fresh water system leak!

[Krill]

this is really starting to irritate me as i cant find a solution as to where its coming from.

Boat - Bav 30 Cruiser 2006

Info - Its definitely fresh water and also from the tank / pipework leaking when the tap is left pressurized, if i use the taps but switch the pump off immediately while keeping the taps open afterwards the bilges are nice and dusty!

also the pump never comes on either if the water is left on over night, its like it only ever leaks above a certain pressure, but it never loses enough water for the pump to re-engage

where the water appears - Middle bilge in the saloon next to the galley sink (always a small amount, a small cup full each time) but its the lowest point of the boat where the bilge pumps are so unrelated.

to try and solve it;

- Looking at all the tap fittings and also using tissue paper while the system is pressurized to check for wetness - and nothing.
- Leaving the system pressurized overnight and strategically putting tissue paper around the boat (i.e. in the heads, below shower tray, in the cupboard with the sea cocks under the tap / shower, the deck shower head at rear of the boat, and all bone dry.

the engine bilge is always dry as are the rest, its not rain water as if i leave the system un pressurized in heavy rain all the bilges are dry.

i must have a pin hole leak under pressure in the pipe somewhere but where? i've checked all the obvious connections, my next port of call is to just buy new plastic piping and rip it all out and start again, but before i go down this route i'm missing something obvious right?

maybe i can turn the pressure down on the pump and see if it leaks then?

[Salty]

For the water to just appear where you have marked on your plan, it must have travelled through the interconnecting waterways made by the box section floors between the cabin deck and the hull. Look at each one for the drain hole through which the water would have to flow, and keep in mind that for water to flow out of that hole it first has to build up to the point where it can overflow the lower edge of the drain hole. That would mean that any water remaining within those box sections must be at a level not quite enough for any immediate overflow, but probably enough to remain visible within the area just inside the drain hole. Next look at any other drain holes for traces of water, and this may give you an indicator in which direction to continue focussing your attention.

Good luck.

[Odysseus]

Looks like you have tried most things, however you could look to see if the water is the fridge drain that on my 38 comes into the bilge by table seat.
Put a cup of water in bottom of fridge.

All the best.
Odysseus
Bav 38

[Clivert]

Check the outlet from your hot water tank.
We had this problem on our 34 and founf that we had a dribble from the hose where it was attached to the tank.
Check your tank outlet for drips and if leaking, cut the end off the pipe and re-fit.

[SYJetzt]

maybe your boiler has a pressure relief valve, which is not tight. If boiler heats up the water, it will expand thru relief valve

[smaugi]

Do you have checked if the problem is only with completely full water tank ?
I have a Bav33/2006 and I had a similar problem. But in my case the water comes out of the seal of the inspection cover when the tank was totally filled.
It takes me years to find the reason.

[Krill]

To get the water into the center bilge i have to sail some where, by which time everything has sloshed around everywhere leaving the tracing difficult. - all i know is its either the heads or galley as the stern & engine bilges are bone dry

but it's got to be coming from the pipework as it only leaks when pressurized

regarding the hot water, i unplugged the heater for a while to see if this solved it and still it leaked, the water heater lives under the aft bunk and its dry in that area too, pressure relief is dry too.

As long as i run the water out the taps its fine, just annoying to turn the switch off every time you use water, but that way there is 0 water in the boat, I'd just like to leave my pump to work automatically

i'll check all the points mentioned again as i've been in all these areas a few times now without success, failing that i think i am resided to the fact that i should replace each pipe until it goes away.

[smaugi]

I drilled two holes in my boat so that water flows directly to the center bilges.
So I can recognize the water much faster if it flows around

[Jeff Jones]

sprinkle some talc powder lightly down around the edges of the bilges and work backwards towards the leak. the leak will wash away the powder and show the track.

[Krill]

well i have found this mischievous little PITA leak finally!

There was a T fitting with a split pipe right next to the hole where the auto bilge pump hose went through in the aft cabin near the water calorifier.

so it basically dripped onto this hose and straight into the cross members but not only this the bilge hose was acting as a funnel of some description as the water would cling to its outside and travel all the way down into the central bilge, where i was finding the water.

Because the leak was right next to the hole the aft bilge was nice and dry of course and was never under suspect of leaking! on the plus side i do now know the boat inside and out and every nook and cranny behind the engine where the saildrive lives, im pretty sure i also invented some new yoga positions to fit the replacement T section hidden in the depths of a spiders nest of piping i cant but help think there is a better way to plumb it. but thats for another day, its now fixed and there is sailing to be done

[nightowle]

Ha!  Isn't it just the laws of boat maintenance that it will turn out to be a least suspected and difficult to access place.  Thanks for the update - I think we've all suffered something similar tracking down leaks on our Bavs.  But, I still love the boat!

[IslandAlchemy]

It's not the deck shower is it?

[saltash182]

I have a 2006 B30 and had the same issue, however mine leak was coming from a small pin hole in the hot water tank and tracking down in the the same area you have water, i had the tank welded last week and i have reinstalled so hopefully that has sorted out the issue

[Baddox]

I’m pleased to see that the OP has found the source of his leak.
When we had a leak on my wife’s boat, it came from a failed rubber o-ring in one of the hose connectors.  The leak only occurred when the water tank was filled to the brim.