Head inlet teed into sink drain, but…

[Pepijn]

Hi, we recently had issues with our aft head holding tank (pinhole leakages, smelly hoses, etc). Removed the holding tank for cleaning/repair, replaced old for new Jabsco toilet and will replace all hoses.

Since we will have a watermaker soon I am planning to tee in the head inlet to the sink drain and use freshwater to flush. This will free up a seacock for the watermaker.

Since I don’t want to open and close the sink seacock everytime I use the head I am contemplating to leave it close all the time. This means that after using the head the soapy water from washing hands (and perhaps washed down toothpaste from guests so now and then) will end up in the holding tank.

Any specific objections against this?

[alamoana]

Sounds like a great idea! Good luck

[sailorboy1]

Originally Posted by Pepijn

Any specific objections against this?

You are connecting the watermaker supply to old head supply not to the sink drain line right?

[Pepijn]

Not the sink drain no. Too high: near or at waterline. I will use the old head inlet for the watermaker.

[peghall]

using gray water to flush any toilet is a bad idea because soap scum, body oils, toothpaste etc can build up on parts in toilet pumps, causing problems.



But it's not necessary to use fresh water from the sink for every flush.Tee the toilet intake line into the sink drain line below the waterline...as close to the thru-hull as possible. Flush normally using sea water, switching to CLEAN fresh sink water to rinse all the sea water out the system before the boat will sit or if picking up some skanky sea water makes it necessary to rinse it out of the system immediately. Then you just close the sink drain thru-hull, fill the sink with clean fresh water, flush the toilet to rinse out the ENTIRE system...intake line, pump, channel in the rim of the bowl AND the toilet discharge line.


Doing it this way gives you the best of both worlds...you eliminate sea water odor problems and odors without having to sacrifice but a little of your fresh water for toilet flushing.


-Peggie

[ggray]

This is how I re-plumbed my sink drains years ago, based on Peggie's advice.

We have had no issue with soap, etc. fouling the head parts, but perhaps we don't use much soap!

Whatever, what Peggie says about a final flush with fresh water is helpful.

Plumbing the intake and sink drain together also makes it easy to winterize the head. And if you find yourself briefly living on board while hauled out, the head can still work. To the holding tank of course!

[Pepijn]

Thanks for the great advices! We will connect the head to the sink outlet. But as Peggy writes we will regularly do a freshwater flush. As liveaboards I will make it a weekly routine.

[Pepijn]

Thanks for the great advices! We will connect the head to the sink outlet. But as Peggy writes we will regularly do a freshwater flush. As liveaboards I will make it a frequent routine.

[Fore and Aft]

We have our toilet teed into the sink outlet as well. Great for us since we beach our boat all the time. Never had a problem in 6 years.
Cheers

[bstruebing]

So no trap? Does is stink? How do we prevent holding tank air coming up the sink when dumping the tank?

[peghall]

You're only teeing the toilet's flush water INTAKE line into the sink drain line. "Air" or anything else from the holding tank can only come into the toilet via the toilet's DISCHARGE line. To be able to bring in any flush water, the tee must be installed below the waterline...and btw, this only works if the sink drain thru-hull is below the waterline and on the same side of the keel as the toilet. Any odor in the sink from the drain line would be from something stinky in the sink that went down the drain.


--Peggie

[Wandering1]

Our boat has the toilet intake pipe and sink waste pipe combined in a bronze tee at the seacock. The boat is 44 years old and it has been built like this. The system works really well. By combining the pipes with a tee after the seacock, you can leave the seacock open and the sink waste discharges to the sea and the toilet intake pulls from the sea. Once the seacock is closed, you can pump toilet inlet water from the wash hand basin. This is perfect for when you want to leave the boat as you can pump fresh water into the toilet bowl.

[peghall]

Is there a trap in your head sink drain now? It would be highly unlikely! You'd only be teeing the toilet's flush water INTAKE line into the sink drain...the toilet PULLS seawater in via the sink drain thru-hull.

I first heard of teeing the toilet intake line into the head sink drain line from a Tartan owner. in the mid-90s....Tartan used to plumb their boats this way to eliminate a thru-hull. I thought i was a such great idea that I began recommending it as the best way eliminate sea water odor in the head from the dead and decaying micro--and sometimes not-so-micro animal and vegetable sea life left sitting the head intake while the boat sits. Just pouring water into the bowl only rinses out the toilet discharge line, it doesn't recirculate--and you wouldn't want it to!--through the intake line, pump and the channel in the rim of the bowl. A sinkful of clean water flushed through the toilet does.
You can flush with fresh from the sink every time or only use it to rinse the seawater out of the entire system before the boat will sit or any other time you feel the need to do so.

I do recommend that you keep a plug in the sink except when using it 'cuz when the boat is underway and heeled to the side the sink drain thru-hull is on, it can turn the sink drain into a fountain!


--Peggie

[Wandering1]

Originally Posted by peghall

Is there a trap in your head sink drain now? It would be highly unlikely! You'd only be teeing the toilet's flush water INTAKE line into the sink drain...the toilet PULLS seawater in via the sink drain thru-hull.

I first heard of teeing the toilet intake line into the head sink drain line from a Tartan owner. in the mid-90s....Tartan used to plumb their boats this way to eliminate a thru-hull. I thought i was a such great idea that I began recommending it as the best way eliminate sea water odor in the head from the dead and decaying micro--and sometimes not-so-micro animal and vegetable sea life left sitting the head intake while the boat sits. Just pouring water into the bowl only rinses out the toilet discharge line, it doesn't recirculate--and you wouldn't want it to!--through the intake line, pump and the channel in the rim of the bowl. A sinkful of clean water flushed through the toilet does.
You can flush with fresh from the sink every time or only use it to rinse the seawater out of the entire system before the boat will sit or any other time you feel the need to do so.

I do recommend that you keep a plug in the sink except when using it 'cuz when the boat is underway and heeled to the side the sink drain thru-hull is on, it can turn the sink drain into a fountain!


--Peggie

My Van de Stadt Trintella 44 had this as standard in 1980. Its been around a long time