Avrumi Hersh asks:
81a the mekor that washing clothes is chiyus mamash, comes from the posuk about migreshey halviim, they were used for chayosom, and that must refer to washing. Does this mean that they used the space 1000 Amos outside of town to do their laundry? Isn't that strange, wouldn't they do it in town?
Avrumi Hersh , London england
The Kollel replies:
The Rishonim (see Rosh, for example) explain that the Gemara here understands the word "Migrash" means all places in the city that are not used for houses. One of these places are the water reservoirs of the city that are a kind of Migrash in that sense.
The Gemara says that the verse is referring to those reservoirs and says that laundry is a considered as Chayus more than other needs.
Kol Tuv,
Aharon Steiner