Smelly bathroom sink after turning on water

[Md.FireFighter 3791RD]

Noticed this weekend that a septic smell after turning water on in the bathroom 2016 3791RD. I have had a few time water dripping in the large compartment under the bathroom storage in the front and remember a topic about that i think its called the black tank back flow proventer under neath the bathroom sink. It hasen't leaked water from that when flushing the black tank in the couple months. Is there any ideas of why,what and were the smell is coming from and how to fix this smelling bathroom sink issue. Thanks for any help or ideas Chuck.

[Montana Man]

One thing to check is the water itself. Especially if it is from the fresh water tank. If so, bleach sanitizing the lines is in order.

[Md.FireFighter 3791RD]

Water not coming from fresh water tank. Were at a seasonal spot at a campground with full hook ups. Just noticed the smell this weekend and . after water is running and i sniff the water running in my hands dont smell anything. Seems like the smell is as soon as you turn the water on.

[MidMOTraveler]

We had a seasonal setup in the past and the “P” traps would evaporate between visits.
First bit of water in sink and we’d get an odor.
Water heater when anode rod is getting bad will have a smell.

[Md.FireFighter 3791RD]

MidMOTraveler, We go every week to camper just about, and this is the first time noticing the smell. Also we only notice the smell in bathroom sink when turning water on but haven't noticed it in kitchen sink or turning shower on. I thought about anode rod but if that was the cause wouldn't the smell also come when turning other faucets on. Cant believe i'm the only one on this form that's had this issue. I'm going to drain water heater this week by the anode rod and see if the water that comes out smells just to eliminate the anode rod. Thanks.

[K0LCB]

Check the AAV under the sink. If it’s bad, you could be siphoning water from the trap

[Md.FireFighter 3791RD]

KOLCB,is the AAV your talking about that the black piece that people talk about leaking all the time when using the black tank flush that there replacing and some are eliminating all together and if so how do i test the AAV. Thanks.

[Kyle and Lisa]

We have noticed a septic smell in the past, but only when running the ceiling exhaust fans with the trailer closed up. 2018 3790RD

[Md.FireFighter 3791RD]

Kyle and Lisa, exhaust fan not on unless were taking a shower. I have heard of that problem on here before but, only the AC is on and still notice the smell just this weekend so far. Im just confused to why it's happening now.

[Kyle and Lisa]

Recently there have been a lot of complaints of battery gas smell, you might check the water level, it had been a while but recently checked ours.

[Md.FireFighter 3791RD]

Yes i even thought of that also about the batteries,remembering reading on here about that. Haven't physically checked the battery by removing the battery box lid but were the box vent comes through the front wall were the vent comes through i took a sniff in the vent but didn't smell anything .

[Lenny K]

Originally Posted by K0LCB

Check the AAV under the sink. If it’s bad, you could be siphoning water from the trap

KOLCB was talking about the air admittance valve you might have. Easy to replace.
https://www.amazon.com/Oatey-39012-A.../dp/B000KKSP52

[Md.FireFighter 3791RD]

Oh ok Lenny K. Really didn't notice if there's one of them under bathroom sink but i no there's is that other valve for black tank flushing that's been a issue. I know there's one of those AAV under kitchen sink ,the center island. Thanks for letting me know what the AAV stands for.

[Lenny K]

You can pickup those valves at Home Depot and Lowes also. If you have one under the sink you can almost be guaranteed that's where your smell is coming from.

[Md.FireFighter 3791RD]

Lenny K, would we only smell it only when turning water on or all the time in bathroom. I have only noticed it really just when turning the water to wash our hands.

[Carl n Susan]

Are you plumbed for a washer dryer? Do you have a washer dryer installed? If no washer/dryer then the problem is most likely stagnate water in the water lines feeding the washer.

Flush out the lines and the smell will disappear.

[rohrmann]

We have had the smell issue from the bathroom sink, only occasionally. It seems to only happen after the rig sits for a while with minimal use, and found using a packet of Odorlos down the sink solves the problem. We normally do not use a gray tank treatment as we usually drain it at least every other day. I'm sure most any other tank treatment will work as well.

[Md.FireFighter 3791RD]

Carl how you suggest i drain or flush out washer lines since there's no washer hooked up.

[jeffba]

short hose from washer faucet to Washer drain would be my guess.

[Carl n Susan]

Originally Posted by jeffba

short hose from washer faucet to Washer drain would be my guess.

Exactly!!! Be sure to do both the Hot and the Cold.