Fresh Water Leak

Aug 26, 2007
266
Hunter 41DS Ventura, California
My 41DS has developed a leak in the pressurized water system and I am at a loss as to how to identify the location. It only leaks into the bilge at a very slow rate and only when pressurized. The majority of the plumbing is difficult to inspect and I would prefer to determine the approximate location before removing floor panels to expose the plumbing. The tanks are surrounded by foam insulation so difficult to inspect but since they are vented, I don't think they are pressurized so I assume the leak is downstream from the pump.

I do have pool leak detecting dye so could isolate which tank was leaking if it was in fact a tank. The only procedure I can figure out is to turn off all the circuits from the main distribution manifold and turn them on one by one. This could take a long time since the leak is so slow(overnight to get the bilge water level high enough to turn on the small bilge pump). The pump will eventually turn on and cycle as it pumps out and bilge slowly refills. I live 200 miles from the boat so this process could take months.

It is probably wishful thinking that there is clever procedure to find the leak without tearing up all the flooring but one can only hope!

Any help greatly appreciated!
 

jviss

.
Feb 5, 2004
7,089
Tartan 3800 20 Westport, MA
That sucks. It can be very frustrating. What kind of plumbing have you, I mean, what kind of tubing, fittings, etc.?

I always thought that over-pressurizing it, perhaps just with air, and going around listening, might be a good troubleshooting approach.
 
Jan 4, 2006
7,012
Hunter 310 West Vancouver, B.C.
The pump will eventually turn on and cycle as it pumps out and bilge slowly refills.
No need to wait for the bilge pump to come on. Doesn't tell you where the water is coming from.

Clean and dry vertical and horizontal surfaces around the bilge. Tape paper towel down and observe which direction the water comes from. It's a start.

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Any leaks I've found in my potable system have always been associated with leaking tube fittings. Just sayin'.

(overnight to get the bilge water level high enough to turn on the small bilge pump).
If the leak will add enough water to fill the bilge enough to kick on the float switch, this is more that a just a drip.

You didn't give the year of your boat but I'm betting the floor boards are held down with screws into the ribs and stringers of the boat. They're not hard to remove. Put a few towels around the bilge getting the water and again try to identify the direction the water is coming from using the paper towels. Hell, use a large terry towel and hair dryer to dry wet sections of the hull interior and watch for water moving across the dry interior. From what you've described, this is a LARGE leak.

Being 200 miles away from your boat, you are going to have to stay on the boat until the problem is solved or spend the majority of your time driving and forth.

If you can pressurize small sections your piping ay one time, install a pressure gauge and check which section loses pressure.

I live 200 miles from the boat so this process could take months.
Or else you become so old you've forgotten why you're even on the boat.
 
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jviss

.
Feb 5, 2004
7,089
Tartan 3800 20 Westport, MA
If you can pressurize small sections your piping ay one time, install a pressure gauge and check which section loses pressure.
That's actually a pretty good idea. It's common in house plumbing to run a leakdown test on newly installed plumbing, required by code in many places.

The difficulty here is that it could be anything - a leaking tank, a leak on the pressurized side, and so forth. Isolating those could be a good first step.

1. fill the tanks and turn off the pump and depressurize the system, and then see if you lose water. You can also plug the tank vents and the hose to the pump and pressurize the tanks with a bicycle pump. If it doesn't hold pressure, your leak is on that side.

2. bypass the water heater, as it holds 6 to 10 gallons or so, and you can drain, and then fill the pressure side with pink antifreeze, or even just water with food coloring - a short tube from the jug of stuff to the input side of the pump. Then, after it's pressurized, go looking for the color.
 
Aug 26, 2007
266
Hunter 41DS Ventura, California
Lots of good ideas folks, thanks. It is a 2007 boat and the floorboards are screwed down- at least they ARE removable. Again, it only leaks when pressurized so shouldn't be a tank leak. Takes at least overnight to get 1 to 11/2 gallons of water in the bilge so more than a seep. It doesn't leak fast enough for the pump to cycle unless very rarely when everything is static but of course it does when the system is in use.. I'm going this week to see what I can find. Will follow up here when (hopefully ) I find the leak! Thanks again.
 
Jan 4, 2006
7,012
Hunter 310 West Vancouver, B.C.
Takes at least overnight to get 1 to 11/2 gallons of water in the bilge so more than a seep.
You're right, it's not a seep it's a torrent :facepalm:.

Surely you can see the deluge running across the interior of the hull under the floor boards. Tiny little relief crews (FEMA) may have already moved in for disaster relief down there under the floor boards.
 
Sep 24, 2018
3,066
Catalina 30 MKIII Chicago
They make UV dye for leak testing in houses. It's available at most hardware stores and is safe for drinking water. Requires a UV light. Most autoparts stores with a tool loaner program will have a light and UV enhancing glasses available to use for free. Most likely intended to detect AC leaks
 
Jan 11, 2014
12,273
Sabre 362 113 Fair Haven, NY
The only way you will find the leak is to start at the water pump and follow the plumbing inspecting every joint. The dyes aren't really helpful becuase where you see the water may not be where it is actually leaking. There is no easy quick way to do this. Get some knee pads, a good flashlight, and some paper towels and start looking. On an older boat it is more likely than not there is more than one leak. It took me a year to find all the leaks on my boat, including one that required a major disassembly to access. The solution was replacing the whole plumbing system with PEX.

Good Luck, it's no fun, but it has to be done.
 
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Feb 10, 2004
4,069
Hunter 40.5 Warwick, RI
I will throw in my 2 cents......
You began with the premise that you had a fresh water leak. Have you absolutely confirmed by tasting that the leak isn't salt water?
If you are 100% sure that it is a fresh water leak, then continue.....
If you are certain that the leak only occurs when the pump has pressurized the system, then it is reasonable to rule out the tanks, lines, and fittings up to the pump.
In my experience, leaks have always been at a fitting or a valve. So I would start by pressurizing the system and then systematically going to every fitting and valve that you have. Wipe the fittings with a paper towel and then test the joints with a tissue. Shake each joint gently while checking for a leak to be sure you don't have something intermittent.
If the leak(s) are not found, the next step would be to check all of the water line junctions. Those would be where a water line is tee'd to two different faucets. These tees are often hidden behind panels. If you have a layout of the water system for your boat, you may be some clues as to where to look.
Placing towels or tissues around the bilge to determine the direction of the leak flow can certainly help you zero in on the likely area first. But as was mentioned, water can leak from one spot and travel a circuitous path that could indicate an incorrect path.
A much less likely leak source could be a chaffed water line. Pray that you have been a good boy and that isn't the case.
 

Rick D

.
Jun 14, 2008
7,178
Hunter Legend 40.5 Shoreline Marina Long Beach CA
My 41DS has developed a leak in the pressurized water system and I am at a loss as to how to identify the location. It only leaks into the bilge at a very slow rate and only when pressurized. The majority of the plumbing is difficult to inspect and I would prefer to determine the approximate location before removing floor panels to expose the plumbing. The tanks are surrounded by foam insulation so difficult to inspect but since they are vented, I don't think they are pressurized so I assume the leak is downstream from the pump.

I do have pool leak detecting dye so could isolate which tank was leaking if it was in fact a tank. The only procedure I can figure out is to turn off all the circuits from the main distribution manifold and turn them on one by one. This could take a long time since the leak is so slow(overnight to get the bilge water level high enough to turn on the small bilge pump). The pump will eventually turn on and cycle as it pumps out and bilge slowly refills. I live 200 miles from the boat so this process could take months.

It is probably wishful thinking that there is clever procedure to find the leak without tearing up all the flooring but one can only hope!

Any help greatly appreciated!
FWIW, I chased a leak on our boat (40.5) for two years until I found it to be at the hook-up to the swim step shower. I re-sealed the joints but it leaked again a year later. I replaced the shower assembly and it leaked yet again in two years. I finally installed shut off valves on the lines leading to the shower, and all has been good. The interesting part was chasing this down. I was sure it was an aft rub rail leak and was from washing the boat or winter rain. The leak manifested itself far away from the source. and only when the water pump was on. Good luck!
 

jviss

.
Feb 5, 2004
7,089
Tartan 3800 20 Westport, MA
To repeat what I've asked before, in posst #2:
What kind of plumbing have you, I mean, what kind of tubing, fittings, etc.?
It's hard to help you without knowing.

If you decide to re-do all of the potable water plumbing, I highly recommend LLDPE tubing and Parker O Ring/Grab Ring Tube Fittings. These fittings were what was originally used in my Tartan. They are really easy to use, and they don't leak! I return to my boat after a week or two and it's still holding the pressure; I have a pressure gauge installed in the head to monitor water pressure. The only tool needed is a cheap plastic tubing cutting plier-like tool.

The tubing and fittings are available form US Plastics. The cutter I got at Loews, I think.
 
Aug 26, 2007
266
Hunter 41DS Ventura, California
jviss
The plumbing is all original plastic? and I REALLY do not want to replace any more than necessary to fix the leak. I am at the stage in my life where rather than DIY I would rather "call the guy"! Unfortunately there is no guy in my area to call without a months long wait for service.
I will use the supplier you recommended for the parts I need. Thanks
 

jviss

.
Feb 5, 2004
7,089
Tartan 3800 20 Westport, MA
jviss
The plumbing is all original plastic? and I REALLY do not want to replace any more than necessary to fix the leak. I am at the stage in my life where rather than DIY I would rather "call the guy"! Unfortunately there is no guy in my area to call without a months long wait for service.
I will use the supplier you recommended for the parts I need. Thanks
I am very happy to help you, as a consultant, on any of this. I had great success "unscrambling" my plumbing, correcting a bunch of things, and using the tubing and fittings I described.

Too bad you're not next door, I'd even help you with it!
 
Jan 11, 2014
12,273
Sabre 362 113 Fair Haven, NY
jviss
The plumbing is all original plastic? and I REALLY do not want to replace any more than necessary to fix the leak. I am at the stage in my life where rather than DIY I would rather "call the guy"! Unfortunately there is no guy in my area to call without a months long wait for service.
I will use the supplier you recommended for the parts I need. Thanks
If you have vinyl hose once the leaks start, they do not stop until it is all replaced. Over time the vinyl shrinks a little and hardens. The hose clamps no longer seal the connection and leaks form. The clamps can be tightened and the leak for stop for a while only to reappear. As soon as on connection is fixed, another will pop up. It will be an endless cycle. I cured it by replacing almost all of the vinyl plumbing with PEX.
 

jviss

.
Feb 5, 2004
7,089
Tartan 3800 20 Westport, MA
If you have vinyl hose once the leaks start, they do not stop until it is all replaced. Over time the vinyl shrinks a little and hardens. The hose clamps no longer seal the connection and leaks form. The clamps can be tightened and the leak for stop for a while only to reappear. As soon as on connection is fixed, another will pop up. It will be an endless cycle. I cured it by replacing almost all of the vinyl plumbing with PEX.
Yes, agreed, but LLDPE is not vinyl. It is widely used in the food and liquids industries and is not subject to all of the failings of vinyl. It's much less expensive than PEX, doesn't required the special connectors PEX requires, and so forth. Take a look at it, and also at the Parker O Ring/Grab Ring Tube Fittings. Super easy to use, hand tightened, and removable and replaceable, which aids winterizing. The tubing cutter is like a pair of pliers with a razor blade.
 
Jan 11, 2014
12,273
Sabre 362 113 Fair Haven, NY
Yes, agreed, but LLDPE is not vinyl. It is widely used in the food and liquids industries and is not subject to all of the failings of vinyl. It's much less expensive than PEX, doesn't required the special connectors PEX requires, and so forth. Take a look at it, and also at the Parker O Ring/Grab Ring Tube Fittings. Super easy to use, hand tightened, and removable and replaceable, which aids winterizing. The tubing cutter is like a pair of pliers with a razor blade.
That may be the case, but when a leak develops or some repair is necessary will the parts be easily available? At least with PEX, any big box hardware store will have the components as will any plumbing supply store. Shop online and buy the connectors for less than a buck a piece. Your boat, your choice. The next owner will show up on SBO wondering what in tarnation the prior owner did to his water system. I promise, in this case we'll speak kindly of the departed. ;):beer:
 
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jviss

.
Feb 5, 2004
7,089
Tartan 3800 20 Westport, MA
That may be the case, but when a leak develops or some repair is necessary will the parts be easily available? At least with PEX, any big box hardware store will have the components as will any plumbing supply store. Shop online and buy the connectors for less than a buck a piece. Your boat, your choice. The next owner will show up on SBO wondering what in tarnation the prior owner did to his water system. I promise, in this case we'll speak kindly of the departed. ;):beer:
That's ridiculous. There are probably as many Parker fittings in service, in industry, as there are PEX-compatible fittings in buildings.

Tubing and Parker fittings are what Tartan used in production.

Parker fittings are in the $1 ~ $3 neighborhood. For PEX, you need a new copper crimp piece, and you need crimp tools to assemble them.

I've never seen PEX fittings for a buck; more like $3, $5, $7, depending.

No one will find boat plumbing with LLDPE tubing and Parker fittings to be unusual.

In addition, I can undo and re-do the fittings when winterizing, or for any other reason, with my hands alone, no tools, and I don't need any new components to make them up again. It's a snap. I can reach in with one hand, even if I can't see the fitting, and simply unscrew the collar. That's it. With PEX, you'll need at least a pair of pliers and a screwdriver, probably both hands, and if you can't see it, god luck! Then to re-make it, you'll need new parts.

'Though it's not a big deal, the LLDPE tubing is about 55% the cost of PEX.

As you can tell, from my experience I'm a big fan.

If you like PEX, more power to you! I prefer LLDPE and Parker fittings.
 

senang

.
Oct 21, 2009
316
hunter 38 Monaco
On our H38, as well as another H38 in the same harbour we had a leak that originated in the aft port section of the boat. The leak had the same origin and only leaked when using the shower. It was an insufficiently tightened nut in the panel with the shower handle behind the head. Take of the shower handle, the small panel on the front and unscrew the large ring under the shower handle for access. In both cases it was a 2005 boat from the Hunter factory in Florida.
 
Aug 26, 2007
266
Hunter 41DS Ventura, California
Finally got to the boat and found at least one leak. There is a swivel fitting on the outflow side of the pump itself which uses an o-ring seal. Access to the pump is extremely difficult as it is in the small cupboard under the galley sink . I was able to get the pump out and remove/ clean/ inspect and replace the fitting and reattach but it still leaked. I didn't have a new o-ring, the old one looked ok, but obviously isn't. My next step when I get back is to install a new o-ring. If that is not successful I think I will have to epoxy the swivel in the port which will ruin the pump if it doesn't work. The next step will be to replace the pump- they don't make it any more(original 2007) and I have been unable to find one.
The biggest problem with that is that the in/ out PEX lines are up through the flooring and have little to no flexibility/ short so will be difficult to replumb. unless the replacement has the same dimensions. SBO store has either a 4 or 5 GPM pump that will work if I have to go that route.
Once I get the pump fixed I can continue the search to find any more leaks!

I don't suppose any one has a source for a replacement: Jabsco Sensor Max 14, #317950- 0000?
Thanks again to those who chimed in to help. Cheers!