To Macerate, or Not to Macerate?

Being new to RVing, all I knew about dump tanks was summed up in movies like Christmas Vacation or RV.  I almost skipped getting an RV entirely, over the potential disasters that await.  Oh, did I say I was kinda squeamish about this?

Back in the day I had a (very) small yacht.  It had a simple onboard toilet, holding tank, and macerator.  Although usually trouble free, one time on a 3 day voyage from Long Island to Baltimore the toilet backed up.  I actually had to disassemble it and reach into the waste pool and free the clog, all on the high seas.  Is it any wonder I still have nightmares about this subject?

So anything to improve the RV dumping experience I’m down with…

When you start researching RV macerators the opinions and discussions pretty soon look like the Medieval dialog between Protestants and Catholics – there are 2 immovable sides, one “bad” and one “good”, depending upon where you stand.

The truth, I’ve found, like most things in life, is more nuanced and somewhere in between.

So, when I ordered my 2019 Leisure Travel Van Corner Bed, one of the check-off items on the order sheet was the macerator.

This is the Thetford “Sani-Con” Macerator.  There are actually 3 models: A portable one that you put on and off as desired, a box-style one for mounting under the RV, and the one pictured, which mounts semi-permanently to your tank discharge (pictured and the one LTV offers as a factory option).

In the photo the guy is holding the whole 21 foot retractable hose.

First, the arguments against having the macerator go something like this:

  • “I’ve been RVing for 99 years, and it’s just totally unnecessary!”
  • Its slower compared to the standard “stinky slinky”
  • It costs money
  • It won’t work if your battery is dead
  • Sooner or later it breaks while you are travelling, you are in for a nasty repair

This last one almost dissuaded me from having one.  I had a mental video in my mind of a dead macerator, full of fresh crap, and me having to crawl under my RV to remove it, 99 miles from the nearest town.  As soon as I remove it the rest of the contents of the blank tank discharge onto my face…

This is the kind of horror story that doesn’t need to happen, and in fact can’t actually happen, with a little planning and pitfall avoidance.  So let’s get this out of the way immediately.  The most common type of macerator, and the one LTV uses, twists on to your discharge tube like a slinky.

So in an emergency you can just twist if off and discharge the old fashioned way without too much trouble if you are reasonably handy.  But won’t you then have a macerator pump in you hands that is full of human waste?

Well, possibly, if you follow the usual instructions, which say to always discharge the black tank first and then the gray.  For obvious reasons, like flushing the pump and hose with (mostly) clean water.

Just add one simple step before that though.  Always first test the system with just a bit of gray water.  If your pump is broken or damaged, this is a good time to discover it.  Then if there is a problem at least your repair is not an especially dirty job.  If not, proceed with the black and the rest of the gray in order.

Of course, you could still end up with the pump burning up right in the middle of the black tank cycle, and no doubt about it, that is going to be a somewhat unpleasant job, but I am not going to spend my life worrying about that either…

So back to my review.  When I finally received my RV, I have to say I love this thing (well, as much as possible that you can feel love for a shit pump, anyway).  It is expensive, and it does take longer, but it really does make a nasty job somewhat less so.

In my book the less potential to get my hands dirty and the overwhelming convenience score in the macerators favor.  I literally just open the bay, extend this thing, and turn on the switch.  I almost look forward to dumping!

A few more caveats and notes.  First, if you look at the picture above, there is a cap on the discharge nozzle.  It makes sense to leave this on as there is always going to be some left over liquids in the hose and nozzle and you don’t want that dribbling into your bay later.

Don’t forget to remove the cap!

Don’t forget to remove the cap!

Even though I had been forewarned, I did the first time.  It’s easy to overlook.  Very bad things can happen.  If somebody is videoing you, you could end up on a viral youtube video.

That is especially true because there is one really terrible flaw with this macerator.  The discharge nozzle just pushes into the hose, with no threads or clamps.  If you just follow the instructions in the book, and dump the back tank first, I think there is a very high chance, if you forget to take the cap off, that the entire nozzle blows off.

At the point I really can imagine the hose could spew your black tank contents everywhere, including, uh, you.

So before you ever turn this thing on at the very least just get a 30 cent hose clamp at Home Depot and clamp the nozzle over the hose so it can’t blow off (or leak, which it will do).

Or, if you are even more pitfall avoiding inclined (like me) try something like this:

Besides clamping down on the connection and making it leakproof and blowout proof, I installed a bit of clear hose (but not all that clear!) so I can see whats going on.  This is useful because you can’t run this thing dry for more than a few seconds or it can be damaged, and its sometimes hard to tell by the sound pitch, so its always helpful to see into the hose.

The white cap, besides the facts that it is zip tied so you don’t forget and leave it behind, helps me to remember to remove in the first place.

As usual I went way overboard and built more than I actually needed. I started with this 10 foot extension hose:

Originally I was thinking that I would use this hose as an extension, giving me a great distance which would be convenient.  I realized on receiving it that it’s pretty large and stiff, and my ultra compact Sprinter RV didn’t have a good place to store this outside.  So I ended up just cutting off one end and using an adapter, plus some quick disconnect Banjo fittings.  The banjo fitting makes the nozzle removable if for some weird and unseen circumstance I wanted to discharge directly out of the hose (perhaps to weaponize the macerator in an emergency?)

Anyway, as I said I’m highly satisfied with the macerator.  With luck that’s the last time I will ever write on this subject until I die.

Here is the parts list for my clear adapter.  Do I really need 125 PSI quick disconnect banjo couplings?  Uh, probably not.  The rest of the clear extension hose is still in my garage in case I decide I really want a 10 foot extension.

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2 thoughts on “To Macerate, or Not to Macerate?

  1. Great article! You mention the parts list for your clear adapter but did not see it on the page. I would like to make this modification and thanks for passing this along.

    1. Hello and thanks for dropping by! I originally purchased the 10′ “Clean Dump” hose shown above with the intention of using it as an extension. However this clear hose is REALLY stiff and occupies a lot of space, so I just ended up cutting off a very small piece as shown in the picture. It would probably be a lot cheaper to just stop by the nearest Home Depot and pick up a piece of clear hose, although this is the way I ended up doing it.


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