A long-term free campsite for your RV is great. But what if there aren’t sewer hookups?
We took a work-camping position at a private ranch. Water and electric hookups were available but not a sewer connection.
We came in with empty tanks so had about a week to figure something out.
Pulling the RV out and taking it to a dump station wasn’t feasible - the site was not an easy in and and out situation.
Local honey wagon services estimated costs of $80/week and we weren’t sure they could actually reach us where we were parked.
The ranch owners had two possible spots to access their sewer system. One was about 50’ away and uphill, the other 150’ away but slightly downhill.
We decided to look into a macerator pump.
What’s a Macerator Pump?
If you haven’t heard of these before, think “garbage disposal”. They take the contents of your black tank and grind it up. Once ground up it can be pumped over greater distances through a smaller hose.
Hold onto that garbage disposal idea - we’ll come back around to it.
Some higher-end RVs have macerator pumps installed permanently. Rather than using a the standard RV “stinky slinky” the owners of these rigs play out a normal garden hose to a dumping point. The macerator grinds up the contents so they can flow through the smaller hose.
What We Bought
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Our RV is certainly not high-end so I shopped for and bought this Clean Dump CDTO Twist-On Portable Macerator System
It’s not the cheapest pump out there, but the reviews were better than others. I figured $50 in my pocket wasn’t going to help matters if the pump failed with a half-full black tank.
The Pumping Process
The overall process is pretty straightforward:
- Attach macerator pump to your RV’s sewer drain point
- Attach exit hose to the pump
- Run hose to an open sewer connection or into a toilet, etc
- Connect the pump to your 12V battery
- Pull your tank drain valve
- Turn on the pump
- Run it until the flow stops
- Turn the pump off
Here’s a video of an early use of our macerator pump:
Additional Lessons Learned
I used the macerator pump multiple times a week over a 10 week period.
I learned a few things since making that video.
Get a Clear Elbow
While running the pump you need a way of seeing what’s going on (if you have a weak stomach this entire process might not be for you).
You’ll need one of these clear elbows:
- You need to be able to see what’s coming out before it reaches the pump
- You need to be able to turn the pump off as soon as the flow stops (running the pump “dry” can burn it out)
- You need to see the results of your backflushing efforts
What you don’t see in my video (besides the clear elbow) is another hose added to the second water fitting on the pump. This hose lets you blackflush - which is basically shooting clean water back into the drain system.
When you pull the black tank to drain it the fluids come first. They drain pretty well. Towards the end of the drain more of the solids come out. And they don’t all come out.
Backflushing helps get those remaining solids out.
My black tank macerating process became:
- Let the pump empty the tank as far as it would
- Turn the pump off
- Leave the black tank drain valve open
- Backflush for 30-45 seconds
- Turn the pump back on
- Repeat this process 5-6 times until I could see through the clear elbow that no more solids were coming out
I would also occasionally use our RV’s built-in flushing system. In this case I’d:
- Turn off the pump
- Close the black tank valve
- Ask for help in not getting distracted right now
- Let the tank fill for a couple minutes
- Turn off the tank flushing (before the tank overfills, natch)
- Pull the black tank drain handle
- Turn on the macerator pump
Pre-Grind As Necessary
I learned to spot the big clumps coming out of the tank. These stress the macerator pump and make it overheat faster. When I saw one I’d:
- Turn off the pump
- Turn on the backflushing valve
- Let the backflush water pressure break up the clump
- Turn the backflush off
- Turn the macerator back on
Keep Fuses Handy
I blew a fuse once while dumping and the entire process stopped while I went off on a fuse hunt.
Once I found some I threw another couple in by my battery so if it happened again I’d have them handy.
Gray Tanks = No Problem
Using the macerator pump on the gray tanks was no problem. I could do both kitchen and bathroom tanks at one time without overheating the pump.
Macerator Pump vs. “Stinky Slinky”
By the end of 10 weeks I was so glad to be done with the macerator pump. I’m glad our RV doesn’t have one permanently installed.
- The tanks don’t get as empty without the suction effect you get with the standard slinky hose - even after 5-6 times of backflushing I’d still see solids/clumps coming out.
- The pump would often overheat, stop working, and needed time to cool down
- The process took up to 45 minutes for just the black tank
- The macerator is another “thing” to worry about breaking
- You still have to handle a “hose which carries the nasties” of some sort - just a thinner one
Other Macerator Options?
Most of the disadvantages of the macerator are due to it being a small-ish 12v pump. What if you don’t need to stay 12v?
Back to the garbage disposal we talked about earlier.
Crafty DIY sorts have figured out how to hack a DIY macerator using a garbage disposal unit.
I expect a 120v-based garbage disposal unit would be both faster and less prone to overheating.
Keeping the Pump?
We’ve been on the road over five years and haven’t needed a macerator before now.
Is it worth keeping?
For now, I am. Having it may open up some opportunities we hadn’t seen before:
- Longer stays in National Parks where there are only pit toilets
- Mooch-docking opportunities by friends’ houses
- Longer boondocking in places where we can’t find a dump station
Are You Macerat’in?
Or are you still using a stinky slinky at the dump station? I can’t recall ever seeing another RVer using a macerator. Have you? Let us know your experiences in the comments below.
Just wash your hands first.