I have a 2003 MKII 400 that is new to me. The forward holding tank and plumbing have a foul smell. The aft holding tank and plumbing smell fine. I could replace the plumbing and holding tank for the forward head, but of course I would prefer not to. Has anyone delt with this issue? I have pumped out the tank and put plenty of holding tank cleaner down the toilet, but it still smells. My next step may be to replace the line from the toilet to the holding tank.

Encore

Encore,
Everything I have read says that the hoses themselves seldom leak, and the tanks seldom leak. What does leak, though, are the fittings. You might try cleaning the area under the forward head sink really well, using lots of soapy hot water, and a thorough fresh water rinse. Everything should flow back into the bilge. Also do the same thing to the area around the forward holding tank, especially the outboard end, where the fittings are. After everything is clean and dry, place paper towels under all fittings. Check the next day to see if any of them are wet. If they are, you have found the problem. If not, at least you've cleaned the area, and hopefully it smells a lot better. Hope this helps.

Tom Soko
Juniper #307
Noank, CT

Much to my displeasure, I have done a lot of work to both my heads recently. I would like to echo what Tom has stated. I have double hose clamps on all my hose connections. A slight drip is all it takes for a terrible odor to develop. Also, a good way to determine if your hoses are causing the odor is to take a damp cloth and wipe it over your hoses. Then smell the cloth. If the odor has transfered to the cloth, it's time to change the hoses. If the cloth smells clean, your hoses are mostly likely ok.