rwitt Report post Posted January 2, 2016 I know there is a lot of information around about this issue, but I need to see if anyone has any idea after you read what I have already done. I have a 2008 Monaco Camelot and have been in this RV Park for 3 months. The grey tank has always been open since we have full hookups. Yesterday we came home to the recognizable pungent odor of sewer in the unit. After a brief investigation and "noising around" I found that it was coming from under the sink in the rear bathroom. First thing I did was to close the grey tank and after running the vents for a while the odor was gone. Next, I went to Lowe's and got a new vent and replaced the one that was there. Opened the grey tank and within 15 mins the odor was coming in. I closed the tank again and then swapped the vent with the one in the front bathroom sink that was not having a problem. I thought maybe this might show that the one I just purchased was bad and the odor would come from the front bathroom. NOT the case..... opened the tank and the odor still came from the rear sink. I've cleaned out the sink and shower drains with Dawn detergent and sprayed a lot of hot water down the drains. Opened the tank and the odor is still coming in. It is only coming from the rear sink. The other bathroom sink and the kitchen sinks are fine........................... What's next???????? It's a real pain having to open and close the grey tank so I'm hoping to get this resolved soon. TIA Ron Share this post Link to post Share on other sites
wolfe10 Report post Posted January 3, 2016 Ron, I assume what you replaced was an air admittance valve??? Share this post Link to post Share on other sites
rwitt Report post Posted January 3, 2016 Yes, Brett that is correct. Share this post Link to post Share on other sites
wolfe10 Report post Posted January 3, 2016 Temporarily use a baggie or saran wrap and a rubber band to seal it off. That will tell you very quickly if that is the source of the odor. Share this post Link to post Share on other sites
kaypsmith Report post Posted January 3, 2016 What about the vent on the roof? If that vent pipe gets stopped up, there will be no way for the odor to escape except into the coach.A bird may have built a nest in it, or some other critter. Share this post Link to post Share on other sites
rwitt Report post Posted January 3, 2016 Brett, I did that to confirm for sure the source of the odor and that is it. If the vent on the roof was blocked wouldn't the odor be coming through any/all of the air admittance vents? Share this post Link to post Share on other sites
Lenp Report post Posted January 3, 2016 If the vent is plugged, odor would most likely come from the admittance valve closest to the tank. Lenp Share this post Link to post Share on other sites
rwitt Report post Posted January 3, 2016 OK, Thanks. I'll check the vent on the roof as soon as it quits raining. Hopefully, sometime tomorrow. Share this post Link to post Share on other sites
jlandon13399 Report post Posted January 3, 2016 Since you have left you grey tank open you are probably not flushing the tank. Solids from there kitchen have built up and are rotting. Best to close the grey tank, put in 1 cup of dishwasher detergent, fill it, and then flush to tank after flushing the black tank. If you are not on the road it may take several flushings to break loose the grey tank build-up. Share this post Link to post Share on other sites
kaypsmith Report post Posted January 3, 2016 I personally never leave the gray or black tank open for these very reasons, I open the gray valve every other day, and the black valve before opening the gray valve on fourth day. Also the sewer system has an odor that we do not like, so keeping the tank valves closed helps eliminate that odor, especially when flushing the toilet. Share this post Link to post Share on other sites
tbutler Report post Posted January 3, 2016 Do you have a washer/drier in your coach? Is it located in or near the rear bathroom. If so, are you using it on a regular basis? If you yes to the first two questions and no to the last, it could be your problem. We have to add water to the W/D drain to keep the trap filled if we aren't using it on a regular basis. It is very difficult to identify exactly where an odor comes from in my experience. If the trap for the W/D dries out, it will allow gases from the grey tank into the coach. The air admittance valve or vacuum breaker should be a one way valve that allows air only when there is negative pressure of the drain. It's purpose is to keep water draining from the sink from siphoning the P (or S) trap leaving no water in the trap to prevent gases entering through the drain trap. It should never allow air to flow in the opposite direction if it is functioning properly. If there is water in the trap for the sink and shower then they wouldn't allow gases from the grey water to enter the coach. Share this post Link to post Share on other sites
britcon Report post Posted January 4, 2016 Sewage odor from the grey tank can smell worse than the black sometimes. We use 1/2 cup of Oxyclean mixed with 2 cups of hotwater, into a partially filled closed tank. Seems to do the trick. Occasionally we will do this after dumping, prior to moving down the road so stuff has time to swish around a bit. Share this post Link to post Share on other sites
wajames Report post Posted January 4, 2016 I've had the w/d dry trap issue, the not-glued-together roof vent line that passes through a commode closet, the broken toilet inlet - and vent - piping into the black tank, etc. Our bathroom sink smells occasionally due to hair, etc caught in the sink drain "aging". Cleaning it and hitting it with a dose of bleach fixes that. Before we got the SewerSolution, I always put a bump in the sewer hose to create a "P-Trap" effect to keep sewer gas from coming up the hose. Share this post Link to post Share on other sites
Tcamperman Report post Posted January 4, 2016 I might ask whether there is possibly a "P" trap somewhere that may have dried to the point there is no water in it....possibly a washing machine that hasn't been used recently. There might be a "gas vent" beneath one of your cabinets that could be stuck open also. ....Just a couple of things you might check for. Not telling you what to do, but a grey water tank can develop an incredibly unpleasant odor what with bits of food scraps, etc getting washed down the sink....not to mention a full tank simply empties better and carries that debris with it. On our MH, we hold both tanks. When I dump, the black is first with the grey next for the first rinse of the hose, etc. If you leave your grey valve open there's a straight shot from you nose to the gopher hole, if you do happen to have a gas/smell leak somewhere. Share this post Link to post Share on other sites
wolfe10 Report post Posted January 4, 2016 The other "almost like a black/gray tank odor" is from an over charging battery (bad cell or too high a charge voltage). So, do the "sniff test" around your batteries as well. Share this post Link to post Share on other sites
mewhichard Report post Posted January 4, 2016 I fought a black tank odor for years only to discover that the vent pipe had come loose from the grommet it sits in. Go online and get the plumbing schematics for your coach-- locate the vent pipe. Access should be through one of the interior vent panels on the wall somewhere. Make sure that is tight and in place. Almost sold my coach because nobody, including Winnebago suggested checking the vent pipe where is connects to the tank. Mark Whichard 2008 Winnebago Voyage Share this post Link to post Share on other sites
mstobias101 Report post Posted January 5, 2016 Some RV manufacturers are using a one-way check valve in place of a P trap in the drain lines. The valve is called a HepVO and is usually located where the P trap would be. It has a duckbill valve inside. Contrary to what you may hear, the valve can become clogged and stuck open. It can also get damaged if you ran a plumbers snake down the drain. You can remove them from the drain line, disassemble and check them out for cleaning or replacement. Be sure to reinstall pointing in the right direction! Share this post Link to post Share on other sites
huffypuff Report post Posted January 5, 2016 I believe the gasses are coming up from the campground sewer lines when you leave the gray valve open like Kaypsmith says. I never leave the valve open and have minimum odor as a result from toilet only. I'm not saying what other saying isn't right but I don't think leaving a dump valve open to open campground sewer is using as designed and not going to end in good results. When staying long term I watch the monitor level gauges to open valve only when needed. Share this post Link to post Share on other sites
jackvliet Report post Posted January 6, 2016 Have 99 35 ft Winny the glue free fitting that dumps into the gray tank from the kit. sink was lose & the smell migrated up into the cab. I was able to put a #28 SS hose clamp, so far so good. Share this post Link to post Share on other sites
Lenp Report post Posted January 6, 2016 If you want to leave your gray valve open, route the sewer hose so that is has a "P" trap in it. That will prevent the sewer gas getting into your tank(s). Lenp Share this post Link to post Share on other sites
tbutler Report post Posted January 6, 2016 When we are in a campground for any length of time we always leave the grey tank open to the campground sewer. I route it straight to the sewer, no loop to collect sediment and act as a trap. We have never had a problem. This includes years of being stationary for the entire winter at our winter park. The black tank is always closed until it is ready for emptying but otherwise, if we have utilities the grey tank is open. Share this post Link to post Share on other sites
indianpoint Report post Posted January 8, 2016 Just one more view on odor in coach. I work for a water dept and have had the same issue ODOR in coach, iron and manganese from a well with manganese. The smell of sulfur can get into you water system, booster pump and tank. This is common when travel to different camp grounds and using the water or worse taking on water from the.water system. When checking in ask if the camp ground if manganese is in the water and do they treat for it as they are governed by DEP clean water act.. you don't notice till the water get warm from traveling or sitting for a day or two. If you think a filter will work it will be expensive to buy a special filter. Bottom line is chlorine is good but breaks down and releases the manganese and the odor problem is back. The only way is to flush water tanks water lines and booster pump (as your booster pump stays idle when hooked up the a water system with pressure keeping booster off) and fill with treated clean water and add extra chlorine in the tank (keep a gallon of chlorine with you). Bottom line check for MANGANESE. I have this problem in Salem Mass. and one other place in New Hampshire. It.s all ways good to flush your system often in the summer months. Happen to know if this resolves your problem. Happy Travels Dave P 2002 Country Coach owner Share this post Link to post Share on other sites
bgc Report post Posted January 27, 2016 Do you have a washer/drier in your coach? Is it located in or near the rear bathroom. If so, are you using it on a regular basis? If you yes to the first two questions and no to the last, it could be your problem. We have to add water to the W/D drain to keep the trap filled if we aren't using it on a regular basis. It is very difficult to identify exactly where an odor comes from in my experience. If the trap for the W/D dries out, it will allow gases from the grey tank into the coach. The air admittance valve or vacuum breaker should be a one way valve that allows air only when there is negative pressure of the drain. It's purpose is to keep water draining from the sink from siphoning the P (or S) trap leaving no water in the trap to prevent gases entering through the drain trap. It should never allow air to flow in the opposite direction if it is functioning properly. If there is water in the trap for the sink and shower then they wouldn't allow gases from the grey water to enter the coach. Thanx so much for this info. We had this problem a few times during our trip from Maine to California and back (2015) and it almost drove the 2 of us nuts. I have nose for smells, husband is retire pipefitter so we tried a lot of things, and I had narrowed it down to w/d....but didn't know the why. We had a great trip but every day brought a new challenge .... from cupboard door latches, to lights, batteries, and fridge problems. A real experience across a beautiful country. We are from New Brunswick, Canada so it was a treat to see some new things. The things advertised as "must sees" were not the rule though. The off the beaten track were where we had the best adventures. Share this post Link to post Share on other sites
manholt Report post Posted January 28, 2016 bgc, welcome to the Forum. The original Poster must have found the answer also! Glad we could be of help! Carl Share this post Link to post Share on other sites
wndseek Report post Posted February 2, 2016 Ron, I have found the best way to end the odor problem in all my drains is to shut the BLACK WATER & GRAY WATER TANKS, shut all the sinks using the sink stoppers, and adding half water and half Clorox to every sink, at the same time I add the 1/2 water to 1/2 Clorox to all my toilets, the dishwasher, the clothes washer and finally I buy a flat sink/tub stopper to stop the shower from emptying too soon. I let all drains sit for about 10 minutes then release all sinks, toilets and shower at the same time I run the clothes washer and the dish washer. I let the solution stay in the BLACK & GRAY TANKS for 30 to 40 minutes and then empty then, close them again until the washers, both clothes and dish, finish. Then once a week I repeat in the routine in the toilets and sinks and no smell. This keeps bacteria way down and your coach smelling great. If you can't use Clorox, you can try Lysol or Mr. Clean with Febreze. I have found that this way I can open and keep open my tanks without problems. Hope this helps you. This method also works in a non-moving house or apartment. NANA Share this post Link to post Share on other sites
