1987 Montego 3257 cabin smell

[cap10ace]

I just read thread on bilge water in montego midship. Water is always present, however the bilge/cabin always has odor. I replaced holding tank and sani lines 5 years ago. Also removed electric overboard pump and installed hand pump type.
This year I installed New toilet and piped into fresh water with solenoid and check valve. Installed new hoses for fill, flush, vent, and sani lines to pumpout. Installed new Y-valve and locked to pumpout only position. When I piped tank I inspected interior and exterior including all plugs, no signs of leaks.
I am at wits end as to cause of smell. Is tank composition a possible cause? It is West Marine.

Thanks

 

[MikeeH]

Have you looked at the shower sump? It should be in your mid bilge, under the access right outside the head. We had a problem with ours once and the grey water overflow got into the bilge. After a few days it really stunk the whole cabin up. Salt water will do the same thing if it lays in there so even if its the usual trickle from the logs it will start stinking. If you're not sure just dump a cup or 2 of cheap liquid bleach into the mid bilge and give it an hour or so. If the stink dissapates you know its the water laying down there and then you just need to find it source and stop it from collecting.

 

[cap10ace]

I think you're onto something. I had standing water in shower sump and lose hose clamp. Never even considered the grey water. Treated last night will check this week.

Thanks