I can see water in kitchen sink drain even though grey tank is not full.

[Elaina]

We just purchased a RBS30 and when I use the kitchen sink I notice that when water drains it sits right at the drain level (I can see it) even though the grey tank is not full. It hasn't caused a problem that I'm aware of but it seems odd. Have I done something wrong?

[howson]

We just purchased a RBS30 and when I use the kitchen sink I notice that when water drains it sits right at the drain level (I can see it) even though the grey tank is not full. It hasn't caused a problem that I'm aware of but it seems odd. Have I done something wrong?

The shower drains into the same gray tank on your 30RBS Transcend. Does the shower drain quickly without any issues?

If the shower also drains very slowly, the issue may be related to the vent.

If the shower drains fine, there may be an issue specifically with drain in the kitchen sink. If there's a "P" trap, maybe there's debris in the line?

Honestly I'm not much of an expert when it comes to plumbing. Others will be along shortly (including Cate&Rob ) who hopefully can help.

Howard

[Cate&Rob]

Elaina
Hi Elaina . . . welcome to our owners technical forum.

Under the counter beside the sink is a vertical extension of the drain pipe leading up to an “Air Admittance Valve” (AAV for short). This valve is supposed to open to let the water in the drain drop to the normal level in the P trap (that you should not be able to see). I think your AAV might be stuck shut. This valve is typically only hand tight. Try loosening/removing this valve to see if this drops the water level in the sink drain. (Don’t leave it out . . . this could cause a flood under the sink!). If this solves the problem, these valves are available at Home Depot or similar.

Rob

[Yoda]

We just purchased a RBS30 and when I use the kitchen sink I notice that when water drains it sits right at the drain level (I can see it) even though the grey tank is not full. It hasn't caused a problem that I'm aware of but it seems odd. Have I done something wrong?

Could you be seeing water in the P-trap.Its a U shaped pipe that holds water so sewer gas does not pass though the sink piping. Look under the sink and see how close it is plumed. A picture would be even better.