Single hose for fresh water and black tank flush

[JeffC]

I know this is discussed often but I could not find a thread dedicated to this subject and I wanted to see if we could find consensus on this subject.

I use a dedicated leader hose for convenience on both my fresh water and black tank flush inlets. Based on the knowledge of the vacuum breaker being well above tank level and bolstered with this diagram supplied by Cate&Rob in another thread, I have come to the conclusion that it is safe to run a single supply hose from city water to either of those inlets. This is not to be confused with using a hose splitter at the city water outlet.

I know many choose to run multiple hoses but that seems like a belt and suspenders solution to me. Thoughts?

[howson]

I know this is discussed often but I could not find a thread dedicated to this subject and I wanted to see if we could find consensus on this subject.

I use a dedicated leader hose for convenience on both my fresh water and black tank flush inlets. Based on the knowledge of the vacuum breaker being well above tank level and bolstered with this diagram supplied by Cate&Rob in another thread, I have come to the conclusion that it is safe to run a single supply hose from city water to either of those inlets. This is not to be confused with using a hose splitter at the city water outlet.

I know many choose to run multiple hoses but that seems like a belt and suspenders solution to me. Thoughts?

Yes, it is safe to use just one hose.

I choose to use two so I don't have to switch the hoses back and forth or interrupt the DW if she's doing something inside the camper, but it's really what works for each owner. As you've described in your post it is perfectly OK to do it either way.

[Country Campers]

This is what I have done to use just one hose.


This extends below the plastic tray and also has a valve on the end. The three valves allows to separate the sides.

Brian

[Cate&Rob]

JeffC
Hi Jeff,

I have long been the proponent of using a single hose. I know that this is counter to "conventional wisdom" and I have explained my reasons in the past, but I will summarize here.

The black tank flush connection cannot become contaminated if used properly. This requires connecting a hose to flush the tank and disconnecting that hose when finished to allow the vacuum break to do its job and drain all water from the flush line. Too often, those who use two hoses leave their "flush" hose connected. This may not allow the vacuum break to properly drain the flush lines within the trailer.

It gets worse . . . how often have you seen the black flush and potable water lines T'd together at the post faucet and then the owner turns off the faucet when they leave the camper?. Now, the full black tank flush line is connected to the full potable water line. The vacuum break is likely still able to overcome this, but a single failure there could cause contamination of the potable water. Water does not need to move for contamination to migrate through it, it just needs to be there.

Another benefit of using a single hose is that you are not likely to forget that you are flushing the black tank . . . an accident that we have all seen or at least heard about. The "failsafe" plan is to never have a hose connected to the black tank flush unless you are standing there watching it. Having a volume meter in the hose line really helps to understand how much you are putting into the black tank for flushing or prepping for the next period of use.

One caveat to this . . . you must always use a known clean potable water hose for the process described above. Never connect a dump station hose to your black tank flush. If you do this, you will have to go to a two hose system. Remember that you can use your own tank pump and water to connect to the flush line if necessary at the dump station and this maintains the clean potable connection. You can actually flush with hot water (at least 6 gallons worth) using your on board hose connection, whether on city or tank water.

Rob

[Guest]

My Imagine has a black tank flush at the LR of the unit by the gate valves and a fresh water fill at the LF in the passthrough as well as a gravity fill on the right middle of the unit. Using one hose is a personal decision where for us, a non-potable water tap is never used with our fresh water hose. I use a separate 6ft garden hose for the black tank flush. It's unsatisfactory that a potable water tap is located anywhere near a dumping station where this should not be IMO. Unfortunately, most every place does this.

Jim

[howson]

JeffC -- I learned what I know about the flush system from Cate&Rob. What I should clarify about my previous post is I unhook the second hose from the black flush when it is not actively in use. As Rob suggested, I use a metering valve so I know how much water has flushed through the system when the hose is connected and water is flowing. I also use the meter to put in exactly two gallons of clean water into the black tank once I'm done flushing (and the dump valve is closed) prior to a travel day. (If I'm home I just leave the tank empty.)

That's a lot of words to say I follow Rob's counsel on this system as I've found through my own checking that he's 100% correct in what he's written in this thread and previously.

Howard

[JeffC]

JeffC -- I learned what I know about the flush system from Cate&Rob. What I should clarify about my previous post is I unhook the second hose from the black flush when it is not actively in use. As Rob suggested, I use a metering valve so I know how much water has flushed through the system when the hose is connected and water is flowing. I also use the meter to put in exactly two gallons of clean water into the black tank once I'm done flushing (and the dump valve is closed) prior to a travel day. (If I'm home I just leave the tank empty.)

That's a lot of words to say I follow Rob's counsel on this system as I've found through my own checking that he's 100% correct in what he's written in this thread and previously.

Howard

Hi Howard,

I was going to ask about that very thing. Thanks for the followup. I also use a water meter.

-jeff

[mpking]

JeffC

One caveat to this . . . you must always use a known clean potable water hose for the process described above. Never connect a dump station hose to your black tank flush. If you do this, you will have to go to a two hose system.
Rob

Rob, thank you for pointing this out.

With the popup I've had for the last 5 years, we've dumped the cassette at the dump station, so I've been in there a bunch of times. I was not particularly paying attention, since it didn't apply at the time, but I'm pretty sure every place we've visit has *non-potable* water at the dump station.

So I think there is a second caveat to this. Don't use your known clean potable water hose on an UNCLEAN source.

I was fully intentioning to be in the one hose club, since I understand the engineering of the black tank flush. But I think outside factors will put me into the 2 hose club. I'd rather carry 20 feet of *bad* hose, than risk my family.

[Cate&Rob]

mpking

I can (kind of) understand the idea of a second “bad” hose and attaching this hose to a dump station faucet, if the black tank flush connection is somewhere separate from the water control panel and potable water connection. With most black tank flush connections in the same compartment as the potable water connection, bringing the “bad” hose into this area is just asking for a mistake and cross contamination. ( I would screw it up for sure )

If we need to use a dump station (which admittedly is rare for the camping that we do) I plan for this with how much water I put in the fresh tank before leaving the site. Then I use the outside shower connection and on-board pump to flush the black tank with (usually warm) potable water from the on-board tank. I have no need to carry a potentially contaminated flush hose and would never use a water source at a dump station for any purpose . . . just watch what others do with that hose or hose connection .

Rob

[JeffC]

If we need to use a dump station (which admittedly is rare for the camping that we do) I plan for this with how much water I put in the fresh tank before leaving the site. Then I use the outside shower connection and on-board pump to flush the black tank with (usually warm) potable water from the on-board tank.
Rob

That is a very good idea. What kind of adapter do you run on the coil hose to thread it into the BW flush inlet?

-jeff

[Cate&Rob]

That is a very good idea. What kind of adapter do you run on the coil hose to thread it into the BW flush inlet?

-jeff

Hi Jeff,

I was kind of anticipating your question and thinking . . . this post is going to raise more questions . . . LOL! (but I don't mind).

My 2015 Reflection "pre dates" the blue coiled hose. Back then, the original configuration was a (mickey mouse) outside shower hose. When I re-plumbed my entire system, I installed a quality hot and cold faucet plumbed to a quick connect hose fitting. The orange fitting above the faucets in the picture. This is similar in function to the connect where you plug in the coiled blue hose. I can plug an outside shower hose or a hose to the black tank flush (upper left in the picture) into this orange quick connect. I use quick connect water fittings on all attachments. Male for "water in" and female for "water out".

I would suggest that you might want to get another quick connect fitting to plug in where your blue hose plugs in with a hose specifically to attach to your black tank flush fitting.

Rob

[JeffC]

I would suggest that you might want to get another quick connect fitting to plug in where your blue hose plugs in with a hose specifically to attach to your black tank flush fitting.

Rob

This is too good an idea to pass up for the rare time you might need it. I especially like the idea of using my hot water to flush the black tank. Thanks.

This adapter should let me use my normal outside shower hose and connect it to the black flush port. Add the appropriate quick connects and Bob's your uncle.

https://www.homedepot.com/p/Everbilt...dalType=drawer

-jeff

[Country Campers]

This is too good an idea to pass up for the rare time you might need it. I especially like the idea of using my hot water to flush the black tank. Thanks.

This adapter should let me use my normal outside shower hose and connect it to the black flush port. Add the appropriate quick connects and Bob's your uncle.

https://www.homedepot.com/p/Everbilt...dalType=drawer

-jeff

The end of the sprayer actually screws into the black tank flush connection , same as hose end, kind of awkward but works. I do not have and uncle Bob though.

Brian