partially at the shower head. A small container then allows the showeree to scoop water as needed for rinsing legs, and by that time the floor starts to warm up quite a bit, after you've washed up completely (upper and lower), dump what's left in the bucket over the head and things get better fast. It's then time for a quick towel that you grab from inside the shower; dry yourself in there, because the north-pole chill is just outside. I've done this many-a-times.

Actually, if people take showers back to back, the first one in gets the worst cold. If you get out of there quick, the floor and walls will be warmer for the second person.

Problem: what if the water is too cold as it cascades on your head and body? You'll live. What if it's scalding hot? Serious problem. Doing the hand test at the shower head won't be good enough. It doesn't magically get rid of scalding water. You will recognize how truly human you are. But after the dreadful days have passed, the sun has come back. And you'll be stronger, because you're going to need it.

Aaaaah-yeeeaaahhh-yeeah-yeeah-yeeeaaaaahhh. That's the word Tarzan invented when he was wildly successful pleasing Jane in her dastardly trials. You can be a problem solver, or you can be a problem. The vine can be used for jungle transportation, or it can be the entanglement. The sound of too-hot water on the head can be much like that word above.

The chimp says that we should label all the valve handles. For example, we could call one, "Water-Mixer to Shower," or another, "Tank 2 to Water-Mixer." It gets a lot less complicated that way. All valves can be separated into groups; three here, three there, two over here, one there, and two more smack dab right here. It looks like a good problem solver, no entanglements so long as we know how to read. Each valve is like an off/on electrical switch, but more like a dimmer switch because water volume can be chosen anywhere between off and fully on.

There is also the water pipe from the insulated storage tank. We could do the same for this pipe as is done to the roof tank pipe(s), allowing two destination options using two cockpit valves, one destination to the water-mixing tank and the other direct to the shower head. You may decide that this is overkill, that one pipe from the mixer tank is sufficient; just let any tank drain first to the mixer tank before it gets to the shower. For those times when the water is borderline tolerable, the mixer tank cools the water a little, making direct water appreciated.

The reason that you should opt for one pipe each to the shower from all roof tanks is that it gives the option of using the colder tank first. If you have only one pipe coming to the shower for all three tanks (they can all be connected at their bottoms or tops), you'll probably put it at the hottest Tank 3. By the time that the warmest waters are used, the coolest may be too cool. But if you have one pipe each per tank, the coolest water can be used first while still of a decent temperature, and the warmer tanks will, hopefully, be decent when others get around to the shower.

It will be helpful to use roof-tank water direct on certain days sunny enough so that storage-tank waters (too cool for showers), poured on a previous the night, won't need to be wasted (thrown out) in order to protect the borderline-decent water in the roof tanks. It's helpful not to throw out storage-tank water, no matter how cold, because you can get some of it into the sun. It's cold, but not as cold as putting ground water (cold pipe) into the roof tank.

Consider a day where water of about 95 degrees ends up in the storage tank by shower time, and 85 degrees is achieved with a second load of water in the roof tanks. The two tanks can be mixed for a not-bad 90 degrees. You can let the waters mix in the showerhead pipe by allowing both tanks to drain at the same time, or you can let both drain first in a mixing tank.

Let's give the captain a real challenge. For example, it's July 15 after three days of clouds (passengers feel bugs in their hair), and the tanks are almost about to boil. The sweltering attic has heated the storage tank to skin temperature. The passengers are clamoring to have their showers, but, combined, they want more water than what's in the storage tank. The pilot's at the cockpit not sure which switch to pull to ride out this emergency? Turbulent flight has given way to dire thoughts of mutiny. The captain's looking intently into the dash, and all around. There are myriads of handles, so confusing. No wait, not that one. Maybe this one. No, wait, there, what...he's looking around some more. The monkey screams: "the blue handled valve!"

"There is no blue-handled shut-off valve," he cries back.

Get one, and make your roof-tank valves red. If you opt for both direct (red handles) and mixer-tank waters (red handles), put a purple dot on the mixer-tank valves. A blue handle gets cold-pipe water to the mixing tank for when roof water is too hot.

"Captain, with all due respect only because this is your house, it's the monkey that supposed to make lips of an embarrassing shape and scratch the forehead, not you. If it makes you feel better, I'll pass on some good advise from Tarzan: don't be dismayed with anything that looks like a jungle. Have a lot of vines as options to swing things better." In other words, don't be afraid of more valves in the cockpit. Valves and pipes are cheap, you won't regret the options.

On some days when the storage tank is filled with previous-night waters, you have the option of not pouring any roof water into them on a decent-sunny day. If perchance the roof water gets to hot, you can use the storage-tank water to cool it.

With a temperature display above all red valves, it's cruising time ...unless there's only two gallons left. There's one kind of scream for too-hot water, another for too-cold, and yet another for being in the middle of a sudsy shampoo without water to rinse it. The latter one sounds angry, almost like a curse word. There has got to be a low-water indicator...more than you may realize. For example, you would locate thermometers at the lower end of each tank because you don't want water level to drop below the thermometer. But what happens when there is no water in a tank, yet the thermometer reads a high temperature. That can really put a monkey wrench into your engine. You start mixing waters according to the temperature displays, yet one of the tanks doesn't have water, which you don't know, and so the water comes from the mixing tank either too cold or scalding hot.

Or, a tank has a few gallons but runs out midway into the shower, with someone vulnerable under the showerhead. You therefore have got to know when a tank is low if you opt for direct water (forego the mixing tank). The alternative is to always use the mixing tank; shut off all water to it before the shower, and then open the pipe from the mixing tank. It's safer.

There are sensors that control water valves. If there is a valve that shuts off when too hot, that's an important item for the showerhead pipe. If they exist, why haven't I seen one at Home Depot?

A thermometer in a roof tank should be blocked to direct sunlight. It's invaluable because it can inform you when to drain water to the storage tank if there's time left in the day to heat another load of roof water. Can you think of a way to fill only a half tank of water if there's not enough time left to heat the full tank?

Chimpanzia has got another word of wisdom: if we're going to swing the vines, we need enough trees as options for a soft landing, or we'll swing back and hit the one we took off from. She says Tarzan used to do that a lot when he first started. She says we need to know where we're going, and that we're going to be able to get there once we take off. There needs to be some instrument telling how much water is in the tanks, just like the kind in your cars that tell how much gas you've got. Like maybe some water pressure sensors on electrical wires to gauges in the cockpit.

With the cold-pipe valve, you can determine how much to fill the roof tank at any time, if you have a gauge that tells how deep the water is. If it doesn't look like the day, or the rest-of-the-day, will heat a full tank, you can fill it only half way. It's a super option. There will be shorter showers that way, but warmer. Ask your passengers which they prefer, and they will say: get the depth gauges.

Just think, the more complicated this gets, the more time you'll spend training the passengers to do it acceptably on their own, very nice especially if you were single and all the gals were airline stewardesses. But, lets get real, you stand as much chance being bashed on the head by a purse as you do receiving one of them lovely smiles.

Captain, I can really see the options expanding wildly, and we can be in firm control of the waters coming down, knowing exactly what's coming down, just like air-flight controllers. Just think of how much ooh-and-awe you'll be getting from very satisfied passengers if you bring everything down just right. To make for an even better splash, we've got to have the water coming down on the head and shoulders better than just out the end of an open pipe. Let the waters spread out a little. Be inventive. For example, get your soldering kit, a few copper elbows, and turn that open end into four or five open ends, each a few inches from one another. You can't have a softer landing than that.

I will explain this cockpit again in two chapters from here, at which time you will have a fresh start for better (less-confused) understanding.

Make sure the pipes are positioned to drain naturally before the winter freeze, with no water trapped. Otherwise, use some form of an air blower (besides your mouth, preferably) to blow water out.

BY THE WAY, if you don't know about starting a fire, or heating water, using a giant water-based "magnifying glass," see the video below. Just build it as you see it, and put a lid on with hinges to keep sun and rain off of it. You can cook with this, I suppose, or even pass pipes through to heat water for a couple of hours at midday. The kindling temperature of wood is much higher than water's boiling point:
https://www.youtube.com/watch?v=eeSyHgO5fmQ