Fresh water leak

[AbeFroman]

I have a 1985 10 m international series convertible. The boat was rebuilt almost entirely two years ago . I have a fresh water leak but it only leaks with the water pump on . If I cut the pump off it does not leak anymore . I have only owned the boat for a week and I have no idea how to access the freshwater tank . All the lines that are visible through any hatch that I can access are dry. Can anyone help me figure out where to begin to look for this leak?

[The Dog House]

If it only leaks with the water pump on, the leak should be somewhere after the water pump (between the water pump and the faucet). The water tank should be fine.

[Big D]

Need to clarify a couple of things; do you suspect a fresh water leak simply because there is water in the bilge, or do you hear the fresh water pump cycling even when no water is being used?

If the fresh water pump is cycling, then there is a leak anywhere from and including the pump to any one of the faucet fixtures. You'll need to get under or behind every fixture to check for a leak. Don't forget the transom shower or fresh water washdown if you have one. Also in the loop would be an ice maker if applicable and the hot water tank. The hot water heater could be leaking at the fittings or from the tank itself. Look for water at the base of the heater. If you have a Vacuflush head/toilet that draws water from the fresh water system, check it also. The pump's internal check valve may also be leaking back which would cause the system to lose pressure and cause it to cycle. Any one of the fittings is suspect too like an elbow or tee. What kind of lines/hose and fittings are on board?

If you don't hear the pump cycling when you're not calling for water but you see what you know is definitely fresh water and not lake water, then the leak could be from the tank or an external source like rain. If you're unsure it's fresh water, then it could also be lake water.

[Flyboy]

I agree with Big D, what are the symtoms, as he said, is the pump cycling or do you see water accumulating somewhere.

[AbeFroman]

The pump is not cycling when I'm not calling for freshwater but I am noticing water coming out underneath the drawers in the galley on the port side right about where the freshwater tank fill is. It is not a severe leak to the point where the freshwater tanks would drain very fast or anything but there is definitely water coming from somewhere and my boat is in salt water and it's not salt water so it may be rain but it hasn't rained here much lately . Also when I cut the water pump off the leak stops so I think I need to access the freshwater tank to check the lines coming off of the tank and the pump but I don't know how to get to it without tearing stuff apart and I can't figure out where my access point is.

[Flyboy]

Well, if the pump does not cycle then I do not understand why the leak would stop whith the pump off. If your boat is anything like the 10 meter international, your water tank is built into the hull. If you have an acess panel in the middle of the cabin, the bottom of that area is the top of your fresh water tank. My water pump is in that area, however some have the pump in the bilge area at the bottom of the steps. The supply hose from the fresh water tank is in that bilge also. Your galley sink also drains out the port side of the boat, that could be leaking from using the sink. Good luck.

[AbeFroman]

Thank you for the help I will investigate all your suggestions and I wil post what I find.

[Drafter]

In an effort to find my own fresh water leak, I eventually poured red food coloring into my freshwater holding tank and let it sit with no pumps on, just to determine if my tank leaked. I always had fresh water in my front bilge, and it was driving me crazy,! 3 weeks, and not a drop of red water. I knew it stayed dry when winterized, so also knew it was coming from within. Able to write that off, my next step was to turn on the water pump, and search for red water. If that wasn't it, I would focus on clear a/c condensate.
My boat resides in a covered dock, so rainwater was already ruled out. It took rinsing off the back deck with a bucket of lake water thrown over it after the dock water had been turned off for the season to finally figure it out. I wash my boat just about every weekend, therefore always had water in the forward bilge. Even sucked out, residual water would be back the next day. I always wondered if the rear bilge near the lazerette was connected to the front. My aft bilge pump sits in dust, so I ruled cockpit water out long ago. Turns out, water leaks between the cockpit seams, under the engine room liners, (bilge) and to the forward bilge. It all moves forward vs ever hitting the aft bilge pump. I almost thru a party after finally figuring this out! Can't wait to crawl in the lazerette this spring, turn the Mrs. loose with the hose above, and finally see what's been happening all of this time! I have the same year and model boat. Also for grins, I bought a $12 endoscope camera for my phone online and took a look see what a 30 year old holding tank looks like from the inside. I dropped it into the fill connection on top of the tank at the galley stair hatch. Surprisingly....really not that bad!

Good luck!