Black Tank Maintenance
By: Bruce Cavanaugh
This message contains sensitive material and parental discussion is advised:):)
Six years of black tank living experience have taught me the following.
After almost two years of living in my RV I have a problem, seemed as my pipe from my toilet to black
tank was clogged as my tank sensor says the tank is empty.
First you must picture your black tank, they are long and wide but not very deep maybe five inches
deep. Then your pipe coming straight down from your toilet and goes into your black tank. Typically this
usually just goes into the black tank about one or two inches past the top of the black tank.
So as you can picture straight down comes the sewage and deposits on the bottom of your black tank
usually right below the pipe coming down from your toilet into your black tank.
Now if you are not moving and have little water in your black tank it begins to pile up. Even if you have
water in your tank it usually is hard to get it to distribute evenly through your black tank but usually
begins to pile up under the dump pipe.
In a new tank the solids spread out forming a base of about one inch thick after sitting the bacteria takes
over and they become like clay. Then as you use it the solids build up like a pyramid right below the pipe
opening that comes down from the toilet and can back up into the pipe. This can become very hard to
remove and eventually be impossible to get out and you must replace your tank.
So it is very important from the start of getting your new Forest River RV to make sure you use some
type of black tank chemicals now and then but most of all flush your tank out good each time and make
sure it is empty then add some chemicals and water, do not let sit stored with a dry tank.
1.Forget your tank sensor they are worthless after about a month of use and can read empty when full.
However I have found if I do the following my sensors usually work ok all the time.
2.Always keep about one inch of water in the bottom of your black tank just run your toilet for awhile and
it will add water after awhile, you will get how long to run it. I usually run mine about two minutes after I
empty my black tank. NEVER, NEVER, EVER let your black tank valve open all the time, only when you
dump.
3.Invest in a clear tank coupler that attachés to the outside drainpipe so you can actually see what is
coming out of your tank. I recommend the Flush King from camping world. You can see what is coming
out and it has a water hose attachment and shut off valve. With this you can back flush your tank and
also see what is actually coming out when dumping. The neat thing about it is there is a close off valve
after where your water hose attachés so the water cannot drain and it will backup into the tank. By
closing your black factory black tank valve and letting your gray tank open you can back flush that tank
also. You can back flush all your tanks this way by closing all the tank valves and just letting the one
open you wish to back flush.
**CAUTION THOUGH** do not let your water run to long if your tank fills up completely and backs up you
will have a MESS! Experiment the first time so you learn how long you can let it run. NEVER, NEVER,
NEVER get distracted when doing this or you will overflow your tank!
4. If you store your trailer never let the black tank empty always fill it up with some water and chemicals.
If you are in a freezing area just add some RV antifreeze also. If you let it sit empty the bacteria will build
up on the tank walls and any solids on the tank bottom will become like concrete.
5.If you think your tank has some build up invest in a RV Flexible Swivel Stik, this will rotary clean your
tank using water pressure.
6.When you move your RV always make sure you fill your black tank half with water an add a double
dose of tank chemicals and two cups of chlorine bleach. This is practically the only time you can get
your tank clean. Because when you are driving down the road all the bumps and turns really slosh the
water around in the tank and get it good and clean. The chlorine bleach will help clean your tank
sensors by killing all that bacteria that has stuck to them. One you reach your destination empty and
flush your tank well.
After moving and then dumping as explained above my tank sensor usually always then work for a while.
7.I myself now flush my black tank out good at least once a week weather it is full or not. I must admit I
usually do not use any chemicals I use Calgon fabric softener about one cup full.
When I am moving the first day I always fill my black tank half full of water and add Calgon one cup, Tide
laundry detergent one cup and one cup of bleach. When I then stop for the night I then fill my tank
completely full then flush good.
8.If you follow the above black tank maintenance you should not have any problems.
NOW I am not claiming by any means to be a black tank specialist, this is just my own personal
maintenance I have found over the years that works for me.
Hope this helps someone.
Bruce Cavanaugh