Besides the obligation of Netilat Yadayim that applies before one eats bread, there are a number of other occasions which require one to wash his hands. The Ben Ish Hai (Rav Yosef Haim of Baghdad, 1833-1909), in Parashat Toldot (16-17), identifies two separate categories: situations requiring hand washing because of a "Ru’ah Ra’a" – "spirit of impurity" – which descends upon the hands, and those requiring hand washing due to hygiene concerns. When washing is required simply for hygienic purposes, to remove filth, the Ben Ish Hai writes, then it suffices to simply run one’s hands under the faucet. But when washing is required to remove a "Ru’ah Ra’a," then one must wash his hands from a utensil, and wash each hand three times in alternating fashion.
The Ben Ish Hai lists the following situations are requiring washing to remove a "Ru’ah Ra’a":
1) Waking up in the morning. This is the only situation (besides eating bread) when a Beracha is recited over hand washing.
2) Leaving a restroom. Even if one did not perform bodily functions, he must wash his hands anytime he enters the restroom, because the restroom itself is a place of impurity. (For this reason, it is preferable to have a sink accessible outside the restroom, and to wash there.)
3) Marital relations. Both the husband and wife should wash their hands after marital relations.
4) Leaving a cemetery or a funeral. It is customary not to dry one’s hands after washing them upon leaving a cemetery, and the Ben Ish Hai explains that this is done so that one will remember that he had just been in a cemetery. In cold conditions, when leaving one’s hands wet could result in illness, it is certainly permissible to dry them.
In all these situations, one must wash three times in alternating fashion, from a utensil.
The Ben Ish Hai writes that leaving a bathhouse, shower or Mikveh requires hand washing because of a "Nidnud Ru’ah Ra’a" – "mild" spirit of impurity, and therefore, it suffices to simply run one’s hands once under water. This applies also to cutting one’s nails, unless the nail had grown beyond the flesh – which is usually when one cuts his nails – in which case removing them brings a full-fledged "Ru’ah Ra’a" that requires washing three times. Regardless, the Ben Ish Hai writes that it is proper to be stringent and wash three times from a utensil in these situations, as well.
The following situations require washing for the purpose of cleanliness, and thus do not require washing three times or from a utensil:
1) Touching shoes. If one touched the laces but did not touch the shoes, or if he touched brand new shoes which had never been worn, then washing is not required.
2) Touching parts of the body which are normally covered. This includes one’s stomach and back, and the upper arm, above the elbow. Men who touch the upper part of the arm upon which they place Tefillin do not need to wash.
3) After taking a haircut. However, although strictly speaking, any washing suffices after taking a haircut, nevertheless, the common practice is to wash three times from a utensil after taking a haircut.
Summary: The following situations require washing one’s hands three times in alternating fashion, from a utensil: upon waking in the morning, after leaving the restroom (even if one did not perform his bodily functions), after marital relations, after leaving the cemetery or a funeral, after bathing in a shower or a Mikveh, and after nail cutting. The following situations require any sort of hand washing, even simply running one’s hand under water: touching shoes, touching parts of the body that are normally covered, including the back, stomach and upper arm (except the upper arm where one wears Tefillin), and taking a haircut. It is nevertheless customary after taking a haircut to wash three times from a utensil. A Beracha is not recited in any of these situations, with the exception of waking in the morning.
