May an Ashkenazi Have a Sepharadi Wash His Clothes During the Nine Days?
Sephardic custom allows laundering clothes after Rosh Hodesh Ab. Whereas Ashkenazim refrain from doing laundry during the nine days from Rosh Hodesh Ab through Tisha B’Ab, Sepharadim forbid laundry only during "Shabua She’hal Bo," meaning, the week of Tisha B’Ab. Thus, when Tisha B’Ab falls on Sunday, as is the case this year (5772), there are no restrictions on laundry before Tisha B’Ab according to Sephardic custom. One may wash clothes the entire week before Tisha B’Ab, and laundry is forbidden only on Tisha B’Ab day itself. (On Shabbat, of course, laundry is in any event forbidden.)
The question was asked whether an Ashkenazi may have a Sepharadi wash clothes for him during the Nine Days. If a Sepharadi is doing a load of laundry during the week before Tisha B’Ab, as his custom allows doing, may his Ashkenazi friend bring some clothes to add to the load?
This question was addressed by Rav Haim Kanievsky (contemporary), who ruled (listen to audio recording for precise citation) that it is forbidden for an Ashkenazi to have his clothes washed by a Sepharadi during the Nine Days. Since he derives benefit from the laundering of his garments regardless who washes them, it is forbidden for him to have his clothes washed even by a Sepharadi.
Summary: On years when Tisha B’Ab falls on Sunday, Sepharadim may do laundry throughout the entire week before Tisha B’Ab, whereas Ashkenazim may not do laundry from Rosh Hodesh Ab until after Tisha B’Ab. An Ashkenazi may not have a Sepharadi wash his clothes for him during this period.