Septic odor from washer machine drain
 

I have a septic system that is running properly however when my kids take a shower an odor is emitted from my washer machine drain. Is there a way to seal the drain making the drain air tight and still have a functional washer drain?

Is the line for the shower vented?
Sounds like it could be sucking air through washer stand pipe emptying out the trap :)

I'll assume your washing machine drain is a standpipe which your hose is stuck into. You can't seal that connection because air needs to flow around the hose to break any siphon action which could occur and would drain your washing machine when it's supposed to be filled. Is this a newe issue or was it always like this? There should be a trap at the standpipe which would prevent any sewage smell from coming from the pipe.

That drain is suppost to have a trap in the line (may be behind the wall)
There is no trap then there's going to sewer gas going into the house.

as mentioned is this a new issue ..could be maybe lint building in line and shared with shower causing it to syphon trap???? no you should not seal off hose tight..