Activities That Require Netilat Yadayim
Netilat Yadayim is a ritual washing of one's hands. It is requires at certain points during the day including waking up, before a meal, and before davening. For those halachot, see the following pages: Netilat Yadayim upon Waking Up, Netilat Yadayim for a meal, Netilat Yadayim in preparation for Davening. For any other washing, see the details below.
Which Activities Require Netilat Yadayim?
- One should wash netilat yadayim after one:
- goes to the bathroom,
- touches one's shoes,
- touches one's legs,
- touches an area that usually covered,
- scratches one's head,
- enters a cemetery. 
After Leaving the Bathroom
- The Shulchan Aruch (4:18) quotes from several rishonim that there is an obligation for one to wash netilas yadayim upon leaving a bathroom even if one did not relieve themselves. Many poskim hold no kli is necessary and neither is 3 times.
- The Gemara (Brachos 26a) describes a beis hakisei diParsai, which was a particularly clean bathroom because the waste would roll down to a pit a distance from the actual toilet, and therefore did not have some of the dinim of regular bathrooms. Modern poskim query whether our bathrooms should be treated like a beis hakisei diParai, and thus one would not require netilas yadayim upon exiting them, or not. The Chazon Ish (17:4) leaves this question in doubt, since unlike the bathrooms of the Parsai, in which the waste was removed immediately, our toilets hold the waste for a period of time until it is flushed away. Rav Shlomo Zalman Auerbach (Halichos Shlomo Tefilla 20:24), however, is lenient about this, and the Minchas Yitzchok (teshuva 1:60) concludes that in cases of need (bishas hadchak) one may be lenient not to wash upon leaving our bathrooms. Rav Schachter (Brachot Shiur 56 min 3-4) holds that there's no ruach raah in our bathrooms today.
- Ten Minute Halacha - Washing Hands After Bloodletting, and Cutting Fingernails, Hair by Rabbi Aryeh Lebowitz
- Yalkut Yosef 4:42
- Amongst them the Mordechai in Brachos (194)
- Pointed out by Mishna Brurah 4:40. See Halacha Brurah (Otzrot Yosef 1:12) who discusses this question at length and cites the Magen Avraham 227:2 who implies that there's no obligation of Netilat Yadayim for just entering a bathroom but the Zohar holds that there is.
- https://www.ou.org/torah/machshava/tzarich-iyun/tzarich_iyun_washing_after_leaving_the_washroom/ quoting Yalkut Yosef v. 3 p. 96. He points out that there is a stringency to wash with a kli outside the bathroom but washing with a kli in the bathroom is pointless.
- As the Rabeinu Yonah quotes from Rav Hai Gaon on the Gemara in Brachos
- Rav Ovadia Yosef (Yachava Daat 3:1) wasn't lenient to wash in a bathroom in the morning before a meal unless there was no other option. Yalkut Yosef 4:84 extends this ruling both to washing before a meal and in the morning. Orchot Rabbenu 1:12 writes that in practice Rav Ovadia Yosef himself did wash outside a bathroom whenever he had to do netilat yadyaim including the washing after going to the bathroom. See the footnote for the discussion of the halacha.