So I just moved to Missouri from California. The house I got was built in 1915.... When I was in the basement (really more of a storm shelter) I noticed a problem (imo). The drain pipe the washer drain is on, has a p trap and a hose (see pics). When the washing machine drains, I can hear water flowing past the problem area, however water still comes out of the black hose. Is this hose necessary? Is this a problem? Was this put to flush the pipes with pressure?