Fresh water flush - separate tank

Have a manual toilet which currently uses seawater. Thinking of changing it to a fresh water flush. Complication is that I would like to install a separate water tank (3 gallons) so that the toilet is not connected to the drinking water system. The separate tank would be above the level of the toilet pump so that gravity would assist the pump in the same way that the sea water pressure applies.

In addition the separate tank would allow me to use rain water as we have an abundant amount of that.

Anyone done anything similar? Any thoughts?

I changed out the old SW head to a dedicated FW flush head several years ago, would not go back to SW again.

Raritan Marine Elegance Toilet

Your idea seem solid and should work just fine. Have a way to easily refill the tank from an on board supply while underway.

The Admiral was very pleased with the lack of smell using FW and I like the lower maintiance aspect.

I don't know about adding a tank, but the way I did it was:

1 Remove the hose that goes from the hand pump to the back of the toilet bowl.

2 Run a new hose from the hand pump to tie into the holding tank vent line. This allows the pump to operate.

3 Set the selector switch to empty and then remove the knob.

4 Run a new fresh water line from the side of the vanity to the back of the toilet bowl. There is a 1/4 turn valve on the side of the vanity.

The valve is about a foot above the toilet bowl. When you turn the valve pressurised fresh water flushes the bowl. When you shut off the valve the water in the line empties into the bowl and you end up with the line between the valve and the bowl empty. You then empty the bowl in the normal way.

We did this two years ago and consider it to be one of the best changes we have made to the boat. No more head odors and the pressurised water rinses the bowl much better.

I would just plumb into the existing water supply if you're installing a head that is made to use fresh water. They are designed not to contaminate the fresh water supply. Adding a separate pump and tank plus the plumbing and then having to fill the tank sounds complicated.

The freshwater input is separate from the output to the holding tank. Your toilet at home won't contaminate your freshwater system, a boat system is really no different.

I too would just use the house water system rather than complicate things by adding another system. If you are changing to toilets designed to use fresh water, then back flow protection will be built in. If you will be using your existing toilets, the the addition of a check valve will address your concern, and a valid concern it is.

I can hear Peggy walking toward her computer.

BlueYonder said:

The freshwater input is separate from the output to the holding tank. Your toilet at home won't contaminate your freshwater system, a boat system is really no different.

Click to expand...

Totally not true, and this advice can cause illness.

Research the differences please.

Do NOT connect the raw water input from your std. head to the fresh water supply on your boat!!

If the system you have at home is the same as your boat then one of your systems is quite a bit different then the rest of us. They are not at all the same.

Calling the Head Mistress, come in please.

There are several different styles of preventing backflow contamination usually depending upon the potential risks involved. What is referred to as an air gap is the typical style used in "home" toilet plumbing. This is achieved in the tank of your home toilet where the water line coming into the tank more or less sprays water down into the tank and then shuts off at a predetermined level. The water line never touches (thus "air gap") the water in the tank. A single swing check valve is another way but does not completely stop potential contamination in that the swinging gate does come in contact with water on both sides of the valve but does prevent the entire downstream water from returning into the supply line during a decrease in pressure type situation. A marine style toilet will have an air-gap loop type supply that is built to perform like your home toilet but without the tank.

SCOTTEDAVIS said:

Totally not true, and this advice can cause illness.

Research the differences please.

Do NOT connect the raw water input from your std. head to the fresh water supply on your boat!!

If the system you have at home is the same as your boat then one of your systems is quite a bit different then the rest of us. They are not at all the same.

Calling the Head Mistress, come in please.

Click to expand...

All of the major head manufacturers have fresh water flush heads that connect to the on board system. They use a vacuum breaker valve that is positioned above the bowl of the head. An owner can do exactly the same thing with the correct piece of equipment. Raritan now sells a kit to do exactly that. I used a combination vacuum breaker and solenoid valve from Jabsco when I converted both heads on our boat. Zero issues with contamination If done correctly. This is discussed in many threads in the archives. Raritan used to have a "how to" on their web site until they decided to sell a kit instead. No problem with installing an extra tank, but it really isn't necessary.

I know about the properly designed systems, I have one as I stated.

Read what I said, I clearly refered to a sandard head designed for raw water that was then hooked up to the boats fresh water supply being wrong. Using a kit or buying a fresh water head is not what was proposed thus prompting my response.

The marine head not the same as a dirt home head in any way, plumbing wise.

Couple of things - just my situation. I am not buying a new toilet. Using my 16 year old manual which serves me well.

Prefer not to have to trust any add on check valve to avoid contamination of the drinking water.

Prefer not to use drinking water for this purpose. All drinking water is from a watermaker. It is the rain water supply I intend to use. I have now added a runoff collecting system to the top deck and it supplies rain water for deck washing and with this addition the toilet. Just my preference.

Those devices are designed to connect to existing fresh water system and have decent check valve and solenoid valve ( at least my Raritan does). If it made you feel better, install another check in line.

Unless you're super attentive to keeping you're existing fresh water tanks and transport lines sanitized, there's probably more of a risk from getting the nasties from your tanks or lines, than the risk of back feeding from the waste side of a toilet into the fresh water side of the supply.

Conall

During our re-fit we put in an electric toilet and it's worked perfectly ever since. Always been plumed to our house water tanks.

skidgear said:

All of the major head manufacturers have fresh water flush heads that connect to the on board system. They use a vacuum breaker valve that is positioned above the bowl of the head. An owner can do exactly the same thing with the correct piece of equipment. Raritan now sells a kit to do exactly that. I used a combination vacuum breaker and solenoid valve from Jabsco when I converted both heads on our boat. Zero issues with contamination If done correctly. This is discussed in many threads in the archives. Raritan used to have a "how to" on their web site until they decided to sell a kit instead. No problem with installing an extra tank, but it really isn't necessary.

Click to expand...

How true.....

Look at the exploded diagram of any RV toilet and see the simple, inexpensive vacuum breaker is all that is there past some solenoid or foot flush mechanism.

$35 http://www.americanrvcompany.com/Dometic-Toilets-RV-Model-301-Parts

I modified a manual and was told by the Experts....not to do it I would get sick....well no one aboard did for years.

Just the usual TF fear mongering about innovation.

Went back to salt water...as a liveaboard....the smell never has long enough to develop.

Bay Pelican said:

...The separate tank would be above the level of the toilet pump so that gravity would assist the pump in the same way that the sea water pressure applies...

Click to expand...

I remember from my sailboat days when some marine heads, that were below the water line, after use, a valve had to be turned so that seawater didn't back fill the bowl and flood the boat. A consideration if you mount the tank higher than the bowl but you'd only potentially have 3 gallons or less of fresh water. Just a thought.

Ye gods and little fishes!!

BlueYonder said:

The freshwater input is separate from the output to the holding tank. Your toilet at home won't contaminate your freshwater system, a boat system is really no different.

Click to expand...

That's not true. 1. The water in the fresh water plumbing in your house is always pressurized. Water onboard only remains pressurized as long as the pump remains on. Pressurization prevents backflow and bacteria migration.

2. The fresh water line in your house is connected to a flush water tank that is above the bowl. The bowl is fed by gravity...no contact with the fresh water plumbing. Y'all want to connect the line to the back of the bowl or the toilet pump that has a line that goes directly to the bowl.

3. When the boat's water pump is off, the fresh water system isn't pressurized, leaving bacteria from bowl--and from READYTOGO's holding tank vent line are free to migrate in any direction into your fresh water plumbing. (What were you THINKING??? Bacteria laden gasses from the tank are bad enough....Did it ever occur to you that a holding tank overflow out the vent would put sewage into the head intake line...That's connected to your your potable water supply???? You're playing Russian roulette with your own health and that of every passenger or crew that's ever onboard...and so far you've been lucky)

There's a bit more to toilets designed to use pressurized fresh water than just a check valve...you'd need a back flow preventer (check valve) siphon check valve...if the toilet is electric, a solenoid valve...

There's a much easier way that's SAFE: replace the toilet with one designed to use pressurized fresh water...and there's one for just about every budget:

If you want to stay with a manual toilet, you can...Last year Raritan introduced the first MANUAL toilet designed to use pressurized fresh water--the "Fresh Head" Fresh Head It's available as either a complete toilet or a "conversion"--everything south of the bowl, which allows you to re-use your existing bowl, seat and lid...any bowl that has a + mounting bolt pattern will fit it.

Or swap out your existing raw water electric toilet for one designed to use pressurized fresh water...Jabsco offers their 37xxxx series toilet in both sea water and fresh water versions, as both complete toilets or "conversions" (everything south of the bowl...any bowl that has a + mounting bolt pattern will fit it). Or for about the same price, you can upgrade to a Raritan SeaEra QC SeaEra QC (complete toilet or "conversion" SeaEra Conversion Kit

None of these should cost you much more than adding a tank and all the plumbing needed to add a separate flush water tank...which, btw, CG require that it have it's own separate fill and separate vent line...it cannot share ANY plumbing or even a vent with the potable water supply. If you've gotten away with it--or any of your other cockeyed Rube Goldberg modifications, it's only because the inspectors aren't aware of the reg...I can name several other regs 90% of 'em don't know about either.

The Raritan Marine Elegance Marne Elegance Promo Sheet is the top-rated all china "throne" available--including the optional 4 option "Smart Flush" Panel"--for about $600 if you know where to shop.

A 3-option flush panel is also available--a rocker switch that lets you add water to the bowl, dry flush or both similtaneously is also available...this one will also work on the fresh water version (ONLY the fresh water version) of the SeaEra.

Bottom line: you have only three choices that don't endanger your health that of everyone who's ever aboard your boats:
1. Continue to use raw water to flush your sea water toilet
2. Add a separate flush water tank that has no connection whatever to the fresh water tank.
3. Swap out the toilet for one that's designed by the mfr to use onboard pressurized fresh water.

That's my $.02 worth...you did ask.

From Head Mistress

"3. When the boat's water pump is off, the fresh water system isn't pressurized, leaving bacteria from bowl--and from READYTOGO's holding tank vent line are free to migrate in any direction into your fresh water plumbing. (What were you THINKING??? Bacteria laden gasses from the tank are bad enough....Did it ever occur to you that a holding tank overflow out the vent would put sewage into the head intake line...That's connected to your your potable water supply???? You're playing Russian roulette with your own health and that of every passenger or crew that's ever onboard...and so far you've been lucky)"



I am not sure you understand what I did. The hose we are talking about goes from the tank vent to the hand pump. It in no way connects to the fresh water lines. The only thing the pump now does is empty the bowl. The fresh water line attaches to the back top of the bowl. Even if you completely filled up the bowl to overflowing it could not enter the fresh water line.

I understand exactly what you did...you ran a line from toilet pump to the tank vent. So in the event of a tank overflow out the vent, waste will go into the line that goes to the toilet pump...the toilet pump is connected to the bowl to which you've also connected the potable water system..bacteria in the pump WILL contaminate the potable water system. But it doesn't take a vent line full of waste to pollute the system...gasses from the tank are full of bacteria...

Why do you think CG regs prohibit ANY shared plumbing, not even a vent, between the potable water supply and a flush water or gray water tank, or why gray water and black water tank systems must be totally separate? Because the risk is real! Just connecting the potable water supply to the toilet bowl puts the potable water supply at risk...You've not only created a system that shares plumbing with the toilet, you've created one that shares it with the holding tank!

The way that it is plumbed works just like the Raritan vacum breaker. Either you don't understand how I have it plumbed or I just have to respectfully disagree.

It may work the same way, but Raritan has never connected a vacuum breaker to the holding tank vent.

Btw...CG regs also require that all holding tanks be vented to the outside of the vessel, because a)methane is flamable, and b) other anaerobic gasses--sulfur dioxide and hydrogen sulfide--are toxic, even lethal in sufficient quantity. By tapping a "vacuum breaker" into the tank vent, you've created an escape for those gasses inside the boat.

I know you aren't gonna change a thing...you're too determined to believe that you haven't done anything wrong to be swayed by contradictory information. The best I can hope to do here is prevent anyone else from making the same mistakes.

Peggy, by your coment about about tapping a vacum breaker into the holding tank vent you obviously do not understand how the system is plumbed. lf the problem is the holding tank vent being hooked to the toilet pump is the fly in the ontment that could easily be changed to have its own through hull vent. The only reason for it is to allow the pump to function. If what used to be the outflow of water to the bowl is simply capped off the piston in the pump can not operate. Thus it has to be left open. The easiest place was to connect it to the vent hose for the tank, but as said before it could utilize its own through hole.

Bay Pelican said:

Have a mainual toilet which currently uses seawater. Thinking of changing it to a fresh water flush. Complication is that I would like to install a separate water tank (3 gallons) so that the toilet is not connected to the drinking water system. The separate tank would be above the level of the toilet pump so that gravity would assist the pump in the same way that the sea water pressure applies.

In addition the separate tank would allow me to use rain water as we have an abundant amount of that.

Anyone done anything similar? Any thoughts?

Click to expand...

If it's a Raritan, you might look at their Part number2500RFK...listed in Defender catalogue as Fresh Head Retrofit kit, item 503404. Suspect Jabsco has something similar. But it ain't rocket science and you can safely create your own kit from components if you wish to hook up to the fresh water supply system.

Bay Pelican said:

It is the rain water supply I intend to use. I have now added a runoff collecting system to the top deck and it supplies rain water for deck washing and with this addition the toilet. Just my preference.

Click to expand...

So where does your rainwater collect? If it's a tank why not simply add a pump (on a switch) to take from said tank and fill head? Then you'd only have to run a hose so I'm thinking the plumbing would be simpler.

Rainwater tank
to
pump (12 volt)
to
head

Unless I'm missing something I see no reason to add a 3-gallon tank to the head. That'd be messy and take up space in that compartment. You have a pump for the spray down so adding a tee with a spigot or valve can't be complicated.

Do you use your rain collection system to wash down your anchor? If so what type of anchor are you using?

Ulysses-an anchor that only holds on rainy days.

The OP (Bay Pelican) has stated he wants to make a totally separate system, as well as stating his reasons...It seems to me that the system he is envisioning is in total compliance with the CG regs that Headmistress is pointing out. So, I'm curious, what is all the discussion about since it in no way answers the questions originally posted?

Not sure the USCG cares that deeply about uninspected boats.Just the discharge issues.

Just cheap options besides a separate tank.

Rigging a separate tank is easy and I am sure he can handle it...just providing info that may be helpful.

Greetings,
Mr. wy. "...what is all the discussion about since it in no way answers the questions originally posted?..." Ahhh, you miss the whole point of thread drift. Did you ever play the game of telephone when you were a kid? This is telephone on an adult (?) level.
Take a fr'intance... A newbie asks "Can anyone tell me how to replace my Jimpson hanger?" 341 posts later one member will be chastising another about where to anchor and why his/her type of anchor is the wrong one. Furthermore that piece of sh*t anchor should be placed on the restricted weapons list and the designer of said piece of garbage should be forced to listen to Barry Manilow songs whilst drinking Pabst Blue Ribbon beer in a Hungarian brothel.
Meanwhile, the original OP has sold his boat and asking the same question on an RV chat group.

AAAAAAAAahhhhhhhhhhhhhhhhhhhhh, Thanks RT...now I get it! Please forgive me, I'm still a newbie when it comes to this type of "adult" behavior. Don't worry, with the patience of people like you, I will learn..I WILL!