We are always pretty frugal with our grey water and use Tubtrugs for dish washing so most of our nice soapy water is then dumped down the toilet to the blank tank. We decided to practice extreme water management recently while boondocking just as practice for our two weeks in Acadia with no hook ups. All went well until we kicked the propane water heater on for a few hours (we only turn the hot water on when needed).

We started getting a really funky smell that we tracked down to under the sink where the hot water heater lives. We were afraid something melted, burned, died, decayed... something! After dismantling the lower cabinet around the hot water heater (and finding a nice wrench that Phoenix lost in there) and much sniffing of random objects (definite ewwww), we guessed it was the vent for the drain pipe. We figure whatever sludge was in the pipes got heated up and fermented or did something and the odor was wafting out the little metal screen under the sink.

We promptly dumped a bunch of baking soda down the drain and hit it with vinegar to bubble out as much as we could. It still smelled, though not as strong. We then filled the sink half way with warm water and put in about 10 times more Dawn dish soap than I usually use and pulled the plug to give a good whoosh down the drain. When we got up this morning the smell was gone! We will try to remember to do a good drain/trap cleaning before we boondock to avoid the stink in the future.

So if anyone gets a weird smell under the sink (but not from the top drain), try the super cleaning tricks before you dismantle your cabinets. It's so much easier.

Great tip....it's going in my 'If this happens, check this' section of my notebook!

Please post your results after your Acadia trip!  I'm interested in what that would be like on a daily basis for a week or two (showering, dish washing, dumping the tanks at some point, etc)

    - Mike

A rotten egg smell would be an propane leak. You might want to check for leaks around the water heater or better yet have the whole system water tested for leaks. You would need a tool for water testing which most RV places and gas companies have. The test takes about half an hour.

To clean plumbing pipes use "Instant Flow" which can be found in hardware stores.

Thanks Tom, but it was not propane. I'm real sensitive to smells and knew it wasn't propane but we couldn't figure out what it was. I've never heard of instant-flow. Is it safe for RV pipes (pex)? The drain wasn't plugged, I think we just had gooey stuff in there that we percolated. I figure some black lagoon type creature would have crawled on up if we hadn't flushed it out. True kitchen science. We're going to try to avoid creating new life forms from here on out.

It claims to be safe for all plumbing and septic systems. I have started using it to clean 35 year old pipes at home and it works.

 We purchased our PC in Florida, drove down in our class A to trade.  We didn't carry much in the way of supplies such as dish towels and dish detergent since we only planned on one overnight on the way home.  Anyway, we microwaved a frozen lasagna which made a real mess.  I left the dirty dish in the sink with water to soak till we got home the next day where I could wash and scrub.  As you all know, we have deep sinks with nice solid surface covers in our PCs.  A couple of days later, as we were setting up and adding things to our new toy, I kept noticing a terrible rotten smell.  Thought  it was from a poorly cleaned holding tank.  Sniffed all over the motorhome.  Finally lifted the cover on the sink and you guessed it.  I had forgotten all about the nasty dish in the sink.  Lesson learned.

I know your problem wasn't like that, but had to share my big oops.  Sometimes  you can have a good laugh.

That's a good one. 

Our "Stink" story had a different twist.

Arriving home one trip, we emptied everything out from the rig in a hurry.  About a week later I went inside to put stuff away and something didn't smell right inside.  Along with that was a gang of fruit flies.  We forgot to take out the trash.  Our trash can has a foot activated lid and we missed it.

Another time, we left the coffee filter with grounds in the coffee maker for a half year.  That didn't stink but it sure looked scary with strange fuzzy growth in the coffee basket.  Needless to say we had some serious cleaning then too.

Fortunately no permanent damage from either mishap.  Eventually the new car smell, PC leather took over once again.

I'm better at keeping the poop tank fresh than the inside of our PC.....sheesh!