How to Flush Black Water Tank

AldebaranJill
AldebaranJill Member Posts: 478
in Heating/Plumbing & Winterizing
Looking for best practices to flush the black water/grey water tank (mine is combined). One of those wands or the clear elbow fitting or ? Looking for actual experience, not theoretical :)
Thanks!
2013 MAXX T@B towed by a 2015 Volvo S60 5 CYL AWD Sedan
Seattle, WA -> Palm Springs, CA
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Comments

  • Verna
    Verna Member Posts: 6,876
    Clear elbow works best for me. 
    Verna, Columbus, IN
    2021 T@B 320S  Boondock “The T@B”
    Towed by a white 2019 Ford F-150 4x4 Supercab, 3.5L V6 Ecoboost “The Truck”
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  • AldebaranJill
    AldebaranJill Member Posts: 478
    Verna said:
    Clear elbow works best for me. 
    And I presume you need to be at a full hookup vs just a dump station since you need a threaded hose? 
    2013 MAXX T@B towed by a 2015 Volvo S60 5 CYL AWD Sedan
    Seattle, WA -> Palm Springs, CA
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  • db_cooper
    db_cooper Member Posts: 748
    I use one of these.  I have an RV dump out connected to our home septic, so I just flush it after several trips,  or if we don't dump before we come home.  Not cheap,  but it does appear to work,  I can see the jet of water blasting the tank when I look through the toilet hole.

    https://www.amazon.com/Valterra-SS01-Boxed-SewerSolution-System/dp/B00CCYWJQK/ref=sr_1_1?ie=UTF8&qid=1485015995&sr=8-1&keywords=sewer+solution
    2015 Max S Outback | 2010 Xterra  -- Retired
    2022 Ford F350 Tremor |  2022 Cirrus 620



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  • Verna
    Verna Member Posts: 6,876
    @AldebaranJill, pick up a Water Bandit (search on Amazon). It screws onto the clear elbow and will accept a bare end of a hose.
    Verna, Columbus, IN
    2021 T@B 320S  Boondock “The T@B”
    Towed by a white 2019 Ford F-150 4x4 Supercab, 3.5L V6 Ecoboost “The Truck”
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  • Dalehelman
    Dalehelman Member Posts: 2,414
    Drain black first then gray. Close valves use a bucket or some container to add 2-3 gals of water to black tank through toilet. Then open valve again. Repeat if you desire. I sometimes add some detergent to the water as well.
    1. Hash  T@B Fun
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  • Nomad
    Nomad Member Posts: 7,209
    Dale - I do as you but let that soapy mix travel and slosh around.
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  • Dalehelman
    Dalehelman Member Posts: 2,414
    PXLated said:
    Dale - I do as you but let that soapy mix travel and slosh around.
    I do as well not just every time. Always if I know I can dump again in the next day or two.
    1. Hash  T@B Fun
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  • dinzzy
    dinzzy Member Posts: 182
    I use this devise and have been very pleased. I also have a digital tank monitor which makes this much easier to do.  I have a sewer dump Connection at my home that makes this very convenient.

    https://www.amazon.com/gp/aw/d/B008O9DV78/ref=mp_s_a_1_8?ie=UTF8&qid=1485209350&sr=8-8&pi=AC_SX236_SY340_QL65&keywords=rv+tank+flush&dpPl=1&dpID=41d9qzPJodL&ref=plSrch

    Tow with a 2016 Tacoma TRD Sport, 2016 T@B CS-S Max


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  • AldebaranJill
    AldebaranJill Member Posts: 478
    Thanks to everyone - bought clear elbow and washing wand and got it cleaned out at previous stop where there was dump station. And @Verna your water bandit idea - It reminded me that I had one somewhere - found it this morning! 
    2013 MAXX T@B towed by a 2015 Volvo S60 5 CYL AWD Sedan
    Seattle, WA -> Palm Springs, CA
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  • Justin_in_Seattle
    Justin_in_Seattle Member Posts: 47
    edited September 2017
    In a previous post dinzzy mentioned the Valterra Flush King Reverse RV Flush Valve. This looks like a great product.

    Question, though... When you're back-flushing your black tank, what's to keep the black tank from eventually filling up and overflowing into the RV?

    Also, would it be worthwhile to reverse flush the gray water tank?

    Thanks for any info, RVs are new to me and I don't know much about plumbing. :-)
    2018 nuCamp T@B 400  +  2016 BMW X1 tow vehicle
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  • ChanW
    ChanW Member Posts: 3,165
    @Justin_in_Seattle, that's a good point. That's why I don't like the 'reverse flush' idea. I normally will stand inside the Tab, holding the flush valve open on the toilet, and fill the black tank fully with a hose while being able to see how full it is through the open toilet drain. It's a bit smelly, but not too bad if I make sure to have the ceiling fan blowing in, rather than out.

    It seems the only way a 'reverse flush' would work is if a second person stood in the Tab, watching through the open toilet drain.

    I'm also not sure what the point is to the reverse flush method.

    The gray tank flush is easier, because you can run water into the sink, while watching the shower drain for over-filling.

    Chan  -  near Buffalo NY
    2014 S Maxx
    2011 Tacoma 4cyl ... edit: 2022 Tacoma 6cyl - oh yeah! 

     A_Little_T@b'll_Do_Ya
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  • ChanW
    ChanW Member Posts: 3,165
    Here's an interesting analysis of some reverse flush systems:
    https://m.youtube.com/watch?v=dfTd0Slt_cU
    Chan  -  near Buffalo NY
    2014 S Maxx
    2011 Tacoma 4cyl ... edit: 2022 Tacoma 6cyl - oh yeah! 

     A_Little_T@b'll_Do_Ya
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  • jkjenn
    jkjenn Member Posts: 6,417
    ChanW said:
    Here's an interesting analysis of some reverse flush systems:
    https://m.youtube.com/watch?v=dfTd0Slt_cU

    I saw those, but they only really do one round and they don't use any enzymes.

    Justin_in_Seattle said:
    In a previous post dinzzy mentioned the Valterra Flush King Reverse RV Flush Valve. This looks like a great product.

    Question, though... When you're back-flushing your black tank, what's to keep the black tank from eventually filling up and overflowing into the RV?

    Also, would it be worthwhile to reverse flush the gray water tank?

    Thanks for any info, RVs are new to me and I don't know much about plumbing. :-)

    I backflush all of the time and have never had a problem with it overflowing into the RV. 

    2021 T@b 320 Boondock "Mattie Ross" | 2021 T@b Nights: 239 | Total nights in a T@b 455 | 2022 Jeep Grand Cherokee L Overland | T@b owner since 2014

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  • 4ncar
    4ncar Member Posts: 1,072
    I have seen the video too. What is compelling is the fact that using the hose fitted devices never realy flush beyond a bend in the pipe. So far my process has been to dump black, fill via toilet with a few gallons flush again(repeat until clear) put another gallon or two with enzyme..drive home. So far, so good...ready to go on next trip.
    TV- '16 Chevy Colorado LT Crew Cab-DuraMax
    2018 320S Outback
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  • jgram2
    jgram2 Member Posts: 1,522
    I really like the Valterra master Blaster tank wand @Verna mentioned and use it every few times we dump. Attached to the hose, held inside the tank, the force rinses sides and bottom pretty darn well and if you're not careful, holding down the flush handle with one foot and wielding the wand with your hand, you could almost work a shower in there.not saying that ever happened mind you.
    John, Judi, Guinness & OD in PDX
    T@Bit@t 2015 S Max Outback, ‘18 V6 4Runner 


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  • dsatwork
    dsatwork Member Posts: 744
    Two weeks ago, l was using the Rhino blaster on my single valve mod while testing my portable dump tanks and hoses. I remember seeing clear water coming out and thinking it wasn't really clean. However, I also thought that I had emptied the tank and when I checked it last weekend, I found it was 50% full, when I thought it should have been empty. So, apparently it does a better job of filling the black water tank, than I thought it was.
    2017 Tab Basic S Silver on Silver with Sofitel Cushions....upgraded from 2013 LG 5W....Towed by a 2016 Sorento V6 AWD w/5000lb tow capacity. Dave S. married to Jen aka SanDiegoGal We pull a Tab but live in a 2014 Airstream International Signature 27 FBQ...Talk about embracing a trailer lifestyle.
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  • Marceline
    Marceline Member Posts: 1,747
    AldebaranJill said:
    Looking for best practices to flush the black water/grey water tank (mine is combined). One of those wands or the clear elbow fitting or ? Looking for actual experience, not theoretical :)
    Thanks!
    Hi Jill -
    I have the same set up and I use the Rhino Blaster. As far as I can tell it works fine.
    https://www.etrailer.com/RV-Sewer/Camco/CAM39080.html


    San Francisco Bay Area
    2013 CS-S us@gi
    2015 Toyota Tacoma PreRunner Double Cab
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  • dinzzy
    dinzzy Member Posts: 182
    I watch my tank Gauge to make sure I’m not over filling.
    Tow with a 2016 Tacoma TRD Sport, 2016 T@B CS-S Max


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  • dinzzy
    dinzzy Member Posts: 182
    I continue to flush until clear water and no pieces of TP are coming through the clear 45 degree adapter I use.
    Tow with a 2016 Tacoma TRD Sport, 2016 T@B CS-S Max


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  • sdenhof
    sdenhof Member Posts: 43
    I am at fool hook up and wanted to give a flush a try. Do I just hook up a hose to the black flush out valve and open the black valve and watch the water flow through the clear elbow?
    2018 Tab 400 towed by 2013 F150
    Evanston Wyoming home
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  • dinzzy
    dinzzy Member Posts: 182
    I do this at home where I have (2) anti-syphon values, (1) at the faucet and the other on the end of the hose.  This keeps bacteria out of my home water supply.

    i have a hose dedicated just for this task.  

    With the “Flush king” attached I first drain the tank. Then I close the value on my “Flusk king” and open the black tank value. I then turn on the water supply attached to the “Flush King”.  I watch my tank Gauge.  When it gets to 90% I turn off the water.  I then open the value to the tank and check the contents.  Repeat until the water coming out is clear.
    Tow with a 2016 Tacoma TRD Sport, 2016 T@B CS-S Max


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  • ChrisK
    ChrisK Member Posts: 280
    dsatwork said:
    Two weeks ago, l was using the Rhino blaster on my single valve mod while testing my portable dump tanks and hoses. I remember seeing clear water coming out and thinking it wasn't really clean. However, I also thought that I had emptied the tank and when I checked it last weekend, I found it was 50% full, when I thought it should have been empty. So, apparently it does a better job of filling the black water tank, than I thought it was.
    How did it work with the single valve mod? I used to use one of these but figured it was just spraying in to the closed grey tank pipe so none went to the black tank.
    2014 T@b S Max AKA T@dpole
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