Do you know what is the most hated maintenance chore in an RV is? If you’ve answered flushing and cleaning the RV black tank, you’ve guessed right! It’s a nasty job but someone’s got to do it. Is it going to be you? Do you even know how to even empty and flush your tanks?
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Properly caring for your RV black tank will mitigate costly repairs and headaches down the road. To help alleviate that, we’ll show you how to properly flush and clean your black tank.
We’ll also throw in a few great black tank maintenance tips to keep it smelling fresh and clean.
But first, let’s learn about your RV sewer system.
About your RV Holding Tanks
Recreational Vehicles have three different tanks. Your RV water tank obviously holds your motorhome’s or camper’s fresh potable water.
The gray tank collects the dirty gray water from showers, washing hands, and dishwashing.
Your RV black tank holds whatever goes down the toilet. That said, some smaller RV’s bathroom sinks may empty into your RV black tank.
However, more often than not, debris from waste collects on those sensors; giving false indications on your gray and black tank readings.
To help alleviate that issue, you need to clean your tanks frequently to get rid of debris (sludge, paper, calcium, etc.) so your readings will be accurate.
It’s extremely important to keep all of your RV tanks clean and properly maintained or you’ll suffer nasty consequences caused by piling (piled up crap and toilet paper) and clogs caused by piling.
There’s controversy of whether to keep your RV’s gray tank open vs. closed. We keep ours closed per professional advice from our friend, Jim, owner of Kleen Tank RV Tank Cleaning Service.
He also recommends to wait until your black tank is at least two-thirds full before dumping.
When hooked up to sewer, it’s important to keep both gray and black tank valves closed until dump time as to not allow any waste to solidify or dry out in your RV’s sewer hose and connections.
How to Empty and Flush your Gray Tank and RV Black Tank
1. Put on your big kid gloves
On RV black tank maintenance and dump days, put on your disposable gloves before getting started because face it, this job is nasty!
2. Get out all your RV sewer accessories
After putting on your gloves. You’ll need to get out your RV sewer hose and accessories:
DO NOT use your blue or white drinking-water hose for flushing your tanks!
Let all occupants know not to use the bathroom during this process.
3. Tank Valves
Like we mentioned earlier, it’s recommended that you keep your tank valves closed. If you don’t, then close both, the black tank and the gray tank valves the right before cleaning.
4. Install Sewer Hose and Attachments
Remove sewer pipe cap on RV sewer discharge port. Attach your clear sewer hose adapter to one end of the sewer hose. Then attach that to the RV sewer discharge port.
5. Connect your hose
Attach RV bayonet elbow fitting to the other end of sewer hose and insert end into the sewer hole in ground. Make certain it’s secure. If it isn’t stable, place a heavy object on top to hold it into the hole.
6. Open black tank valve and let ‘er rip!
Open black tank valve first to discharge contents completely.
7. Open gray tank valve to flush
Open gray tank valve to discharge gray tank contents. This will also flush out existing black tank residuals from sewer hose.
8. Hook up water
Hook up all-purpose water hose to water spigot and black tank flush port. Turn on water at spigot to flush black tank until water runs clear through clear sewer hose adapter.
9. Secure water
Shut water off at spigot. Close black tank valve.
10. Disconnect hoses and attachments
Wait until water is completely flushed and sewer hose is empty before disconnecting clear sewer hose adapter and bayonet attachments. Stow sewer hose and attachments. Re-attach cap on RV sewer outlet port.
11. Clean toilet and add chemicals
Go inside and add one gallon of clean water into toilet bowl. Flush into black tank. Add second gallon of water to toilet bowl with toilet cleaning solution and clean with toilet brush. Add in rv holding tank treatment and flush into black tank to prevent piling.
Back Flush Method
The back flush method should be done at least once a month if you’re full-time RVing. And if you’re part-time or weekend camping, you should back flush at least quarterly to semi-annually.
After your initial dump and rinse, you’re going to close all valves and fill your black tank with water. Then you’re going to repeat steps 6-8 above.
The idea is to use as much water as possible to clean your RV black tank. The end result should be the water that flushes from your tanks to be clear
Some RV’s have a factory installed back-flush system. If you don’t have a factory installed back-flush system, you can easily install aftermarket systems.
Black Tank Treatment
As we’ve mentioned earlier, after you’re finished flushing your RV sewer system, then it’s time to add in the black tank treatment.
There’s three different black tank treatments you can use; the Geo Method, the Dawn Method or just us a commercial product.
The RV Black Tank Geo Method:
The GEO Method also breaks down water surface tension. We just flush it down your toilet. This ensures we won’t create the infamous poop pyramid in the bottom of the tank.
The environmentally safe GEO Method also cleans scum and prevents hard water deposits on the sensors.
You’ll need an empty five gallon bucket, 1 cup Calgon water softener, 1 cup Borax powder and 4 gallons of hot water. Then, mix Calgon, Borax and hot water in bucket thoroughly. Dump entire bucket of mixture into the toilet and flush.
The RV Black Tank Dawn Method:
Another is the Dawn method which is just as simple and supposedly performs similar to the above Geo Method.
RV Black Tank Commercial Product Method
If you prefer to use a easy drop-in black tank treatment, we recommend Happy Camper.
DO NOT PUT ANY CHEMICALS OR GEO METHOD IN YOUR WATER TANK!
Which toilet paper should you use?
It’s extremely important to use only septic-safe dissolvable toilet paper. Now, I’ll say this here. You don’t need to buy expensive RV toilet paper you see at the camping stores or RV section in big box stores.
“AFTER YOU GO, LOT’S OF H2O!!”
Just remember, when using your RV black tank; WATER IS YOUR FRIEND!
Tank Maintenance Tips from a Pro
Here’s what Kleen Tank recommends for tank maintenance:
Before leaving for your RV trip:
Fill gray and black water holding tanks about 1/3 full of fresh water. The sloshing motion of your moving RV combined with the water in the tanks will help break down solids, gently clean the tanks and help with the overall health and maintenance of your RV’s waste holding tanks
During your trip or while using your RV
Always keep both tanks closed (as we also mentioned above). Also, your tanks’ sensor panel should read 2/3’s to full before dumping.
If they don’t but you still need to dump because you are headed out to camp off the grid or boondock, you’ll want to top off both tanks with fresh water for an accelerated exit flow.
Also, anytime you leave the campground, dump the gray and black tanks and again. Fill each 1/3 full of fresh water for your trip home or next destination. This will help keep your tanks lubricated and the sloshing will minimize damage and repairs.
After your RV trip:
Top off both tanks with fresh water and dump before storing. Be sure to winterize your water system (if applicable) and add a lubricating antifreeze to tanks before storing long-term. This is a critical maintenance necessity.
That’s a Wrap on RV Black Tank Maintenance
And lastly, before you sign off from reading how we clean and maintain our RV black tank, take a moment to watch our video interview with a RV tank specialist on how to take care of our RV holding tanks:
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