Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 10, 2025 ...

BLACK TANK ODOR

November 11, 2018, 11:16:22 am

We have a SensaTank RV 100 system, installed by PO, to monitor our tanks, which seemed to work ok when we bought the coach. Now, there is an odor coming from the black tank, when it only reads 1/2 full. We also notice that the gray tank starts " gurgling" in the shower base, also when the meter reads 1/2 full. I had issues with incorrectly installed vent pipes, in our travel trailer, so my thoughts drift towards a venting problem. I have no idea of what, how....to remedy the situation. Thanks for any help.

Quote Selected

Re: BLACK TANK ODOR

Reply #1 – November 11, 2018, 11:25:32 am

Yes, check the vents for obstructions (like insect nests).

Also, check air admittance valves (under sinks).  They are a common failure and cheap/easy to replace.

Quote Selected

Re: BLACK TANK ODOR

Reply #2 – November 11, 2018, 12:33:18 pm

I have always found when the "gray tank starts  gurgling in the shower base," the tank IS actually full.

The sensor readings  are likely not correct.  Many of us have installed the "see level" system to fix the issues.

I also agree check air admittance valves (AAV).

This thread will show where I found the AAVs on our coach: Sewer Odor, roof sewer vent, air admitance valves inside...

Quote Selected

Re: BLACK TANK ODOR

Reply #3 – November 11, 2018, 01:32:04 pm

Glenn, possible they installed sensors on top half of tanks, possible AAV valve(s).

Quote Selected