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MV Wanderlust · 22-09-2016, 16:06

Admittedly, I'm better with electrical than plumbing so help me understand this please.

The forward head is saltwater and has an electric flush. There's the head... Then on the wall is a green button that you push to flush. When you push it, a pump activates beneath an access panel. The pump is connected to a through-hull fitting, pulls saltwater through, and pumps it into the head beneath the rim. While holding down the flush button, a valve under the head apparently opens and the contents, including the saltwater, are pumped into the holding tank. Seems simple and straightforward.

The freshwater line that feeds the shower is right next to the saltwater through-hull line going to the head pump. Seems like I should be able to

Close the through-hull

Remove the hose going from the through-hull to the pump

(Cap the through-hull fitting as an extra precaution)

Install a tee-fitting on the freshwater line going to the shower

Connect the tee-fitting to the head pump

and...presto... the head would be freshwater.

This is a boat so it can't be that simple. There must be something I'm missing. Can someone who has done the conversion please explain why this won't work and what else would be needed?

On an unrelated side note: How do I set up the profile options to display the Vessel Name? Right now it is added to the Make and Model.

Thanks for any help you can give.

John

**StuM** · 22-09-2016, 16:18

Assuming your freshwater system has a pressure pump, you are now connecting pressurised water to the inlet of your pump. Depending on the type of head pump, that may mean that the water will flow continuously into the head.

Effectively, you are connecting your freshwater (drinking water) system to the bowl of your head. Hope you never get any backflow

**a64pilot** · 22-09-2016, 16:33

Couple of ways
Install a dedicated tank to hold the water to flush
Install a head meant to connect to your fresh water supply and has of course built in safeguards (best answer,in my opinion)
Hook your head to the sink bowl drain, fill sink before each flush.

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MV Wanderlust · 22-09-2016, 16:44

Interesting.

This YouTube video has an interesting approach:

https://www.youtube.com/watch?v=Vmm5KUT8sQ8

. It's 9 minutes long. Essentially, it involves installing a solenoid on a freshwater hose connected to the head. Pressing a switch fills the bowl with freshwater. Pressing the flush button then flushes it. The solenoid prevents back flush, presumably.

SV DestinyAscen · 22-09-2016, 16:58

Unless your head is speced appropriately, bacterial migration may eventually work it's way and contaminant your water.

River Cruiser · 22-09-2016, 22:08

You always want to drink upstream of the herd. No way I would plumb my potable water supply into the waste system.

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MV Wanderlust · 23-09-2016, 06:10

Okay, thanks. Good advice from all. The information here and in other forums has convinced me this is not a good idea. A brand new, freshwater head runs a little over $400. Seems worth it to avoid the risks. Appreciate the insight. We're still learning.

sailingforfun · 23-09-2016, 09:03

After market, Yacht Concepts in La Rochelle, on my request, installed the option of running salt or fresh water through my heads. Under each sink is a clearly marked lever and with the turn of a handle I can switch from fresh to salt water. I have had no issues to date.

We run fresh water while in marinas and when away for long periods. We use salt water when at sea.

I'm not mechanically inclined, so I can't answer exactly what they did, but they did it.

HopCar · 23-09-2016, 11:43

Depending on your current toilet, you may be able to save a few bucks by getting a Raritan Sea Era conversion kit. This allows you to reuse your bowl. No point in buying a new one if you don't have to. I sell the 162LF01201 kit for $398.95.
Replace your electric or manual toilet economically

Peggie Hall can tell you how to safely make this toilet work on either pressurized fresh water or raw water. You should buy her book. It's available in digital format on Amazon.

Sailingforfun, It's easy to do that but if it isn't done right, there is a danger of contaminating your drinking water. The danger is small but it has severe consequences if it happens.

seasick · 23-09-2016, 16:05

In my opinion if you want to flush your head with fresh water, lock through to a lake or sail up a river. No matter your tank capacity or your ability to make it, there is seldom enough for flushing it down the toilet.

**Lepke** · 23-09-2016, 20:32

You need a siphon break between the toilet and freshwater system. Just like new houses have them on garden hose faucets. When the FW system is shut down and drained, it can siphon the water from the toilet unless there is a siphon breaker in line.
Also, marine toilets built for salt water are not concerned with how much water they use per flush.

donradcliffe · 23-09-2016, 21:20

Quote:

Originally Posted by River Cruiser

You always want to drink upstream of the herd. No way I would plumb my potable water supply into the waste system.

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and just how is your house plumbed up??

**Dockhead** · 24-09-2016, 01:57

Quote:

Originally Posted by donradcliffe

and just how is your house plumbed up??

That's the point. The toilets in your house have tanks between fresh water supply and the bowl, and no way to backflow. Fresh water is poured into the tank.

Marine toilets don't have tanks, so using fresh water requires some engineering to be really safe. I would never attempt a home-made solution, myself.