Gray water tank smell?

[hlh1]

I've been chasing a smell in the RV that we only notice when it's closed up and not in use. We only notice it around the kitchen sink and not around the bathroom toilet and sink. The kitchen sink has a standard trip, but we still get the smell. Today I looked under the kitchen sink, and against the outside wall, and see this vent. The pic is a bit dark and on its side, but the vent is visible and it's on the tank side of the trap. I bet this is where our smell is coming from, and why isn't it on the roof?


This RV has two gray tanks and the kitchen sink has its own dedicated gray tank.

[wiredgeorge]

Many homes and RVs use this type vent when a roof penetration is feasible. Buy a better quality vent if your vent allows stink from the pee trap. There are two companies that make better quality vents. Studor and Oatey come to mind... probably others and you will note these type vents cost about four times what the cheapest ones cost (and for a reason). Your vent was likely one of the cheap ones. To purchase, take in the old vent (it unscrews) and match diameter of the fitting and thread. Vents come in several types of fitting diameters and maybe thread (male/female, etc.).

[hlh1]

Originally Posted by wiredgeorge

Many homes and RVs use this type vent when a roof penetration is feasible. Buy a better quality vent if your vent allows stink from the pee trap. There are two companies that make better quality vents. Studor and Oatey come to mind... probably others and you will note these type vents cost about four times what the cheapest ones cost (and for a reason). Your vent was likely one of the cheap ones. To purchase, take in the old vent (it unscrews) and match diameter of the fitting and thread. Vents come in several types of fitting diameters and maybe thread (male/female, etc.).

Ok, so just take it to the local plumbing store and find something better?

[JRTJH]

An easy way to determine if that "failed vent" is the source of your odor is to simply put a plastic bag over the end of the vent and tape the bag around the pipe supporting the vent. Doing that will cause a "slow drain" if you use the sink, but will seal the vent from the interior space. If the odor goes away, buy a new vent to install. If the odor remains, it's not the vent, but another source that's allowing the gray tank odor to penetrate under the sink cabinet.

The plastic bag is not a solution for the odor, just a means to verify the vent is leaking "foul smelling air" into the cabinet.

And yes, Lowe's or Home Depot or any local hardware store will have replacement vents, but take the old one with you because there are different size "attaching threads" on different brand vents.

[wiredgeorge]

The vent is the source of your stink. You could also remove the pee trap in addition to replacing the vent with a better quality vent and then clean the pee trap out. Stuff starts to grow in the stagnant water in the pee trap if not used frequently and cleaning with a bit of bleach may help.

[hlh1]

Good idea John, I'll give it test first.

[NH_Bulldog]

The check-vents are often the issue. I replaced mine with Studor vents. They are about $20 more than the ones in there now, but well worth it. As a side note, I found the grey tank to often smell as bad as the black tank, so I started dropping a tank pod down the kitchen sink drain after each tank emptying and it helped a lot.

[hlh1]

Originally Posted by NH_Bulldog

The check-vents are often the issue. I replaced mine with Studor vents. They are about $20 more than the ones in there now, but well worth it. As a side note, I found the grey tank to often smell as bad as the black tank, so I started dropping a tank pod down the kitchen sink drain after each tank emptying and it helped a lot.

I've not been adding a black tank enzyme to the Gray tank, but I should probably start doing it as you suggest. The kitchen gray tank will have some food residue that will rot and stink.

[CedarCreekWoody]

This is an AAV, or air admittance valve. It aids sink draining and prevents the P-trap from having the water sucked out.

[dutchmensport]

Well, I have a different theory why the smell? It has nothing to do with your air admittance valve. Rather ... check your p-trap and make sure it still has water in it. If the water has evaporated, then smells can...and do, come up from the tanks.

Pull the trap. It's very simple, just unscrew both ends and pull it off. If it's got no water, or very little, allowing air to pass through it, then...that is your culprit.

Check that first before anything else.

If your camper is closed up, chances are it gets really warm inside, maybe even hot. This makes the water evaporate even faster. Anyway, check this out first before doing anything else.

[hlh1]

Originally Posted by dutchmensport

Well, I have a different theory why the smell? It has nothing to do with your air admittance valve. Rather ... check your p-trap and make sure it still has water in it. If the water has evaporated, then smells can...and do, come up from the tanks.

Pull the trap. It's very simple, just unscrew both ends and pull it off. If it's got no water, or very little, allowing air to pass through it, then...that is your culprit.

Check that first before anything else.

If your camper is closed up, chances are it gets really warm inside, maybe even hot. This makes the water evaporate even faster. Anyway, check this out first before doing anything else.

Good thought, but I winterized the TT last week and poured antifreeze into the sink to fill the trap, so it should be full.

[dutchmensport]

Originally Posted by hlh1

...poured antifreeze into the sink to fill the trap, so it should be full.

I winterized last week also, and the residual around my shower drain is completely dried up now. It doesn't take long for RV antifreeze to evaporate either.

I pull my P-traps under my kitchen and bathroom sink and dump any remaining water or RV antifreeze in them. I then put a plastic sandwich baggie over the (now) open pipe and tie it off with a rubber band or a string, or a wire to use as a twistie tie. This keeps oders from coming up. When I un-winterize, I replace the P-traps and of course, run water to flush the antifreeze from the water lines. This seals the p-traps again with water.

You might check anyway. If nothing else makes sense, then sometimes you have to go with with the things that don't make sense. Put a plastic bag over the open drain until spring. See if the odar dissipates.

[slow]

Pour enough mineral oil into the drains after winterizing to create an oil film on top of the antifreeze. It prevents evaporation.

[German Shepherd Guy]

Originally Posted by slow

Pour enough mineral oil into the drains after winterizing to create an oil film on top of the antifreeze. It prevents evaporation.

Clever. Never thought to do that.

[travelin texans]

Originally Posted by slow

Pour enough mineral oil into the drains after winterizing to create an oil film on top of the antifreeze. It prevents evaporation.

Not necessarily just winterizing, but would at least once a year, usually more, would add 1/4-1/2 cup of cheap dollar store vegetable oil into all the drains to help lubricate the drain valves.

[Camp CA]

Try adding Unique https://uniquecampingmarine.com/blog...tank-treatment OR this solution:

• Use a clean, empty one-gallon plastic jug or bottle
• Measure 40 ounces of Pine-Sol (or similar pine oil cleaner) into the jug or bottle
• Add eight ounces of Calgon bath powder, liquid, or bath beads to the jug or bottle
• Slowly add water to the jug or bottle. The contents will foam, so be patient.
• Put the cap on the jug or bottle and shake
• Every time you’ve emptied your holding tanks, add 1/2 cup of this solution

[travelin texans]

Originally Posted by Camp CA

Try adding Unique https://uniquecampingmarine.com/blog...tank-treatment OR this solution:

• Use a clean, empty one-gallon plastic jug or bottle
• Measure 40 ounces of Pine-Sol (or similar pine oil cleaner) into the jug or bottle
• Add eight ounces of Calgon bath powder, liquid, or bath beads to the jug or bottle
• Slowly add water to the jug or bottle. The contents will foam, so be patient.
• Put the cap on the jug or bottle and shake
• Every time you’ve emptied your holding tanks, add 1/2 cup of this solution

I would not recommend this solution in the black tank! That tank odor is bad enough, but pine scented s##t smell is worse, smells like you been eating pine cones.
Nor would I recommend bleach in any of the tanks or risk damage to valve seals.
Typically any product that claims to digest waste needs to be in the tank for an extended period of time, not overnight. Read the label on RidX, use every 30 days. You do not have a septic system on your rv, you have holding tanks. I'm sure parks that have septic systems will appreciate you adding those products to their system.

[Camp CA]

Should have clarified to use Pine-Sol Lemon Fresh and Ocean Breeze Calgon Ultra-Moisturizing Bath Beads. The recipe came from http://rvholdingtankservices.com/faq/. Reported benefits are: sanitizing your tanks while creating a slippery coating to help your sensors remain free of blockage.

[Dacheedah]

https://www.youtube.com/watch?v=E731e8asMyI

[Weldon]

I use borax, water, and either ZEP concentrate or Totally Awesome from Dollar General between trips. Dawn works too. I just put 5 gallons total in each tank between trips (assuming the next trip is less than a month). Traveling with that mixture cleans while driving and I empty tanks as normal at camp site. Smells good and seems to clean well. You can check out the bio method by TR Bowlin.

https://www.trbowlin.com/bio-geo-method/