Posted February 25, 2021 – Narrated by Jim
“Semper in excretia sumus solim profundum variat”
– Ancient Latin saying:
Translation: “We’re always in manure, only the depth varies”
It’s time to get down to business, the business we all doo.
As a retired Chief Financial Officer, I find that recreational vehicle black water tank maintenance is better understood from a financial perspective.
Risk Aversion is understandable and every RVers’ Risk Tolerance is personal. Me? I’m low risk. Why else would I be talking dollars and cents about fecal matter.
So, RVing Friends, let’s come to Terms. Our business with business deserves serious Appreciation, and it is our Fiduciary Responsibility to evaluate our Back-End Load and its Current Yield.
So take a moment to slip on a pair of gloves and draw a deep breath before we dive into the Fluid Economy of Gross Capital Flows.
I promise to guide this foray into Dark Pool Economics with the lowest possible Standard Deviation.
Call it an eMission Statement if you will, but to cover one’s Assets, it is vital that every RVer get in The Black.
Ever wonder what Investment insures that your Installment has Pass-Through Security?
Let’s flush this thing out.
What is Deposited down the toilet – from Flowing Liabilities to Gross Margins – ultimately winds up in the black water tank as a Short-term Liability.
Our Product Development through the Channels of Distribution becomes a Receivable.
Which in turn needs Inventory Turnover and Proper Positioning for the Moving Weighted Average to lower the Perceived Risk to an acceptable Tolerance Level.
While the Collection Period in this Safe Deposit Box is Short-Term, the Capital Input – which is Privately Owned – must be ready for its Initial Public Offering, its I Pee, Oh.
It doesn’t matter if our black tank is a mere 10 gallons or a whopping 40 gallons, the Economies of Scale require a Withdrawal once a Benchmark is reached.
This Intensive Distribution is easier with a proper Business Plan.
So let’s get down-and-dirty with our Return On Investment and find our Break Even Point of ideas, suggestions, tips, and procedures to keep our black water tank at a high level of Liquidity and on the happy side of our Balance Sheet.
“If ever you see a toilet in your dreams… Do not use it!!”
– Wise old saying
Here are the basics:
What is a Black Water Tank, (BWT)?
Everything that goes down the toilet goes into the BWT. All other drains, shower and sinks, go into the gray water tank.
Never leave the black tank open
Leaving our BWT valve open all the time would cause the BWT to be empty of any liquids. This would cause accumulation at the bottom of the tank causing solid waste build up, blockages and odors.
Only empty the BWT when it is more than half full.
It’s the Goldilocks rule. Emptying the BWT too often is not good. Waiting too long is not good either. But ⅔ or ¾ full is just right. Waiting for that sweet spot will provide the liquid volume to swish out most of those tank solids. NOTE: When done, be sure to completely close the BWT valve and secure the sewer cap. Do not ask how I learned this.
Empty the BWT before the gray tank
By emptying our BWT first, the soapy water from the gray tank flushes out the sewer hose (AKA: stinky-slinky) and the RV sewer outlet. This makes sewer hose storage a much more pleasant task, if that is even possible.
Always wear gloves
BWT maintenance is dirty business, so we wear disposable gloves. Some folks prefer reusable gloves, and that’s okay, but we discard the gloves after a single use.

Only use products designed for use with a Recreational Vehicle BWT
There are countless BWT treatment products at RV supply stores, both locally and online. After almost five years of traveling full-time and emptying our BWT more than 200 times, we give Unique RV “Digest-It” Holding Tank Treatment the LIB seal of approval.
It is 100% eco-friendly and doesn’t have that scary blue dye that causes stains. Now, with the Unique Digest-It method, our BWT tank is always odor-free.
Toilet Bowl Cleaner
We avoid toilet cleaners like Clorox, Comet, Lysol, or any anti-bacterial product containing harsh bleaches (chlorine, sodium hypochlorite, etc.) or hydrochloride acid, and hydrogen peroxide. These substances will kill off the bacteria which support an odor-free BWT.
For cleaning the toilet, we like Unique RV Toilet Cleaner + Holding Tank Enhancer. These two dynamic bio products merge to support a pleasant BWT environment.
But toilet seat disinfection cannot be compromised, so following tank-maintenance we use a Clorox Healthcare Bleach Germicidal Wipe and dispose of the wipe in the trash bin – never down the toilet.
The BWT needs fresh water as a base of liquid
Most bad odors and BWT blockages are caused by not having enough fresh water in the BWT after dumping. Do not ask me how I know this.
After emptying the BWT, we start fresh with enough water to make the tank-treatment chemicals work properly. With our 40 gallon BWT, we fill the toilet bowl with water, then add 2 ounces of the Unique RV “Digest-It” Holding Tank Treatment, and then flush.
Next, we squirt some Unique RV Toilet Cleaner + Holding Tank Enhancer around the bowl, fill the toilet with water, and allow for a 15 minute soak before flushing.
Tip: Clean the toilet brush by placing it in the bowl during that 15-minute soak. Nothing like starting fresh with a sparkling clean bowl and a clean brush.
That magic temperature – 85°
A cool environment is good for any live bacteria product. Unique RV “Digest-It” Holding Tank Treatment can only break down solids and stay effective if the temperature is right. The bio-colony in the BWT is threatened when the outdoor environment is higher than approximately 85°F. So play it cool when you’re at Burning Man. Pour some water down the toilet to lower that temperature and preserve the bacteria.
A little water in the bottom of the toilet bowl
Like pocket money, it’s insurance to always keep a little water – about an inch or two – in the bottom of the toilet bowl to create a water seal and prevent BWT odors from seeping into the cabin.
We just – ever so slightly – press the foot lever to release a smidgen of water into the bowl without opening the toilet ball valve.
The “X” Secret
RV toilets use very little flushing water. So, to keep things tidy we prepare by setting two 8-inch strips of toilet paper afloat over a couple of inches of water in the bottom of the toilet bowl.
This paper ‘X’ barrier before “the big number” not only helps to keep the bowl and bowl-valve clean, it also keeps the “down pipe” clean as your important business descends like a tidy toilet-paper-parachute.

Special Toilet Paper?
There’s an ongoing debate in the RV world about expensive RV toilet paper versus less expensive brands. And, as usual, the answer is more complicated than YES and NO. Yes, we need a toilet paper that breaks down quickly and a RV toilet paper like Scott Rapid-Dissolving for RVs and Boats does just that. YouTube is filled with tests displaying disintegration speed results on all the major brands. Angel Soft works great for us, at a fraction of the cost of Scott RV.
Here’s a quick test for toilet paper disintegration: Tear off a single sheet of paper and place it in a glass of water. Allow it to soak for an hour. When the hour is up, take a look at it. Is it dissolved or is it still intact? There’s your answer.

BWT Blocked and will not empty?
Five years ago, as newbies, our BWT refused to empty. Shortly thereafter we published the blog post, We Met The Enema, and It Is Us, which explains how we dealt with a complete BWT blockage.
And we call BS on the myth that ice unblocks a BWT.
Here’s proof that ice down the toilet doesn’t work:
Don’t buy a cheap sewer hose
Don’t be penny-wise and pound foolish. We could have bought a sewer hose for as little $7 and as much as $115. After experimenting with several brands, we have settled on the RhinoFLEX RV Sewer Hose. Our current hose has lasted more than six years and still works great, looks good and has no leaks.
UPDATE June 2022 – Since we published this blog post in February 2021, our 6-year-old sewer hose sprung a leak, so we upgraded to the RhinoEXTREME Sewer hose. While our cheaper hose lasted a long time, we decided to get the best sewer hose available when we needed a new one.
Have a sewer hose extension
We’ve encountered more than a dozen campsites where a sewer hose extension was necessary to reach the sewer connection. In those rare situations, we are grateful for our RhinoFlex 10 foot sewer extension. Sometimes, even two are necessary.
Sewer Hose Support
While it is not technically necessary to use a sewer hose support, there are good reasons to use one.
- It keeps the sewer hose off the ground, making it last longer. And, it supports the hose so you don’t accidentally step on it while walking the dog in the middle of the night. Do not ask me how I know this.
- The sewer hose support helps gravity do its job.
- Some campgrounds require a sewer hose support, so it’s necessary equipment to have onboard.
- While using the support, we can create a ‘water trap’ which blocks any gases or sewer flies (and worse!) from entering into our black or gray tank while the tank valve is open.
Built-In BWT Sprayer
Some RVs come with a built-in BWT spray head. When a fresh water hose is attached, it’s supposed to flush out the inside of the tank.
Our experience has shown that while it does clean some debris from the tank, it does a lame job. So we don’t use it. Instead, we use the Valterra Reverse RV Flush King Valve.
Warning, warning, warning!
Avoid the very common newbie mistake of confusing the city water inlet with the BWT spray head inlet. They are both threaded for a water hose. So, if you’re not careful you may think you are filling up your fresh water tank with city water but you are actually filling up your BWT. At best, this could be an embarrassing mistake, at worse it could cause toilet overflow and disastrous results in your RV. Read the label (if there is one) next to the inlets before proceeding. Again, do not ask me how I know this.
Keep the BWT Sparkling Clean (Well, kinda…)
Every time we empty our BWT, we use the Valterra Reverse RV Flush King Valve. With this cool gizmo, we refill the BWT with fresh water several times to help flush out stubborn contents and avoid a blockage.
We go into great detail and explain how we use this in our blog post: We Met The Enema, and It Was Us.
The Valterra “Sewer Solution” Pulverizing System
While we haven’t used this product, many RVers swear by the Valterra “Sewer Solution” System.
It pulverizes the black water tank contents and sends it down a small 1″ hose, instead of the traditional 3″ sewer hose. We only mention this as a reference. If you use it, please give us your review.
Doin’ The Stinky Slinky Crawl
When disconnecting the sewer hose from the RV, we do the ‘Stinky Slinky Crawl.’ First we carefully unhook the sewer hose from the RV, then promptly raise the end so all hose content drains down toward the dump station receiver into the sewer. This insures the hose is completely empty before disconnecting.
The Blaster Tank Wand
The Valterra Blaster Tank Wand BWT treatment is one of those extra-mile things. Do not be deceived by this seemingly harmless, quirky-looking thingamajig because …
… it blasts the livin’ holy blazin’ daylights out of the freakin’ BWT with high pressure water of insane velocity, producing such a disorienting racket that I feel violated when the thing is done. But, on a positive note, it dislodges any and all remnants of our former selves and sends each and every particle of whatever down the drain as if it never happened.
If you have to replace your toilet
If, for any reason, the toilet needs to be replaced, we highly recommend the Dometic 310 toilet with sprayer.
This toilet has a perfect water distribution over the bowl when flushing, and the hand sprayer is a nifty tool to keep the bowl clean. Also, if the bowl valve starts leaking, it only takes about a minute to replace the rubber seal – no removing the toilet or any kind of disassembly is necessary.
BWT Sensor
The BWT sensor, located inside our tank, became dysfunctional years ago. Recently, we installed the Garnet SeeLevel sensor system on the outside of all the tanks. Now, we are confident the monitor is reading our tank levels accurately.
Like finance, BWT Maintenance is a practice, a science, and an ongoing journey – an investment in a chosen lifestyle.
As Americans we have this aversion, but modern mobile lifestyles are changing all that. So, explore. Be confident, creative and clean. Have fun with it. And most of all, don’t let the sewer hose wag the RV.
If you have an RV BWT tip or suggestion, or if you use an alternative like a compost toilet, we’d love to hear from you. Please share in the comments section below.
Products we use
We have listed all of the plumbing related products and tools we use to keep our Airstream trailer in tip-top condition.
Related Topics
Our post – Water, Water… – discusses RV water usage, conservation and filtering techniques, tips and suggestions.
Our post – Hot Stuff – discusses our solar power setup along with our lithium batteries.
Special thanks to the following for their help and input on the blog post:
- Aimee Varghese, Consumer Relations Manager at Unique Camping + Marine
- Larry Cook, master Airstream guru, and the guy we bought our Airstream from in 2015.
- Vinnie Lamica from Vinnie’s Northbay Airstream Repair
If you want to see our exact route, click here.
*photos in this post (unless otherwise noted) were taken and copyrighted by Living In Beauty.
