Big loads only, doesn't seem to be the hoses in back, could it just be the drain in the basement floor that needs some drano down?  I am tired of things leaking, just got the water heater replaced for a big leak there, went down after laundry, and a pool back in front of the washer! Tried it again with a large load instead of extra large, smaller pool, but still there.  Currently doing a medium load.

Could there be a kink in your hose? My sister had this problem out of nowhere and it turned out to be a kink. Whatever it is I hope is a simple inexpensive solution.

We had the same problem recently.  It took the repairman a long time to find the problem.  It turned out to be a gasket around the top of the tub.  You might try checking that.

 Thanks for info.  Will check.

What about the water pipes themselves? This just happend here and We had to put in new pipes

 Sea Hound-that sounds too expensive!  I wonder if it's just backing up at the floor drain.  There is a glass ball on the drain, I'm assuming to keep crud out.  Can I put drano down it?  Or around it, or however you treat a floor drain?