After one visits a cemetery, or attends a funeral in the presence of the deceased, he must wash his hands. Several Rishonim explain that washing is required due to the impurity that descends upon the hands in the presence of a deceased person. Therefore, one must wash his hands three times in alternating fashion, as only washing in this fashion eliminates the impurity. However, it is not necessary to wash with a utensil.
Other Rishonim understood this requirement as a matter of hygiene. In their view, being in the presence of a corpse, or in cemetery, results in some sort of filth on the hands, and this is the reason why washing is required. According to this understanding, one needs simply to run his hands once under the faucet. However, Hacham Ovadia Yosef ruled that one should abide by the stringent view, and wash his hands three times in alternating fashion after leaving a cemetery.
This requirement applies even if one visited a non-Jewish cemetery.
Most Poskim maintain that one is required to wash only if he was within four Amot (6-8 feet) of a corpse. This is the view accepted by Hacham Ovadia Yosef. Others, however, rule stringently, and require all who participated in a funeral procession to wash their hands, even if they did not come near the dead body. Rav Yisrael Bitan concluded that it is preferable to be stringent in this regard.
It is customary not to dry one's hands after washing following a funeral or upon leaving a cemetery. This practice is mentioned by the Kenesset Ha'gedola (Rav Haim Benveniste, Turkey, 1603-1673), though he writes that he does not know the reason. Other sources bring that this was the custom in the community of Yerushalayim. The Ma'abar Yabok (Rav Aharon Berechya of Modena, 1549-1639) explains this custom as intended to ensure that one does not easily forget the experience of attending a funeral. Attending funerals and visiting cemeteries has the effect of enhancing our awareness of our mortality, and so we leave the hands wet in order that the memory of this experience remains with us for an extended period of time. Somewhat similarly, the Ben Ish Hai (Rav Yosef Haim of Baghdad, 1833-1909) explained that we leave the hands wet in order that we do not quickly forget the deceased. In any event, Hacham Ovadia Yosef ruled – based on the Ben Ish Hai and others – that if it is very cold, and leaving the hands wet would cause a person great discomfort, he may dry his hands.
When people assemble by the sink at the cemetery to wash their hands, one should not hand the cup to the next person. Actively facilitating an act associated with the impurity of death is inappropriate, and is seen as a bad omen. Therefore, one should put down the cup after he uses it, rather than directly handing it to the next person. A similar Halacha applies to the shovel used when covering the grave with earth. It is customary that people take turns placing earth over the coffin, and when one finishes his turn, he should leave the shovel in the ground rather than hand it to the next person.
If one was unable to wash his hands after leaving the cemetery, he should not enter any building before washing his hands. Before stepping inside his home, he should ask somebody to bring him water outside. If, however, nobody is home, then he may walk inside and immediately wash his hands.
If one visits the burial site of Rabbi Shimon Bar Yohai in Meiron, the grave of Rabbi Meir in Teverya, or the graves of the patriarchs in Me'arat Ha'machpela, he does not need to wash his hands when he leaves. In all these sites, the Sadik is buried deep underground, or at a distance from the visitors' area, and so the visitors are not actually in the presence of the deceased Sadik. This applies also to other burial sites which are not precisely the spot where the Sadik is buried. Likewise, it is permissible to pray Shaharit, Minha or Arbit at these sites, whereas this is forbidden in a cemetery, so as not to appear as taunting the dead who are no longer able to pray or perform Misvot.
In truth, the Yalkut Yosef writes that it is customary in any event not to require hand-washing after visiting the grave of a great Sadik. Although Kohanim may not be present at the tomb of a righteous person, because even the remains of great Sadikim emit Halachic impurity, nevertheless, they do not emit the harmful impure forces that would normally necessitate hand-washing.
One should avoid frequent visits to cemeteries, so that one does not excessively expose himself to the impure forces that are present there. The Gaon of Vilna includes this warning in his list of instructions and admonition to his family.