Ice plug in Gray water tank?

[mercman]

I'm dry camping in my 2018 Jayco BWH286 with a Baja package. I have been using the bath room sink to brush my teeth and to irrigate my sinuses. Back in August I had opened the outside drain and got a good surge of gray water. I opened it this morning and just got a trickle. There have been a few Sub zero days so I think the system may be frozen somewhere. It's in the 40's for the next few days. Any opinions on whether I should let it sit or pour some hot water down the sink?

I did pour some water down the sink with no visible results.

[skids]

If it is a trickle, hot-ish water may open the dam. Be careful about adding too hot of a water temperature of you will damage the plastic P-traps, etc.

[mercman]

Thanks for the reply!

I was thinking last night that I'll try pouring a pot of warm salt water down the drain and see how that helps.