Clothes that get dirty frequently, such as those of babies and small children, may be washed on Ḥol Ha-mo’ed for festival use. The Sages prohibited washing clothes during Ḥol Ha-mo’ed in order to encourage people to wash them before the festival rather than wait. They did not include clothing that in any case would need to be washed during the festival. This laundry need not be done in private, as everyone knows that washing such clothes is permissible.
Nevertheless, one must wash all of the baby’s clothing and children’s clothing before the festival. Only after using up all the clean clothes may one wash whatever is necessary to get through the rest of the festival. If all of a child’s Yom Tov clothes are dirty, they may be washed even if he has clean weekday clothes. One must be careful not to throw in additional clothes for use after the festival. If one did not wash all the children’s clothing before the festival, many maintain that he may not do the laundry during Ḥol Ha-mo’ed, as it is considered as though he purposefully left this task for the festival. However, in practice, children should not suffer for their parent’s mistake. Therefore, be-di’avad one may wash the clothes that got dirty during the festival together with those which were not washed beforehand.
In general, children at age nine and up do not constantly get their clothes dirty, and thus their clothes may not be washed on Ḥol Ha-mo’ed. However, for those children who constantly get dirty when older, clothes may still be washed for festival use when they are nine or ten as well.
What about hand towels that are generally changed every day or two, and tablecloths that get dirty frequently? If they are all dirty on Ḥol Ha-mo’ed, they may be washed in a quantity sufficient to make it through the festival (SA 534:1). This is also the case for socks and underwear, which are generally changed daily on account of sweat. After all the clean ones have been used up, enough may be washed to get through the festival.