Holding Tank Capacity?

[Doug1968]

Fellows,

I am working on a layout for my holding tanks in my 102A3. I would like to have enough storage to support two people living in the bus in the boondocks for 16 days. This would include fresh water.

In measuring the bay it seems as though the best usage of the space would be to have the tank designed to be about as tall as the bay. This would be the most efficient use of the space it seems. I realize that there will be a need at the top for the fittings.

This is my first RV and I have no idea how large of tanks it would take to last the 16 days? Another thought that came to me when measuring the bay area was how low the bay floor is to the ground. Would I have problems with the tank draining if the tank was sitting directly on the bay floor?

I do not plan on having a dishwasher or washing machine and I would like to think that we could learn to shower every other day to save water.

I would like to hear from the group your thoughts on the tanks sizes.

Thanks,

Doug

[luvrbus]

Doug, figure on 10 gals a day and that is with a very short shower I have 160 gal fresh water tank and it will last us 15 to 16 day taking short showers every day.
My drain comes out under my bay and some time it is a problem dumping hind sight I would have left mine floor level in the bay but I thought at the time that would create a mess in the bay but it works good for my friends.
One good thing about under the bay when you find a grated dump you don't need hoses. 
You will get different answers here on tanks and drains everyone does it different ways, but I have been around some at Quartzsite that use the 2 gals a day not nice LOL   


good luck

[bobsw]

We have 200 gal fresh  and 100 each of gray and black. We have the shower plumbed into the black tank which helps by adding liquid to the black and saves on space in the gray. We spend the winter boondocking at quartzsite AZ We go dump and fill with water about every three weeks. we do use a dishwasher I have found that the wife uses a lot less water with the dishwasher than washing the dishes by hand every day. She stores the dirty dishes in the dishwasher until she has a full load then the dishwasher only uses about 5 gals of water.If she were to wash every day she uses a lot more water.

[Sean]

We have 135 gallons of fresh water for washing, a separate 40 gallons of water for drinking, and a 135 gallon gray water tank.

With that setup we can go 14-16 days, but we always take "navy" showers, often shower every 36 or 48 hours instead of 24, and have a special set of valves that allow us to get "instant" hot water without wasting a drop waiting for the shower or sink to get hot.

Our black tank situation is a bit weird, since our toilet is two bays behind where the tank is, and we have to use an air-flush model that requires half a gallon per flush.  Most direct-drop RV toilets use much less water.  We have a 65 gallon black tank, and even then it will not go the full two weeks unless we conserve however we can, which means peeing in the woods (or desert) whenever we can, using restrooms at the office if we are on a job, and other strategies that are best not discussed in polite company.

If you can be ultra-conservative, you can get by with ~5 gallons per person per day.  Your gray tank should be at least as large as your fresh tank.  With an RV-style toilet, a gallon or two per person per day should be sufficient.  Remember, fresh water hose bibs are much easier to come by than dump stations, so err on the larger side for the waste tanks.

-Sean
http://OurOdyssey.BlogSpot.com

[JohnEd]

You will never have a problem finding a spot to dump the gray water.  The black is a problem.  I think 50 gal is min for black and a weeks worth of capacity for the grey.  You can run the grey thru a 50 ft garden hose to a storm drain or a ditch or just down the hill.  I Kalifornia they used to give tax credits to folks that plumbed their shower and sink into their garden or front yard underground.  Technically....it is sewage when that is what they want to call it.

Give some thought to this tank config.  The fresh is a oblong tank 18 inches high and as wide and long as you want to make it with capacity as your guide.  The tank lays flat on the floor of the bay on top of 2 to 4 inches of foam insulation board.  On top of this tank site two tanks that form trapezoids and when nested on top of the fresh tank they are the same dimension.  One tank sits directly below the toilet and the other....doesn't.  If you heat the water in the fresh tank it will heat the other two tanks and there is a really easy way to heat your fresh up to 50 or 60 degrees.  Obviously there is some limited framing.

A serious advantage of this config is that the area devoted to tanks is a cube, overall.  I think you want the tank final config to be as high as the bay will allow and your width will determine the overall capacity.

Sean mentions not wasting any water getting warm water to your shower or sink.  That is done by plumbing a warm water return to the fresh tank that is controlled by a push button valve mtd near the sink or shower.  Press the button for a few seconds and you will run hot water right up to the hot valve.  That hot water going back to the fresh tank can be as much as you like and in winter the capacity of the HW heater, dumped every so often, will keep your wet bay from freezing.  Neat huh?  Multi use systems and redundancy of critical systems!!!!!!!

HTH,

John

[John316]

Doug,

Interesting that you should ask this. We are going through this right now. Here are a couple of things to consider.

If you go custom tanks, you will want to consider a couple of things. If your tanks go all of the way to the ceiling of the bay, what about vents, and where do you tie you drains into (I know that you know this, but it takes more space that you want )? We thought that we had a lot of that figured out, but we would have been in big trouble if we wouldn't have been able to change our tank configuration. Also, depending on the setup, you will need to carefully decide where you want your dumps too be. Also, if you custom order your tanks (we did for three of ours), 24" seems to be the magic number. That is the size of their sheet of plastic, and that is the cheapest way to make them, if you can stay away from using extra sheets.

We have 120 of black, and 220 of gray (one black tank, and two gray). Right now, we only have 80 fresh. We are going to put another custom tank in the back bedroom, but we haven't ordered that yet. We figured, for this trip, we can fill up with fresh just about anywhere. Eventually we will have matching fresh, to the gray and black.

I will be able to help with more info, when we are done.

God bless,

John

[Singing Land Cruiser]

Hello All, I sure you already have one of these, but if not this could help; http://www.watertanks.com/calc.asp  All the Best,M&C

[blue_goose]

I don't know where he got his tanks, but they are built for the 102A3 to fit under the hump in the bay.  My son is on the net and may see this and chime in, if he doesn't and you want to find out where he got the tanks send me a PM.  I don't think he paid a lot for the ones that he got and they sure went into the bays nice using all the space.
Jack

[Jerry32]

When i laid mine out I wanted to have my tanks up high in the bay so I hung them as high as they would go. This gives me a drain that is high enough to be contained within the bay and when at an RV park I can send a hose out to the sewer conection through a hole in the floor of the bay. I ran the drains together so anly one outlet and two valves. I then mounted the water tank underneath the waste tanks setting on the floor of the bay. I travel in sub freezing weather and use a thermostatic controlled heater in the bay to keep things from freezing Jerry

[TomC]

I have 130gal fresh, 85gal gray, 45 gal black.  We can go (wife and I) a week on that water with both showering everyday and doing dishes.  With practice, we probably could stretch it to 10 days.  The gray does fill up first.  One of the best features I put on is a curb side open drain for the gray tank.  Just park over a drain and let er go!  The 45 gal black can easily go a week.  
On my truck conversions, I'm increasing to 175gal fresh, 110gal gray and 75gal black.  I will also plumb the gray into the black with a T to also be able to empty the gray separately and with the curb drain also.
One of the best ways to conserve water is to put in warm up valves, like Sean said.  I'm just doing a simple extra valve on the shower and kitchen sink where I can run the hot water with the pipe leading back to the water tank-so the pipes can warm up without wasting close to a minute of water at the shower while it warms up.  Good Luck, TomC

[MattC]

I took the lazy way out.  I picked up four tanks from Bontagners that are ~ 12" x 24" x 72", it comes out about 80 gal each.  I set aside two for fresh water, one black and one grey.  However the grey has an overflow into the black tank.  I chose to keep them separate to provide a bit of flexibility as well as being able to purge the dump hose.

They fit nicely in my rear bay with a bit of angle iron and 1/2" plywood for bracing.  Now I have to get the spin fittings attached.

[Dreamscape]

Matt,

Do you have any pictures to share?

Paul

[84dime]

Not to steal this thread but what are dis-advantages to having just one black/grey tank? and what about aluminum?

[JohnEd]

Joshua,

There are some that combine the gray and black and it works for them.  I think those people dry camp less than most, if, at all.

If they are separate, then you can dump the grey almost anywhere...storm drain, in the ditch or down the hill from your camp with a 50 foot hose.  It gives you alternatives.  The black fills slower so you can go longer between visits to a dump station.

Alu rots with come of the chems and sewage we put in the tanks.  The hot setup is stainless steel  holding tanks...three of them.  I suspect that SS was an upgrade option when those Puppies were built.  I have only seen them in Hi Line Pre's but I have led a sheltered life so that doesn't really mean all that much.

John

[Melbo]

We have 165 of fresh and 65 of black and 100 of grey and we can go for at least 3days with no problem.

If we are conservative I am sure we could go 4 days.

We live well when we are in the coach.

The combination of 330 gallons just about fills up one bay of an MCI 8

Leaves just enough room for the pumps hoses and drain valves.

If you want to have more look under your bed and think about putting the pumps and valves in the next bay over.

The bays are just so big and only so much will fit.  You could probably put 400 gallons in a bay but not with all the plumbing.

Careful planning will be your friend. --- My tanks were custom built for my bays.

Melbo