You can submerge the hose as long as it's not for a prolonged period of time. 30 minutes to 1 hour would be long enough. In you bathtub mix up a solution of household bleach and tepid water. Formula is 1 part bleach to 3 parts water. Submerge the hose completely except for the plastic connection end(s)... You may need to put something over it to keep it underwater. Once the soaking is over take it outside (if it's not too cold where you are) and flush it with a hose. Inside and out.. If this can't be done empty the tub and fill will clean cold water. Submerge the hose then drain it two or three times. After the hose has been cleaned lay it out somewhere to completely dry before using.
Dennis (cut2it)
C&onstructi&on C&onsultant
Over 40 yrs. as General Contractor for new const. & remodel - retired with time for you.