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Flush King Reverse Flush Valve for RV Holding Tanks and Sewer Hoses - 3" Diameter

Flush King Reverse Flush Valve for RV Holding Tanks and Sewer Hoses - 3" Diameter

Item # F02-4350
Our Price: $47.70
You Save: 39%
RV Waste Valves
Shipping Weight: 1.96 lbs
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Flush valve allows you to rinse out your wastewater tanks and flush out your sewer hose, breaking up clogs and cleaning tank sensors. Built-in backflow preventer keeps water source contaminant-free. Clear barrels shows when tanks are clean. Great Prices for the best rv waste valves from Flush King. Flush King Reverse Flush Valve for RV Holding Tanks and Sewer Hoses - 3" Diameter part number F02-4350 can be ordered online at or call 1-800-940-8924 for expert service.
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Flush King RV Waste Valves - F02-4350

  • Single Waste Valve - Manual
  • Flush Valves
  • Flush King
  • Stationary Valve

Flush valve allows you to rinse out your wastewater tanks and flush out your sewer hose, breaking up clogs and cleaning tank sensors. Built-in backflow preventer keeps water source contaminant-free. Clear barrels shows when tanks are clean.


  • Flush valve allows you to force fresh water through your holding tanks and sewer hose from outside of your RV
    • Breaks up clogs in plumbing lines
    • Cleans tank probes to help prevent false readings on monitors
    • Eliminates the need to use tank wands and rinsers
  • Built-in backflow preventer keeps water source free from contaminants
  • Clear barrel lets you see when your tanks are clean
  • Blue knob allows you to direct the flow of water
    • "Tank" backflushes your black-water and gray-water tanks
    • "Hose" rinses your sewer hose
    • "Off" stops the flow of water
  • Valve handle swivels 360 degrees for easy operation
  • Simple installation and removal - no tools required
    • Easily refill and flush tanks at any height or bend of plumbing
    • Bayonet fitting secures to standard 3" lug fitting on RV's waste valve
    • 3" Lug fitting allows you to connect to sewer hose
    • Rinse hose (sold separately) connects to the female coupling on barrel
    • Inner seal helps prevent leakage at the connection point

F02-4350 Valterra Flush King Reverse Flush Valve for Motor Home Holding Tanks and Drain Hose

California residents: click here

Customer Satisfaction Score:

Customer Reviews

Flush King Reverse Flush Valve for RV Holding Tanks and Sewer Hoses - 3" Diameter - F02-4350

Average Customer Rating:  4.8 out of 5 stars   (106 Customer Reviews)

Flush valve allows you to rinse out your wastewater tanks and flush out your sewer hose, breaking up clogs and cleaning tank sensors. Built-in backflow preventer keeps water source contaminant-free. Clear barrels shows when tanks are clean.


Who decides on size of box for shipping and do you train them on securing product for shipment? I ordered two wiper blades, two heater door clips, sewer flush king and sewer cap. They were shipped in a huge box (21"x26"). So big that the flush king came out of its packaging from being tossed around inside the box. I'm sure everything was bounced around the entire trip to my door cause there was only one small strip of filler for cushion and the box was crushed onretailer. It could have been shipped in a box half that size. I'm actually not expecting my flush king to stay together long. Disappointed in the shipping package. I guess you take your chances. I never expected this from etrailer.


Great service fast delivery

Richard P.


Working out well but some times it leaks


The valve made flushing both tanks easier than putting a hose inside the camper trailer.



The product works great especially when I am by myself when flushing the tanks.


Best thing since the invention of Duck Tape. This gadget saved the day with my kitchen gray tank that wouldn’t come unclogged no matter how much baking soda, vinegar, Dawn and hot water I used. A definite must have for any RVer.


I have not had opportunity to use the unit yet, but did take it out of box and installed unit. The picture on web site makes it look like the valve gate would be against the exisiting pipe, but it is just the opposite. When installed on my Terra Oasis, it sticks out past the trailer tire, so I don't think I would want to leave it on while traveling.

Etrailer Expert

Katrina B.


I would definitely agree with your review. We do not recommend permanently mounting this item. We have heard of some people doing this but to get the best, longest-lasting use out of this we highly recommend only using it when needed as opposed to keeping it on when you are traveling.


Great service and products delivered as scheduled. I will begin installation in about one week and attach pictures and give update.


VERY impressed with product, my first time "back-flushing" the black-tank & was impressed with the amount of dried toilet paper flushed! A+++


Works great for our fifth wheel that didn’t come with a factory installed black tank flush system. Use this every time we are done camping and the smells are gone and tank sensors read as they should. Well worth the money!


I had one of these and just loved the way it worked and helped me be sure my holding tanks were clean and empty. Unfortunately, on our recent trip something apparently came up off the road and made it disappear as well as breaking a fitting on the line coming from the trailer. I've gotten so used to using this that I really hated to dump without it.

We buy quite a bit of things from Etrailer for our business equipment and my RV. Always get good service.


Wow this thing works! I not only cleared a black tank stoppage that prohibited the black tank frm draining at all, I cleaned both the grey and black tanks...

My neighbor is using it this week to clean his tanks as well - this is a device that is now built in to some of the newer RVs, because its needed and works so efficiently,,,

Scott W.


Sensor s can get fouled and distort actual tank levels this litle guy is perfect for cleaning out the tank and removing old slime, etc etc etc


Very helpful and informed staff. Guided me to the exact product to meet my requirement's.


I just received my order this afternoon. Very surprised at the speed with which it was delivered. I am in the process of rebuilding a older5th wheel and the items that were ordered are just perfect for the job.
Thank-you etrailer I will be back


The Flush King worked like a champ! I was able to flush out my black water rv tank and not get not get dumped on in the process. I really liked the fast delivery by etrailer also! Great company to do business with!


Works just as it should. It’s really nice to see what’s going on when you dump the tanks because without this valve you really don’t know.


Love their shipping app! Arrived very q uickly


I purchased the Flush King device to solve a problem I had with Black Water Valve not closing all the way. I suspected some type of debris was causing the gate valve to not seat correctly. The Flush King device allowed me to back flush the line near the source of the problem and the dump valve is now working great. Every RV owner should have access to the a Flush King device to keep your dump tanks free and unobstructed.

I also purchased a wand so I can flush the Black Water Tank from above. This is a great tool for cleaning sensors and pipe between toilet and tank.


Looking forward to flushing our system!



Have not had much success so I purchased a “wand” to flush the black tank. Success meaning the tank gage is reading accurate


Works great, if you don't have a black tank flush port on your trailer.


Product worked great. Black water tank was clogged bad. Paper had dried hard over drain. 1 place told me I needed another tank. Another place put chemicals in but that didn’t work. I tried snakes and nothing worked. The flush king blew the clog apart and everything worked flawlessly. Great product


Used one time. Worked PERFECT!!!! Wife was ecstatic!!!! WE had a black tank that wasn't draining. Installed the device. pressurized the system and it blew the clog out. Back washed a couple times, haven't had a problem since. Anyone who owns an RV should have one. Wish I had found it sooner. Thank you


I haven't used it yet but it does look to be exactly as advertised except it did not come with with the backflow preventer. I am excited to try it on our next trip out in a couple of weeks. I'm knocking off one star only because it was missing the backflow item.

Etrailer Expert

Brooke M.


Thank you for leaving a review! Our customer service should be reaching out to you in the near future.


I had a clog in the outlet of the black water tank. I ordered this from George on a Sunday. It shipped on Sunday much to my surprise. Came to me in excellent condition. I hooked it up and it worked as advertised. Cleared the clog and cleaned the tank. I flushed it about 3 times and was getting clear water. It also cleaned the sensors so the tank is showing empty. Its been 2 years since they have worked. Excellent product and excellent service


The best trailer accessory ever. It is working great after a year. No leaks. Versatile. Rotates to accommodate the various geometries of the curbs at dump stations. Two back flushes usually gets everything cleaned out of the black tank. The clear pipe shows it is working perfect! If this ever breaks I will buy the exact one again.


Great Product


I love this device. Really gets my tanks flushed out. It’s very easy to use.

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