Pardon if this has been covered before but I found nothing in the search function. When dumping and then flushing the holding tank, we are getting serious sewer odors inside our 5er. This odor is really bad during the flush. We have tight connections and no leaks anywhere. We don't usually get odors inside if I do not flush the tank. I have water in the P-trap for the W/D connection. I can't figure where the odor is coming from or how to prevent it during the flush out.Comments, suggestions?Joe

I just put up with it. It goes away quickly.

If you have your A/Cs on when dumping/flushing, it can pull the vent odors inside.

Your A/C or your bathroom fan - the bathroom fan should always be off when dumping anyway! Toss one of those rank deodorizer packets down there after you've dumped and filled the black tank w/ a few gallons of water. Then, wait out the smells like the 2nd poster suggested.

They grey tank water can smell really bad. Try this to see if the problem is grey tank odor. Before dumping close drains in all sinks and tub. Put a little water in the sinks. Dump. The dumping of the water could be siphoning water out of one of the traps. No odor then you have the cure. ODOR then it is the black tank.

You may need to replace the air admittance valves. If they are not functioning properly they will let sewer/grey odor in. They are cheap and can be purchased in the plumbing section at Lowe's, Menards, Home Depot, or hardware stores. They are usually found under the sinks and we also have one in the plumbed area for washer/dryer. Your main vent could also be plugged causing this.

Sewer odors | Good Sam Community

2oldman
Explorer II
Dec 09, 2017
I just put up with it. It goes away quickly.
accsys
Explorer
Dec 09, 2017
If you have your A/Cs on when dumping/flushing, it can pull the vent odors inside.
FrankShore
Explorer
Dec 09, 2017
Your A/C or your bathroom fan - the bathroom fan should always be off when dumping anyway! Toss one of those rank deodorizer packets down there after you've dumped and filled the black tank w/ a few gallons of water. Then, wait out the smells like the 2nd poster suggested.
darsben1
Explorer
Dec 09, 2017
They grey tank water can smell really bad. Try this to see if the problem is grey tank odor. Before dumping close drains in all sinks and tub. Put a little water in the sinks. Dump. The dumping of the water could be siphoning water out of one of the traps.
No odor then you have the cure. ODOR then it is the black tank.
doxiemom11
Explorer II
Dec 09, 2017
You may need to replace the air admittance valves. If they are not functioning properly they will let sewer/grey odor in. They are cheap and can be purchased in the plumbing section at Lowe's, Menards, Home Depot, or hardware stores. They are usually found under the sinks and we also have one in the plumbed area for washer/dryer. Your main vent could also be plugged causing this.
jpjulian
Explorer
Dec 09, 2017
darsben1 wrote:
They grey tank water can smell really bad. Try this to see if the problem is grey tank odor. Before dumping close drains in all sinks and tub. Put a little water in the sinks. Dump. The dumping of the water could be siphoning water out of one of the traps.
No odor then you have the cure. ODOR then it is the black tank.

It's not the grey tank. The nasty odors only occur during flushing of the BLACK tank.

Joe
jpjulian
Explorer
Dec 09, 2017
doxiemom11 wrote:
You may need to replace the air admittance valves. If they are not functioning properly they will let sewer/grey odor in. They are cheap and can be purchased in the plumbing section at Lowe's, Menards, Home Depot, or hardware stores. They are usually found under the sinks and we also have one in the plumbed area for washer/dryer. Your main vent could also be plugged causing this.

The admittance valves deal with the grey tank. My issue only occurs when flushing the BLACK tank.

Joe
jpjulian
Explorer
Dec 10, 2017
FrankShore wrote:
Your A/C or your bathroom fan - the bathroom fan should always be off when dumping anyway! Toss one of those rank deodorizer packets down there after you've dumped and filled the black tank w/ a few gallons of water. Then, wait out the smells like the 2nd poster suggested.
\

I may have to address the a/c or fan issue when I next dump. It has been fairly warm here the last number of days and we likely had the a/c fan and the Fancy Fan running. This seems to be a recent issue opposed to a long term problem so looking at the fans as the problem may be the ticket.

Joe
Mike_Taverniti
Explorer
Dec 10, 2017
I agree with the Air Admittance Valve ( Mechanical Plumbing Vent ) failure. You need to replace and always keep a few spares. About $ 6 each at Lowes.
beemerphile1
Explorer
Dec 10, 2017
FrankShore wrote:
Your A/C or your bathroom fan - the bathroom fan should always be off when dumping anyway! Toss one of those rank deodorizer packets down there after you've dumped and filled the black tank w/ a few gallons of water. Then, wait out the smells like the 2nd poster suggested.

An RV A/C unit does not draw in outside air, it only circulates the inside air repeatedly.

Forum Discussion

Sewer odors

About RV Tips & Tricks

Related Content

sewer odor

VERY strong sewer odor

Sewer odor when towing

ODOR WON'T GO AWAY

Sewer odor, help please