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Freshwater Leak on 45DS

May 4, 2012
Hunter 45DS Toronto
I am hoping that someone else has run into this before, I am at my wits end.
Ever since the boat was new, there has been a freshwater leak and I have not been able to find it.
It seems that the leak gets bigger each spring but in the summer it slows down and stops!!!
Has anyone ever run into this?
Any advice?
Sep 22, 2009
Hunter 36 Seattle, WA
What are the symptoms of your leak? And how do they change from spring to summer? And (given your location) how do you winterize and commission your boat?
May 4, 2012
Hunter 45DS Toronto
I see the water in the bilge and cant find where it comes from. It only appears after I fill the fresh water tanks. Over the season the leak seems to slow to a stop?? In the winter all the plumbing I'd filled with marine plumbing antifreeze. Commissioning, I just fill the tanks and flush the system.
Feb 26, 2004
Catalina 34 224 Maple Bay, BC, Canada
It only appears after I fill the fresh water tanks. Over the season the leak seems to slow to a stop??
Would seem to indicate something related to only full tanks. Access hatch leak or where the lines come into the tank (loose hose clamp or fitting).
Feb 16, 2012
Hunter 45 CC Alamitos Bay, Long Beach
I am not sure what your boat is, however I had a somewhat similar problem with my 2005 45 CC. In my case the leak would only appear when I had the fresh water pump "ON". If this the case with your leaks try this: First of all try finding the leak by isolating one fresh water system at a time. This can be done by turning off one of the valves located on the fresh water manifold, which in my boat is located under the galley sink. Be sure that your fresh water pump is "ON". You will notice that there are both HOT and COLD valves. The showers / sinks have both hot and cold, and the heads have just cold. Not sure if you have fresh water heads. I found both of my leaks this way. One was the hot water connection to the mixer valve in the forward shower, and the other was at the hot water heater located in aft cabin under the bead. Be sure to only turn one valve off at a time. Hope this helps.
Feb 14, 2014
Hunter 430 Waveland, MS
Your tank(s) is located under floor per...

Mine is in same spot and it is a polymer tank. I had a major leak not found by the Previous Owner.
Here is what happens to polymer tanks after many fill/re-fill cycles.

The top is poly welded and when the tank is overfilled the tank will actually...

Mine had the welded edge crack.
I simply ground out the leak area leave the slight notch and the I repaired with the tried and true 3M 5200.

When I was verifying my repair the tank ballooned again and I couldn't replace the deck board until I reduced the tank level.:yikes:
Also remember the tank has a vent line to let air flow in and out on water level changes. A loose vent line will leak on overfilling.

PS: Removing and replace the deck floor was a royal pain, since mine was cut in a stylish curve.:rolleyes:
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Jul 31, 2016
Hunter 380 Cape Coral, Fl
On My H380, I have a fresh water leak also, which is better than a salt water leak. Turned off water pressure and leak went away. Isolated to the cockpit shower. H380 did not have cutoff valves for the water lines under the sink, although they appear to all run to that point. If not so tight in that location ,would be a great idea.... I could cut of just the shower line until the new shower comes.




Oct 21, 2009
hunter 38 Monaco
On my Hunter 38 the freshwater leak was in the bathroom shower manifold. Leaked only when the shower was on. Found it by accident when installing an extra sump pump switch. There was a nut not tightened on the hoses to the manifold.


Jan 20, 2005
Nauticat 321 pilothouse 32 Erie PA
1/ turn off freshwater pump. be sure h 2 0 tanks are full. 2/ wrap some (dry) kleenexes around each pipe joint and hose connection . 3/ turn on water pump for a couple minute s. open the fixture closest to the tank. 4/ working from freshwater tank, alook at every joint where you've placed the kleenex and see which ones are wet. particularly look for areas where the plumbing supply line enters the faucet or water heater, etc.
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May 4, 2012
Hunter 45DS Toronto
I found it. It took a little while and it was surprising. I isolated the leak to cold water that serviced the forward head, shower and sink. All connections were dry. I removed the medicine cabnet in the forward head and found that there is a Solenoid Valve & Siphon Breaker servicing water to the head and it was leaking badly but there was more.

I also discovered that the hose from the shower sump was never connected to the through hull. It looks like it was missed when they built the boat.

The parts are now on order and I look forward to a dry bilge.
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Dec 20, 2009
Hunter 466 Bremerton
My 2003 H466 had an annoying fw leak as well. Could never get a dry bilge. Traced it to an improperly installed fill line in my aft stbd tank. The factory had to know about it as it was so obvious once the floorboards were removed. Where was QA? Not too bad to fix it but totally unnecessary.