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RV Holding Tank Tips that will save you money and time.
Typical RV Service Center.
You need to make your Holding Tanks assets rather than liabilities
Every RV owner quickly finds out that managing the Holding Tanks in their RV is one of their most important tasks if they want to have an enjoyable camping trip.
This part of the camping and traveling experience, in an RV, can be the most unpleasant, or at least the most boring, yet necessary, things that we all need to understand and know everything possible about.
Follow these tips and make your holding tanks efficient parts of your RV rather than problem areas.
Holding Tank Size and Content Weight
Over the years, I have owned 6 Motorhomes, two trailer campers and a fifth-wheel camper. Each of these, just like yours, had three holding tanks that had to be managed; a Fresh Water Tank, a Gray Water Tank and a Black Water Tank..
Even though each manufacturer uses different size holding tanks in their RV’s, typically each is designed to hold the water and waste needs of a pair of people for a week or so, depending on the size of the RV and what they consider average water consumption and usage.
You see, water is heavy, in fact one gallon of water weighs around 8.34 pounds, For conversions of this number click here; Weight of Water.
The Fresh Water Tank
All of the RV’s we have owned in the past, had a Fresh Water holding tank.
This tank is the traveling camper’s source of; fresh water for drinking, clean water for washing dishes, water for the sinks when brushing your teeth, shaving, washing your hands etcetera, even for your Ice Maker in your Fridge.
It is also the source of fresh water for your shower and it provides a small amount of water to clean out your toilet with each flush.
Because of these needs, the Fresh Water Tank is usually the largest of your holding tanks.
For instance, in my 35-foot Fleetwood Bounder, my fresh water tank is capable of holding up to 85 gallons of water.
It only takes a quick calculation to realize that my 85 gallon Fresh Water tank can be holding over 700 pounds of water weight or from my perspective excess weight that burns extra gas when it is hauled down the road.
So, the frugal RV owner will try to manage this eater level, not only in the campsite but also when preparing to it the road.
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The Gray Water Holding Tank
The second holding tank in your RV, by size, is the Gray Water holding tank.
This tank is in your RV to collect and hold the drainage from three sources in your RV; the kitchen sink, the bathroom sink as well as for your shower/tub when you take a bath.
This “Gray Water” is dirty, but it is dirty with soaps, maybe a few food bits and just plain dirt. But this content isn't considered to be "sewage waste", so it can often handled a little differently from the contents of your Black Water tank.
The Gray Water tank in my Bounder is capable of holding up to 58 gallons of this "non-sewage" waste water.
Again, making a quick calculation, and assuming that the Gray Water weighs the same as the fresh water, will show you that this tank of Gray Water can weigh up to 484 pounds. Again, this is not weight that you want to be hauling around in your RV.
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The Black Water Tank
The third and really the most important holding tank for a camper is the Black Water Tank.
Many people just don't want to talk about sewage waste, but in an RV, and actually in everyones life we, as humans generate sewage.
This holding tank on my RV conveniently holds the waste from my toilet. And, OK, you’re right, no one wants to deal with sewage, but as traveling campers who use our RV regularly, we need to manage this tank properly.
At home your sewage goes down a pipe and disappears somewhere very conveniently across town where it is processed and disposed of properly.
But in the real world, specifically the world of camping, sewage requires some special handling. As a camper, you are more aware than most people with having to handle such a byproduct of life, so you already know that do it properly and cleanly every time.
The Black Water Tank in my Bounder can hold up to 42 gallons of sewage waste. Once again, using the standard of 8 pounds per gallon, a full Waste Water tank can weigh as much as 350 pounds, or more.
Actually, considering the fact that there is a significant amount of solid waste in your tank, from using toilet paper and the fact that “Poop” is a solid, this number can be as much as another 50 pounds higher than if the tank held only water.
One thing you want to do with your Black Water Tank is to add the appropriate chemicals so that your sewage waste starts to break down quickly and efficiently.
You see every septic tank grows its own bacteria and breaks down sewage, but at a slower pace than you will desire, considering you will be dumping your tanks possibly as often as weekly.
And almost as important, these chemicals will dramatically reduce the potential for sewage odors to rise up from the tank and into your RV cabin.
You can purchase these chemicals in most RV parts stores or you can order them online, if necessary.
Liquid Weight and being On the Road
Add the three numbers I have shown above together and you will get a total of (700 + 484 + 350) or 1530 pounds (or more) of liquid that can be in the holding tanks alone, in your RV.
Now, if you’re like me, you already cry every time you fill up the fuel tank in your RV. Driving, or towing, a small house down the road is not a cheap proposition and fuel costs are a major concern when you are traveling any distance with your RV.
The typical RV does not get good fuel economy anyway, just from the total weight of the RV itself and all of its accessories and equipment that are part of the RV itself.
So, regardless of whether you get as low as 7-mpg (which is very typical with most older RVs) or maybe 10-mpg or 12-mpg (that you might get with a newer, smaller one), you are always looking for ways to make sure your RV is giving you the lowest fuel costs possible.
Liquid Weight Management Tips
You can see from these numbers that if you minimize this water and waste water weight, which can be as high as 1530 pounds, when you are on the road, you can have some effect on your RV fuel economy.
The following are some sound and useful tips on managing your holding tank contents, for the concerned RV owner to know and use when traveling in their RV.
Of course, you want to have Fresh Water available in your RV at all times, but there are some smart things you can do that can save you money while on the road and camping.
If you are going to be rough camping, in a state park or in the woods and there are no connections to fresh water at your intended campsite, then you should, of course, travel to your campsite with a full tank of Fresh Water.
But, if you are only going to be traveling with maybe one overnight stay at a Rest Area or a Walmart or some other rough site with no connections, and will then be staying in campsite with full hookup, you have another option.
You can just fill your fresh water tank with maybe 8 or 12 gallons of fresh water. This will typically give you enough water for flushing your toilet, washing dishes, cooking and other tasks on an overnight stay. And you will to be traveling with the excess water weight of over 400 pounds of excess fresh water.
First of all, do not leave your holding tanks full of waste, even gray water waste, while it is in storage.
Even though Gray Water waste does not carry the levels of active bacteria in Black Water Waste, or have a very high level of solids content, you do not want these solids to congeal and solidify in the bottom of your tank, thus reducing your storage capability.
Especially, you should not travel with a lot of extra weight from waste water that can be dumped before you hit the road on a trip.
And, if you are going to be rough camping you want this waste tank totally empty.
The rules for Gray Water management while traveling is pretty much the same as with Gray Water, with a few exceptions.
First of all, never leave Black Water waste in your holding tank when you are going to store the RV for any length of time.
As mentioned, there is quite a bit if solid waste in every tank and when this gets a chance to solidify. It can be a real task to soak into the resultant solid mass and eventually break it down to the point it can be flushed from the tank.
Shake it down the Road
In fact, because of this potential buildup of solid waste, I have a thing that I do on every trip. I always put at least 10 to 15 gallons of water into my Black Water tank before I hit the road.
This water will “slosh” around in the tank as I drive down the road, and in my mind, it is beating against any solids that may be in my tank. And, hopefully, it will break these solids down for me insuring that I keep my Black Water tank as empty of such buildup as possible.
Prep Empty Tank with Water
Always prep your Black Water tank with at least 2-3 gallons of water after it is emptied. You do this for two reasons; one is that you will also add chemicals into your tanks with this water which helps prevent odors, and two because these diluted chemicals will help the necessary bacteria start that breaks down sewage whole it is in your tank.
Holding Tanks in summary
So, the smart RV owner will manage their holding tanks and their contents carefully, not just to save a buck, but so that everyone in the camper can have a much more pleasant trip without worrying about the world of water and waste.
And as you can see from this article, when you look at the weight of a gallon of water, and then at the size of the holding tanks in your RV, you want to come up with a plan that allows you to travel comfortable in your RV, but also do it with a minimal level of extra liquids in your Holding Tanks.
Use the Campground Facilities
Probably the most important thing what my wife and I do when we are camping is utilize the facilities of the campground itself, as much as possible.
Of course we use the showers in the campground bathhouse instead of the one in our camper. They are only a short walkaway and they are invariably clean, so why not?
Normally, during the day, and in good weather, we will both "Poop" in the bathhouse also. Again, its a matter of convenience and reducing the need to dump our tanks as much as possible.
A little pre-thought can save you from dumping too often and from from hauling too much excess liquids as you travel.
by Don Bobbitt, June, 2015
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© 2015 Don Bobbitt