Fresh Water / Black Tank Flush Mod

Charles.maine · 07-05-2017, 01:51 PM

So for a little over a year now my biggest grip about hooking up services to my fifth wheel is when I have to swap between fresh water and tank flush. For example we pull into our spot late evening and we hook up the hose to the black tank flush (just to get some water in there) and without fail within a matter of seconds I hear a voice from inside. "If you would hook up the water I could start on dinner!!"

So I finish putting water in the tank and then swap the water hose over to the fresh side. Everything is fine until it comes time to empty the black tank again. Without fail I always see an opportunity to do it while someone is in the shower or while she is washing dishes. Again that will not work. Or when we are packing up to leave and I want to flush the tanks and I hear that voice again, "I need water to finish these dishes/clean up etc."

So I had this idea. I actually did it several months ago with the use of water hose tees and elbows. However it was not lined up perfect and was very difficult to maneuver. So finally today I ran into the hardware store and picked up a few things and here is what I came up with.

Both sides have shut off valves and there is a quick connect at the bottom. I hooked everything up and no leaks!! The boy is super excited about the quick connect. As he is usually the one handling the water hose.

** Not really sure why the pics uploaded sideways. That is weird. **

JustB_Rad · 07-05-2017, 01:56 PM

Quote:

Originally Posted by Charles.maine

So for a little over a year now my biggest grip about hooking up services to my fifth wheel is when I have to swap between fresh water and tank flush. For example we pull into our spot late evening and we hook up the hose to the black tank flush (just to get some water in there) and without fail within a matter of seconds I hear a voice from inside. "If you would hook up the water I could start on dinner!!"

So I finish putting water in the tank and then swap the water hose over to the fresh side. Everything is fine until it comes time to empty the black tank again. Without fail I always see an opportunity to do it while someone is in the shower or while she is washing dishes. Again that will not work. Or when we are packing up to leave and I want to flush the tanks and I hear that voice again, "I need water to finish these dishes/clean up etc."

So I had this idea. I actually did it several months ago with the use of water hose tees and elbows. However it was not lined up perfect and was very difficult to maneuver. So finally today I ran into the hardware store and picked up a few things and here is what I came up with.

Both sides have shut off valves and there is a quick connect at the bottom. I hooked everything up and no leaks!! The boy is super excited about the quick connect. As he is usually the one handling the water hose.

** Not really sure why the pics uploaded sideways. That is weird. **

That looks like a quick way to contaminate your fresh water without a back flow preventer.

Charles.maine · 07-05-2017, 02:01 PM

I can throw one of those on there. Actually will have to add them to both sides to keep the angles right.

Decon Blue · 07-05-2017, 02:03 PM

Quote:

Originally Posted by justb_rad

that looks like a quick way to contaminate your fresh water without a back flow preventer.

agree !!! 😱😱😱

5picker · 07-05-2017, 02:07 PM

Quote:

Originally Posted by Charles.maine

So for a little over a year now my biggest grip about hooking up services to my fifth wheel is when I have to swap between fresh water and tank flush. For example we pull into our spot late evening and we hook up the hose to the black tank flush (just to get some water in there) and without fail within a matter of seconds I hear a voice from inside. "If you would hook up the water I could start on dinner!!"

So I finish putting water in the tank and then swap the water hose over to the fresh side. Everything is fine until it comes time to empty the black tank again. Without fail I always see an opportunity to do it while someone is in the shower or while she is washing dishes. Again that will not work. Or when we are packing up to leave and I want to flush the tanks and I hear that voice again, "I need water to finish these dishes/clean up etc."

So I had this idea. I actually did it several months ago with the use of water hose tees and elbows. However it was not lined up perfect and was very difficult to maneuver. So finally today I ran into the hardware store and picked up a few things and here is what I came up with.

Both sides have shut off valves and there is a quick connect at the bottom. I hooked everything up and no leaks!! The boy is super excited about the quick connect. As he is usually the one handling the water hose.

** Not really sure why the pics uploaded sideways. That is weird. **

You are going to get a lot of comments about tying the fresh water and the black tank flush together, valves or no valves but I won't go there...

I will however, touch on something you mentioned that I highlighted in red above.

You really should NEVER experience the situation you outlined as there should ALWAYS be water in your black tank. If you pull into a campsite late, early or anything in between, you should be ready to go by having put some water in your black tank after your last dump.

Before leaving the campsite (or dump station or wherever you empty) once dumped and flushed, the black tank needs to have some water put back in it to keep any remaining solids from hardening. Yes I know you are going to say, "well if I've flushed, there isn't anything in there to harden." But, there is. You never get it sparkling clean and without several gallons of water, you are asking for trouble.

I also add my chemicals in at this point (for the next stop) and the sloshing of the water/chemicals going down the road has kept us trouble free for 40+ years.

Charles.maine · 07-05-2017, 02:14 PM

You think with the back flow preventer and the valves being shut we will be fine? I cannot imagine how I wouldn't be.

DrLewie · 07-06-2017, 01:18 PM

Some folks (I'm one) also use different hoses for fresh water connection/fill and tank flush. Even with a back flow preventer there is the chance of stuff you don't want in your drinking water to contaminate the fresh water hose. I picked up one of those cheap collapsing hoses for the flush job. They collapse to almost pocket size but expand enough to reach the water tap in every campsite I've ever stayed in. As mentioned by others, I would never do a setup like you did...not worth the risk.

rlh1957 · 07-06-2017, 01:24 PM

Bacteria migrates no matter what type valve you have. You cannot connect or let fresh potable water supply or tanks ever come in contact with a Grey or Black water tank or supply.
Only the lucky can say they never had an issue.

emm-dee · 07-06-2017, 01:47 PM

I made a quick connect hose that plugs into the outside water outlet. Turn the handles on and activate the flush.

itat · 07-06-2017, 02:15 PM

Hopefully Columbus installed a backflow preventer somewhere in the line between the flushing port and the black tank. If they did, and if it's working, you haven't contaminated anything.

We all use a single water source to feed the fresh water side and the blank tank flusher. You have to have the backflow preventer on the black tank flush line to ensure you won't accidentally contaminate the source water supply.

I have a dedicated garden hose for flushing the black tank and I use an external backflow preventer at the flusher port to ensure nothing makes its way back to the water system. I use a brass wye fitting (with both sides valved) at the tap and never have the valves on both sides open at the same time to reduce the chance of developing a vacuum condition in the black tank side when drawing water on the fresh side. But the backflow preventer is the only way to ensure nothing gets from the black tank into the water supply.

kollinr · 07-06-2017, 02:57 PM

Why not just hook up the fresh water hose and go flush the toilet for a minute or two while your wife is starting dinner?

bubbles · 07-06-2017, 04:04 PM

Why not just hook a wye spout with shut off capability to the camping faucet with another hose attached. It is quite apparent that a lot of the posts are from individuals that have not a clue how a black tank clean out system is installed by the manufacturer. There is a spring loaded back flow/vacuum control valve installed that is several feet above floor level. There is no contamination.

emm-dee · 07-06-2017, 04:20 PM

The flush outlet is not at the bottom of the tank...it's at the top. Someone is going to have to explain the new law of physics that explains how the contents of the tank is going to mysteriously jump through the air above it in order to enter the line to the hose inlet.

Not gonna happen.

itat · 07-06-2017, 05:25 PM

Quote:

Originally Posted by emm-dee

The flush outlet is not at the bottom of the tank...it's at the top. Someone is going to have to explain the new law of physics that explains how the contents of the tank is going to mysteriously jump through the air above it in order to enter the line to the hose inlet.

Not gonna happen.

Vacuum condition will allow contamination.

emm-dee · 07-06-2017, 05:39 PM

Quote:

Originally Posted by itat

Vacuum condition will allow contamination.

How is this vacuum condition created. Even if you removed the charcoal valve and put a vacuum cleaner hose on the inlet all you'll get is smelly air.

pdqparalegal1 · 07-06-2017, 05:52 PM

Why not keep a small supply of fresh water in the tank to run the pump for your wife's needs while you flush etc.?Just curious.

NMWildcat · 07-06-2017, 06:56 PM

While there are several other viable and easier solutions to the OPs original 'problem', I don't see any difference between what he did and what I see frequently done, which is using two hoses and a 'Y' fitting at the park spigot. He just moved the 'Y' closer to rig which eliminates a hose. As long as he doesn't have a black flush backflow preventer and/or valve problem, I would think his solution is fine.

richp · 07-06-2017, 09:12 PM

Hi,

I use a separate black colored hose for all my black tank activity -- no chance of cross contamination confusion.

As a backup to the backflow prevention valve, I installed a manual cutoff valve on the black flush intake fitting. This gives me positive control of the water flow right at the panel.

Like most folks, I dump and flush black first. After I close that dump valve and kill the flush, and while I'm dumping the gray tanks, my wife goes inside and adds 3-4 full toilets full of water back to the black tank. This gives a nice "slosh" factor as we go down the road, agitating any remaining residue and keeping the tank wet until the next trip. With long intervals between trips in real hit weather, I have been known to add an extra five gallon jug of water, just for insurance against evaporative loss.

FWIW.

Rich Phillips

hybridlife · 07-06-2017, 09:17 PM

Not trying to hijack the OP thread, but along the same topic...how much water are you leaving or "putting back in" your black tanks as a slosh agent? On a 30 gallon tank is 1-2 gallons enough?

m

richp · 07-06-2017, 09:49 PM

Hi mfeeley,

I figure each full toilet of water is at least a gallon, probably more. So I'm in the five gallon range after she dumps it 3-4 times. And like I said, for hot weather and prolonged storage between trips, I add more just to avoid having a layer of baked effluent on the bottom of the tank.

Hope this helps.

Rich Phillips

You may also like: