Can You Flush Toilet Paper On A Boat? | Become A Cruiser

Can You Flush Toilet Paper On a Boat?

Can you flush toilet paper on a boat
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Why do so many boaters refuse to flush toilet paper? The question is, can you flush toilet paper on a boat

When a Problem That’s Not a Problem Gets a Disgusting Solution

(This is an opinion piece. Feel free to debate in the comments.)

A common question from new boat owners is, can you flush toilet paper on a boat? Before I get to the full answer I shall say this.

If I had told my wife that I wanted to pack up our modern suburban life to go and live on a boat. And that on the boat we would have to gather up our used toilet paper. Then store it in a bag behind the toilet door! I know for certain that I’d still be sitting in my office watching snowflakes fall outside the window!

What’s more, I could never imagine having guests come around for dinner and then telling them that if they did a ‘Number two’. The paper they used would have to be put in a bin along with some of our own most recently enjoyed toilet paper!

I’m sorry if you’re planning on becoming a used toilet paper hoarder on your boat. It’s a disgusting habit you don’t want to get into. It’s right up there with farting in an elevator or picking your nose in the supermarket. So the question is can you flush toilet paper on a boat?

Why is Not Flushing Toilet Paper On a Boat Treated As Law, Without Question?

A blanket ‘No you can not flush toilet paper down a boat toilet’ is an urban legend. Sure you could block the pipes. And that worries some. Sewage is disgusting and dealing with blocked pipes tops the list on the ‘Dirty Jobs’ scale. But does one blockage every six months, year, five years exceed the nastiness of bundling up and storing your own fecal matter laced paper on a daily basis?

My take is a firm no! I say this as our boat’s Director of Sanitation. I would rather occasionally unblock the sanitary system the day after a burrito eating festival. Then subject, my family to bundling up their dookie smeared paper after each sitting.

Yes You Can Flush Toilet Paper On a Boat

A Change In Protocol Is All That’s Required

If you are new to boating. And asking yourself ‘can you can flush toilet paper on a boat’? Why not follow our suggestions and see if your boat’s sanitary system will allow you to flush toilet paper. After all, being able to flush toilet paper on a boat even with the occasional clog is far more attractive than the alternative.

  1. Switch to single-ply toilet paper, that is if you can find it. Surprisingly single-ply toilet paper can be hard to find at times. If you cannot find a single-ply then the lightest two-ply will do. There is absolutely no need to spring for special chandlery, marine toilet paper. Just don’t buy Charmin Ultra Soft unless you wish to perfect your bowl unclogging technique.
  2. Learn not to bunch up paper into a tightwad. The looser the bundle the easier it is to flush.
  3. There is no need to flush once per wipe. Experiment a little. Start with say ten bundles of 4-6 squares and then flush. see what kind of a challenge your sanitary system can deal with. Adjust as required. leaving a little head/ safety room. We have manual Jabsco toilets and there is no maximum amount we can pump at once. That is provided the wads are not too bunched up! On electric toilets, you need to be a little more gentle on the system. The key is lots of water. Experiment and see what works for you.
  4. Once you’ve got some idea of what the protocol will be. Inform and educate the crew.

Things to Consider Before Flushing Toilet Paper on A Boat

First off it is best to start with a clean system. If you’ve just bought your boat. I’d highly recommend replacing all of the sanitary hoses with a good quality chemical resistant hose. Change them even if the last owner says the hoses were changed last year. A year of poor flushing can seriously lead to seriously reduced pipe diameters as urine crystals block the pipes.

Urine Chrystals Are The Enemy

Seawater reacts with urine and forms uric acid and various carbonate crystals. The longer the urine sits in the pipes the more crystals form. The more seawater that’s pumped through the system the less the urine solution concentration. Which equates to fewer crystals. If you’ve never seen the crystals they are tough. Think terracotta tile.

On our boat, I’ve seen improper flushing reduce a standard one and a half inch diameter sanitary hose to less than a half-inch diameter of usable pipe diameter in less than a year. This happened in our kid’s hull. Our daughter is notoriously bad with flushing extra water and my son is really not much better. They were complaining that the toilet was hard to flush.

I went in and tried it and it was ok, not great. I tried lubing it with some vegetable oil but no joy. I ended up pulling off the section of pipe from the toilet to the holding tank and I was shocked by what I saw! Surprisingly the pipe never blocked with toilet paper. It just had a seriously reduced diameter.

Don’t kid yourself that a little acid rinse once a year leaves you with clean pipes. We do a high acid vinegar soak and flush monthly and an acid soak and flush once every six months. After seeing the blockage on the kid’s side I immediately checked the hose on our side, it had the thinnest coating of sludge. Same pipe manufacturer, same cleaning regiment on the same boat. Just different flushing techniques. So if my little experiment highlights anything. The key to uric acid terracotta free pipes is tons of water.

Can You Flush Toilet Paper With an Electric Head

The good news is yes you can. However due to the much smaller pipe diameters coupled with the fact that most electric heads do not flush enough water through the system. The pipes connected to electric heads tend to become blocked with crystals quite quickly.

Once you have tested and seen what amount of paper is safe to flush down an electric boat toilet. Make sure you seriously up the number of flushes or the length of time you hold the bowl fill/ pump-out button down when flushing papers.

Not only will this prevent toilet paper from sitting in the lines where it can dry out and get hard which will result in a blockage. But you will keep your pipes clear and free of crystal blockages. Even if you choose not to flush toilet paper down an electric head, I would strongly suggest increasing the amount of water you put through the system after each flush to keep the crystals down.

What Cannot Be Flushed Down a Boat Toilet:

Other than toilet paper, I do agree with the adage that you can only flush what has been through your body down a marine head. The following should NEVER be flushed down a marine toilet:

  • Sanitary Pads, Tampons – also known as expanding mice. If a product had been designed to perfectly block a marine sanitation hose they could not have come up with anything nearly as good as a Tampon.
  • Paper towel, shop towel, Bounty – Toilet paper is designed to be flushed and starts breaking down on contact with water. Paper towel on the other hand is designed to stay together when wet.
  • Dental Floss
  • Petroleum oils – not only are these bad for the environment but they will destroy various components in the sanitary system.
  • Bits of Paper
  • Make-up wipes, Baby wipes, etc. These are made of mostly plastic and not paper. Not only will the block your marine toilet but wipes should never go into the ocean.

Really anything other than toilet paper should not be flushed down a boat toilet.

Can You Flush Toilet Paper on a Boat?

The Marine Head Manufacturers Say, Yes?

Dealing with Boat Toilet Blockages




Step 1 Stop pumping!

The Moment you suspect a blockage stop pumping. If you have an electric pump that cannot be turned off at the bowl flick the breaker to turn it off. Electrical or mechanical. Pumping only makes the situation worse.

You can turn a quick two-minute retrieval into a multi-hour project. Admit defeat! Pumping more water will not make the situation better. Not only are you going to make the blockage more solid but you’re going to have to deal with a greater amount of contaminated sewage water.

Make sure your guests are aware of the need to stop pumping at the first suspicion of a blockage.

Now for the good news. Provided you stopped pumping right away. Most toilet blockages on a boat are relatively easy to deal with. To learn how to unblock a toilet on a boat please see my post on unblocking a marine toilet.

Can you flush toilet paper on a boat
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Hi, I’m Nic! Our Family of four have been out cruising since 2016. We have sailed about 15,000nm, almost halfway around the world. We sold everything, took the leap of faith, and bought a 10-year-old Lagoon 380 ex-charter catamaran. We’ve fixed every system on the boat, often more than once. Cruising has been such a wonderful, positive experience for our family that I want to share my tips to help you Become a Cruiser.

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4 thoughts on “Can You Flush Toilet Paper On a Boat?”

  1. Paper can block the holding tank itself. I had to find a safe harbour in heavy weather because my kids couldn’t use the toilet, then jury-rig a manual pump to empty a full 100L holding tank into jerry cans and carry them all 200yds to empty them. Then I spent the final day of my holiday dismantling unblocking and rebuilding the holding-tank to through hull section of the system. In theory, you can flush paper, but in practice not all guests or children have as much understanding of the rules, or are as invested in following them as the one who has to fix it, so no paper is easier.

    1. Thanks for your comment, Charlie.
      Sorry to hear about your ‘shitty’ experience. Indeed paper can block a holding tank more often than not the route cause of the blockage is calcium deposits that have fallen into the bottom of the tank that ends up being like fish tank gravel. Making it impossible to flush any solids through the tank. Clean out the tank completely and generally, toilet paper isn’t a problem. Take a look at my post on ‘How to Unblock a Toilet on a Boat‘ which covers unblocking a holding tank for more info.

  2. While I can’t claim thousands of miles I do regular cruises with true newbies (as in ‘never seen a sailing boat up close’) with all associated issues. Upside: The guests are willing to learn and listen (mostly…). Head regimen: Listen to the message, follow the message and don’t fix it without instructions. Worked reasonably well so far. Biggest headache to date: The tampon box ‘fell’, little torpedoes all over, followed by ‘search & rescue’ mission (yes, crawling tight spaces behind everything…). The last one found its way into the bilge pump and only ‘located itself’ when the bilge pump didn’t turn off… Pesky to remove but a reasonably clean job. I’ve had a blocked black water tank through hull – by courtesy of previous charter guests – which could luckily be freed up by plugging the vent and pressurizing with fresh water. Unfortunately the contents went into the marina… Performed by charter company personnel. My experience to date: I don’t want used toilet paper in my trash. Toilet paper used judiciously is ok – message says ‘flush profusely – then flush again’. Standing instructions: flush, fill the bowl, drain, fill again, drain – irrespective of #1 or #2. And any (technical…) observations are welcome! I do daily checks of all heads and toss in a teaspoon of olive oil – worked well so far. Also in the message: Heads don’t block themselves and that blocked head just cost you $200. I’m told the best way to stop that crystalline growth is fresh water flush – but that’s a whole new headache before even considering all that lovely fresh water down the toilet…

    1. Thanks for the comments, Eric. You are so right that heads don’t block themselves. When we have guests and we discuss the head and flushing we make it very clear that if something doesn’t feel right when flushing stop immediately. It is easier to deal with it before it becomes a problem. We don’t use freshwater but pump a lot of seawater which works well enough as long as you pump a lot. Adding a bit of olive oil to the toilet also works really well. I’m glad those tampons didn’t cause too much of a problem.

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