A Simple Solution for Boat Toilet Stink

Posted by Darrell Nicholson with Drew Frye at 11:06AM - Comments: (12)

Photo by Drew Frye
Photo by Drew Frye

Forespar Refresh was one of several products that we found effective when diluted and put in a spray-bottle for daily use.

Your home toilet receives a plentiful washing and a dose of disinfectant every time it is ­ flushed thanks to chlorinated city water piped to our homes. A marine head is different, whether flushed with sea water or fresh water. Flush volume is limited, as we like to stretch pumpouts, and often have to. Inevitably, a few spots and stains are often left behind.

In the case of seawater ­flush, the water in the intake line and bowl will begin to stink, a result of anaerobic processes converting sulfate in seawater into hydrogen sulfide, resulting in the familiar rotten-egg odor. But no one enjoys scrubbing the head while on holiday, and we’ve been warned that common grocery-store cleaning products mean death to healthy holding tank bacterial cultures. So what is the solution?

The holding tank treatments themselves hold the key. Our two-part report on holding tank treatments highlighted some very effective products—and some not so effective. One of the better performing additives, Raritan CP (Cleans Potties), contains surfactants, bacterial cultures, and a mild perfume; sprayed in the bowl after each use, it silently eats away and dissolves the mess without user intervention. And since the culture and chemicals are compatible with a bio-augmentation approach to holding tank odor control, any product that is ­flushed is a benefit, starting treatment at the bowl and cleaning the entire system.
Will other holding tank treatments that stood out in our two-part report do the same—cleaning the bowl and keeping the head compartment fresh? Yes, at least some have shown they will.

We’ve not had time to evaluate all of our recommended holding tank treatments when used in this manner, those that we have tried worked well.

We tested each candidate treatment by diluting about 5:1 with water, placing the mix in a trigger-style spray bottle, and misting the toilet bowl after each use, or at least a few times a day. Could the solution be used at full strength? Perhaps, but we found that unnecessary.

Avoid bacterial cultures; while they may be very effective in the tank, we found they start to grow in the sprayer, clogging the nozzle. Raritan CP has formulated a way around this problem apparently; simply follow labeled instruction. Liquid enzyme and nutrient types work, though some were too strongly perfumed for our tastes. We preferred those with a very mild scent. Our favorites to use in the bowl are, in order of personal preference: Raritan CP, Forespar Refresh, Camco TST Ultraconcentrate Citrus, and Thetford Ecosmart. The bowl stays cleaner, and the stink that is all too common when the boat has been closed up for a week will be banished.

For a more comprehensive looks at improving your boat’s marine sanitation system, our two-part ebook on marine sanitation covers everything from system design to routine maintenance.

Comments (12)

I would like to second the comment on white vinegar. We've started using it for everything onboard and love it - it's $2.50 for 3 gals at Costco and goes a long way.

Posted by: Tony@svmarite | June 6, 2017 2:37 PM    Report this comment

Aboard for 25+ years. We clean head with a little distilled wht vinegar and use cheapest veg oil occasionally. Never have problem w/head unless we have company.

Posted by: Songndance | June 3, 2017 1:55 PM    Report this comment

Wye valves aren't enough in the Great Lakes, especially now that Canadian and U.S. Coast Guards are collaborating in stop-and-search inspections. Ensure the valve is switched to holding tank and the overboard through-hull is closed and the handle removed. Protests that a number of Great Lakes cities routinely discharge untreated sewage into the lakes and the St. Lawrence cut no ice with these folks.

Posted by: jimduff | June 2, 2017 9:52 AM    Report this comment

Yikes! A Ord you need to get that fixed. Per Federal Clean Water Act It is illegal to discharge raw (untreated) sewage into any public waters. You can't pump overboard unless you are 3 miles offshore! You should look to see if there is a holding tank in the bilge. If the boat was equipped for ocean sailing there might be a Y value to allow deposits to go overboard or into a tank. If you bought it thru a broker or if there was a survey and that wasn't revealed I'd be sending them the bill. Very irresponsible and if you are caught the fine is large not to mention how would you like to be swimming in that water while someone is using the head? Most poop floats, yuck! Just look online and you'll find info on how they should be setup and check your states rules for specifics. Try West Marine's website for Marine Sanitation. Good luck.

Posted by: cfoam | June 2, 2017 2:32 AM    Report this comment

The olde advice for keeping the valves operating smoothly was to flush a tablespoon or two of MINERAL oil twice a year. As for one source of Stink --- I wrapped the hoses, which carry 'stuff' from the bowl to the tank, with SARAN wrap (not just any plastic wrap, but SARAN). It kept that source of odor at bay for many years. As for the holding tank itself, an additive (maybe Raritan CP) is good advice.

Posted by: RogersEH | June 1, 2017 2:13 PM    Report this comment

Olive oil and canola oil are less damaging to neoprene parts (Jabsco and Groco heads--Rairitan uses nitrile, which is more oil resistant). However, PS testing correlated regular doses of cooking oil to sludge build-up. This is why it is is illegal to dispose of cooking oil into sewers--it gums things up. Better, grease the pump with synthetic grease annually, as the manufacturers recommend.

None of the head treatments recommended by Practical Sailor--including Refresh--have any negative effect on head components. Some of the traditional blue treatments can damage head pumps and hoses.

Posted by: Drew Frye | June 1, 2017 10:47 AM    Report this comment

I just got a MacGregor 25, 1982 just two days ago, i've got the same issue old school toilet pumps right out the hull, my first thought was to put in a holding tank i was thinking a ten gallon but now I'm not sure, so with the porta potty you can just pore it down any toilet, are they user friendly just dump and go

Posted by: macgregor82 | June 1, 2017 9:35 AM    Report this comment

Regarding the olive oil treatment, it's been demonstrated (cannot recall the reference) that vegetable oil is preferred to avoid long term problems. This was surprising to me after decades of using olive oil, but live and learn.

Posted by: kerrydeare | June 1, 2017 9:20 AM    Report this comment

What about the issue of damage to the gaskets and fittings? I have read that virtually anything put into the bowl (except, oddly, olive oil) can warp or damage them. Having personally rebuilt or paid to have rebuilt my Jabsco toilets way too many times, I am fairly paranoid about this.

Posted by: sailoray | June 1, 2017 8:58 AM    Report this comment

What about the issue of damage to the gaskets and fittings? I have read that virtually anything put into the bowl (except, oddly, olive oil) can warp or damage them. Having personally rebuilt or paid to have rebuilt my Jabsco toilets way too many times, I am fairly paranoid about this.

Posted by: sailoray | June 1, 2017 8:58 AM    Report this comment

I have a 1974 O'Day 27 with the same original arrangement. The previous owner removed the head and replaced it with a PortaPotty. Works great! No holding tank issues. No problem finding a place to pump out. Just grab the bottom part and take it to your closest shore toilet and dump. Not a joyous occasion, but simple and problem free.

Posted by: DMendels | June 1, 2017 8:55 AM    Report this comment

Recently I purchased a 1970' sail boat where the head drain flows directly into the lake ... Is there a good fix for this ... I can't believe in this day and age the head can flow directly into the lake ... Any body else fixed his? And where did you get materials or kit to do it?

Posted by: A Ord | June 1, 2017 8:30 AM    Report this comment

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