Stench when toilet is flushed

[HeatherAlyssa]

Good evening Trawler friends. I'm experiencing a horrible stench throughout the boat only after the toilet is flushed. Even with the holding tank slightly filled, there is no odor at all when I walk back in after a long day at work. This leads me to believe that the holding tank isn't leaking, and odors are not permeating from the sanitation hose. I only smell this after it is flushed. Is there a way to prevent this, or is this an indication of a problem

 

[gaston]

Had the same problem gave the tank a big dose of Sodium Percarbonate

 

[C.O.S.T.]

Sea water and crap in the outlet hose from the offending toilet can cause this. If it is from the holding tank it may be the vent is plugged.

 

[Comodave]

Get Peggie Hall's book and read it. It will explain almost everything about head systems.

 

[dhays]

Fresh water or raw water head?

My guess is a problem with your vent, that and a seriously sick holding tank.

 

[HeadMistress]

I wouldn't be too quick to rule out sanitation hoses. Flushing creates pressure on the hose walls that can push odor out of hoses that haven't permeated enough yet to stink all the time. Wet a clean rag in hot water, wring it out and wrap it around the lowest point in your toilet discharge hose...flush the toilet. When the rag has cooled, remove it and smell it. If the hose isn't a culprit, there will be no odor on the rag...if there is, your hoses have begun to permeate.

Other possibilities include odor out the tank vent when you flush that's making its way into the boat via an open window or hatch or a hose connection that's leaking only when there's pressure from flushing...an inspection port on the tank that has a cap in need of a new o-ring...

Odors are always strongest at their source. If your toilet uses sea water and the odor is strongest in the head, you may have sucked in some sea life that's died and decayed in the intake line and/or pump (The WORST I ever experienced was the remains of a baby octupus). You'd most likely see black flecks in the flush water coming from the rim of the bowl if that's happened. Or, if the joker valve in your toilet is waaaay overdue for replacement, it could just be odor from the tank escaping into the toilet. If so, that could also indicate a blocked tank vent, especially if you toilet has begun "burping" and...spitting up when you flush.

Start with those possibilities...if none of 'em pan out, we'll brainstorm it till we find the source and eliminate it.

 

[BruceK]

.. I'm experiencing a horrible stench throughout the boat only after the toilet is flushed.

Sounds serious, I find the stench goes away after I flush.

 

[roberttigar]

Smelly head

If the smell is coming from the holding tank, the hoses are good. no clamps are loose and the vent is clear...try a vent filter. They are avail to purchase. ..about $80. I made one using a piece of pvc pipe and activated charcoal...cost about $15. Requires refilling once a year
Bob

 

[ranger58sb]

Other possibilities include odor out the tank vent when you flush that's making its way into the boat via an open window or hatch..

Or maybe through an engine room vent and from there into the main cabin...

HA, I'd guess this is the maybe easiest to diagnose, and fix if necessary. Stand outside the vent while somebody flushes. If there's a vent filter in your system, and the flush knocks you into the water anyway... then it could be as simple as replacing the filter.

-Chris

 

[rwidman]

Perhaps the smell is from what you put in the toilet before you flushed it.

Seriously, if it's a raw water flush head, I'm going with the dead sea life that's been drawn in when you flush and has dried out and died in the intake hose and the water passages in the head itself. One symptom of this is that the smell is the worst the first time you flush the head after it's been sitting for days or weeks and the smell gets less intense as you continue flushing that day and the next.

A clogged vent has other symptoms like not being able to fully empty the holding tank (it's possible to collapse a holding tank if the vent is clogged and the pumpout is strong enough).

 

[tallswede]

Most likely cause is dead sea creatures {tiny plankton etc) in the flush water. Mine does this every time I flush after the boat has been sitting unused. If I'm out cruising and using the heads regularly the smell stops until the boat sits unused again. I'm contemplating setting up a freshwater flush line for each head to use when I know the boat will sit unused for a few days.

Kevin

 

[dhays]

We don't yet know if Heather has a raw water or fresh water head.

 

[HeatherAlyssa]

I'm just catching up on the replies. I knew there would be a couple of funny comments. Ha ha. It is a raw water system. I knew it was only a matter of time before I had to got close and personal with my waste. [emoji30] I'm going to take a little time to process this.

 

[rwidman]

Most likely cause is dead sea creatures {tiny plankton etc) in the flush water. Mine does this every time I flush after the boat has been sitting unused. If I'm out cruising and using the heads regularly the smell stops until the boat sits unused again. I'm contemplating setting up a freshwater flush line for each head to use when I know the boat will sit unused for a few days.

Kevin

You need to be very careful with this. Raw water heads cannot be safely connected to your boat's potable water system. There's a serious danger of cross connection between the sewage side and the water you drink. A "check valve" is not sufficient to prevent this.

You would need something like a separate water tank with no connection to your potable water tanks. You could fill this tank with a hose and then install a valve to the intake of your raw water head to where you draw water from the water your boat floats in or the water from the tank.

Or, you could install a filter on the raw water line to keep the sea life out in the first place.

 

[HeadMistress]

Most likely cause is dead sea creatures {tiny plankton etc) in the flush water. Mine does this every time I flush after the boat has been sitting unused. If I'm out cruising and using the heads regularly the smell stops until the boat sits unused again.

Odor from sea water left to sit and stagnate goes away after the first use when you come back aboard flushes it all out of the system. He said he experiences it every time the toilet is flushed.

I'm contemplating setting up a freshwater flush line for each head to use when I know the boat will sit unused for a few days.

I hope you're not considering connecting your toilet to the fresh water plumbing, Kevin. However there is a safe way to supply fresh water to a sea water toilet without doing that: Tee a y-valve into your head sink drain line and also one in your toilet intake line as close to the intake thru-hull as possible and still be accessible. To rinse the sea water out toilet and all its plumbing, close the toilet intake thru-hull, turn the y-valves to direct the flow from the sink to the toilet intake line, fill the sink with clean fresh water...flushing the toilet will pull the water out of the sink, rinsing out the whole system--intake line, pump, channel in the rim of the bowl and the toilet discharge line. Just pouring water into the bowl and flushing only rinses out the toilet discharge line.

It's easier re-plumb if your head sink drain thru-hull is below-waterline (which it is on most sailboats, but not common on powerboats): just re-route the toilet intake line to tee into the head sink drain line as close to the thru-hull as possible (this frees up a thru-hull for other uses, btw)...it needs to be below waterline. Flush normally with sea water till you're ready to close up the boat. Then close the the thru-hull, fill the sink with clean water...flush the toilet. Because the seacock is closed the toilet will pull the water out of the sink, rinsing out the whole system.

 

[dhays]

Odor from sea water left to sit and stagnate goes away after the first use when you come back aboard flushes it all out of the system. He said he experiences it every time the toilet is flushed.

Not sure about that. In reviewing HeatherAlyssa's post it wasn't clear if this was every flush or not.

Our sailboats had raw water flushing. On our last sailboat the aft head had a very long intake line from the thru hull to the head. This made very a very smelly first flush.

BTW, on a prior sailboat we did just as Peggy suggested, plumb a Y valve in the drain of the sink and connect that to the raw water intake line to the head. Last flush before leaving the boat, we filled the sink with fresh water, adjusted the valves, and gave the head a fresh water flush. It worked great.

 

[Searios]

Watermark Approved valves

This Australian valve system could be fitted so that both fresh water and seawater can be used.

https://www.irrigationwarehouse.com.au/prod125.htm

Maybe this valve system will prevent cross contamination since it's Watermark Approved.

 

[HeadMistress]

That's ok in a house because toilet flush water goes into a tank that then drains into the toilet bowl, but flush water goes directly into marine toilet bowls from either the sea water intake line or any line connected to the potable water supply. Toilets designed to use onboard pressurized fresh water have vacuum breakers, siphon breaks and backflow preventers built into them...sea water toilets do not.

 

[gaston]

Had the same problem gave the tank a big dose of Sodium Percarbonate

Up date week 2 and added another cup of Sodium Percarbonate to a 100liter tank .This is the first time in months without any smell

 

[Searios]

Peggy.

If one has a marine toilet with pressurised water as you described, then that valve system will be OK - or am I misunderstanding you?

 

[HeadMistress]

Peggy. If one has a marine toilet with pressurised water as you described, then that valve system will be OK - or am I misunderstanding you?

Only if the toilet also has a remote intake pump and a flush water inlet fitting that's totally separate from the pressurized flush water inlet.

That system is approved for household use because household toilets and marine toilets have almost nothing in common. Sea water toilet intake pumps PULL water into the toilet...toilets that use pressurized water don't have any intake pump...they just have a valve that opens the flush water line to allow water pressure to PUSH water into it, much the same as opening a sink faucet does. So without a remote intake pump to push sea water into a toilet that uses pressurized flush water, you won't get any sea water. If both sea water and fresh water share a single inlet fitting on the toilet, there's nothing to prevent sea water from contaminating the fresh water supply.

The Raritan Atlantes, Elegance and SeaEra QC are all fitted to allow both pressurized and sea water by adding the "sea fresh" option. The installation/operation instructions should give you a good idea of how it has to be plumbed.Raritan seafresh.pdf

Even if that contraption could work on a boat, wouldn't all those pipes and valves cost a fortune? Not to mention all the space it would need and accessibility?

 

[HeadMistress]

Gaston, While you may have found a way to temporarily eliminate odor, you're doing so by killing the bacteria in waste that's needed to breakdown solids and TP, which is critical to a trouble-free system. You want to work WITH nature, not against it to PREVENT odor occuring in the first place, and the key to that is oxygen....when organic matter breaks down aerobically it converts to CO2, which is odorless. It's only when it breaks down anaerobically (without oxygen) that it can generate hydrogen sulfide, sulfur dioxide--both stinky and highly toxic gasses-and methane which although flammable is odorless. Try flushing a couple of ounces of NoFlex Noflex Digestor into the tank every week. If that doesn't cure your odor problem, replace the the vent thru-hull with an open bulkhead thru-hull to allow more air exchange via the vent.

I suggest you also check out the link in my signature.

 

[Giggitoni]

Thank you, Peggy!

 

[HeadMistress]

Thank YOU! Also available in Kindle, btw.

 

[HeatherAlyssa]

Stop the presses. When I purchased my boat it came equipped with Peggy's book. I failed to read Page 35 on Electric toilets, Flushing electric toilets 101. I've been pressing the button for like a second at a pop. Maybe two Max to save on space in my holding tank. I think that's the issue. I'm going to Press the button longer from now on and see how that works.

 

[HeadMistress]

You have the first edition which had become so outdated that I was forced to write "The NEW updated, revised and expanded" 2nd edition, which was published last year. Title in my signature is a link to it.

However, flushing longer may or may not solve your problem. Does your toilet use sea water or pressurized fresh water? If it's a sea water toilet, do you have odor every time your flush or only the first use after the boat has been sitting? Is it definitely coming from the toilet or originating from elsewhere in the boat?

Failing to flush any toilet--manual or electric, sea water or fresh--long enough does leaves waste in the discharge line to "ripen" in the summer heat. So flushing longer will help, but if the joker valve (one way valve in the toilet discharge fitting) is worn out and no longer seals, odor from the inside of the hose and the can come back into the toilet.

Joker valves should should be replaced annually...or at least every two years. Even more important to change it annually in manual toilets..."Joker Valve 101" in the new book explains why.

Waste left to sit in the discharge hose also permeates hoses, which is why it's a good idea to flush at least a quart of clean water down the toilet (use a cup from the sink), even those that use fresh water, before the boat will sit.

 

[HeatherAlyssa]

I flushed the toilet for like 8 seconds, and then put my nose right in the toilet and left it there for a few seconds. Then I came back and did the same thing a minute later. It didn't smell at all. I was using quick flush bursts before today. I noticed after quick bursts, there was still a horrific odor. After using the new procedures, and I've done it a couple times today, I don't smell a thing. Before hand, it would smell like ... yeah. It's a salt water jabsco 37010-1090.

 

[dhays]

Sounds like you are smelling the dead sealife in the raw water line. I would be curious to know if you get the same smell on the first flush after the boat has been sitting unused for a week.

 

[Heron]

Recently had this issue.....Turned out to be a lot of stuff in the inline strainer to the head flush. Cleaned it out and all smell disappeared..

 

[goboatnow]

With regards to dead sea life smelling in the raw water intake - in other people's experience, how long does that take?

We have a manual Groco head plumbed with sea water that is only used to urinate. Our flush water starts to stink after about 6 hours. This doesn't seem right. It's been that way since we owned the boat (2 yrs). Cruising from SoCal to SE AK.

What have others experienced?