Spilling out all drawn water in the vicinity when a person passes away:
It is customary to spill out all the drawn water in the neighborhood in which the person passed away. [Water of the neighborhood should be spilled even if a child, who is less than thirty days old, passes away, and even if a gentile passes away. On Shabbos, one is not to spill the water. However, on Yom Tov one is required to do so. One is not required to spill out water that was frozen at the time of death. One is only required to spill out plain water and not other water based liquids. One is not required to spill undrinkable water. Some Poskim rule one is not required to spill out water that was covered tightly. However, others rule that even sealed water is required to be spilled, and so is implied from Admur.]
Definition of neighborhood: Some Poskim rule a neighborhood is defined as three houses [or apartments]. [This refers to the two houses that are closest to the house of the deceased, as well as the actual house of the deceased. This includes the two closest houses on each side of the house of the deceased [i.e. two houses square].] Other Poskim however rule that only the [house of the deceased and the] actual [next door] neighbor must spill the water, and so is the custom. [According to all, we follow the area the person was in at the times of death and not his home or place of origin, even if he was brought to that location later on. Thus, if the person passed away in a hospital, his neighbors by his house do not need to spill the water. However, the hospital rooms near the room of the deceased are to spill their water. If there is a street that separates between the houses of the deceased and a neighbor’s house, the neighbor is not required to spill the water.]
Already said a blessing: If one said a blessing over the water and then heard that a person passed away in the neighborhood, and the custom is to spill out all of the drawn water in the neighborhood of the person who passed away, then he is to swallow a sip of water in order so it not be a blessing in vain, and then spill out the remainder of the water.
Water of Mayim Shelanu: One who has drawn water in his home, which was drawn for the sake of kneading the Matzos [i.e. Mayim Shelanu], and a person in the neighborhood passes away in which case one needs to spill out all the water in the neighborhood due to worry of danger, nevertheless, one is not required to spill out these waters. Nevertheless, if one wants to be stringent and spill them out, then he may do so. Furthermore, one is even encouraged to do so if one can easily find other water for Mayim Shelanu, or if he can easily delay kneading the Matzos until another day with other water which she will draw during the twilight before. Nevertheless, this only applies to the waters which were drawn for the sake of the Matzos which are not eaten for the sake of the Mitzvah, as this is close to being voluntary being that one has the choice not to eat Matzah throughout the entire Pesach [aside for the first night]. Accordingly, it is permitted for him to be stringent on himself and spill out the water. However, water that was drawn for the sake of kneading the Matzos Mitzvah, it is not proper for him to be stringent upon himself and to spill out the water even if he can easily find other water, as it appears like he is belittling the words of the verse, “one who guards a Mitzvah knows no evil.” Nevertheless, initially one should not rely on this and prior to the arrival of the Tekufa he should place a piece of metal inside the water.
When a person passes away, all the plain water that is in that house [i.e. water bottles, cups and buckets of water] is to be spilled. Likewise, the neighbors of closest proximity to that home are to also spill their water. On Shabbos, no water is to be spilled.
May the water be used for non-eating purposes?
Some Poskim rule that the water which is meant to be spilled may not to be used for any purpose. Other Poskim, however, rule it may be used for non-eating purposes, such as for laundry and bathing.
If one mixed the water with other foods, may the food be eaten?
Some Poskim the food is forbidden to be consumed even if it contains 60x the water. However, if it was used for the Shabbos food, it may be eaten. Other Poskim, however, rule the food may always be eaten.
Must the water be spilled after a Nefel [i.e. still born, or baby who died within thirty days] passes away?
One is to spill the water in the home after a Nefel passes away. However, if the child was born dead, water is not needed to be spilled.
Must ice be spilled out?
No, unless it only became ice after the death occurred.
 Michaber Y.D. 339:5; Rama O.C. 455:1; Admur O.C. 206:14; 455:15; Kol Bo; Mordechai Remez 593; See Gesher Hachaim 3; Sefer Shemiras Haguf Vihanefesh [Lerner] 186:1
Other opinions: In many communities, it is no longer customary to spill the water after the death of someone in the neighborhood. [See Sefer Shemiras Haguf Vihanefesh [Lerner] 186:1 footnote 2] Some Poskim rule that one may be lenient in a case of loss. [Beis Yitzchak Y.D. 2:103; Divrei Malkiel 4:94; Har Tzevi Y.D. 261; Sdei Chemed; Yabia Omer 1 Y.D. 23; Sefer Shemiras Haguf Vihanefesh [Lerner] 186:5]
 The reason: Several reasons are given behind this custom: a) There is danger involved if one does not spill the water. [Admur ibid and ibid] as the angel of death places a drop of poisonous blood into the water, and one who drinks from it endangers his life. [Admur 206:14; Taz 339:4-only reason; 2nd reason in Shach 339:9; Tashbatz 444; Kol Bo 114; Mordechai Remez 593; Olas Tamid 206:5 that so is main reason; Levush 455:6; Kaf Hachaim 206:45] The Tashbatz writes that a person once drank this water and died shortly afterwards. [Shach ibid; See Beir Heiytiv 339:5 for full story] b) This is done to publicize that there is a death and prevent the need of verbally informing people, as one who informs another of a death is considered to be “spreading evil tongue.” [1st reason in Shach ibid; Maharil] See Mavor Yabok Sefas Emes 23; Damesek Eliezer 49
 Birkeiy Yosef 339:8, brought in Pischeiy Teshuvah 339:4, Rav Akiva Eiger 339; Yad Avraham 339; Poskim in Nitei Gavriel 8:7-8 footnote 11 and 15; See Sefer Shemiras Haguf Vihanefesh [Lerner] 186:9-10
Other opinions: Some Poskim rule it is not necessary to spill the water. [See Poskim in Nitei Gavriel 8:7-8 footnote 12 and 16]
 Shemesh Tzedakah Y.D. 36; Tosfos Shabbos 211:1, brought in Rav Akiva Eiger 339; Pischeiy Teshuvah 339:4; Aruch Hashulchan; Sefer Shemiras Haguf Vihanefesh [Lerner] 186:7 footnote 7
The reason: As we do not publicize a death on Shabbos, as well as that the angel of death does not enter his sword in the water on Shabbos. [ibid]
Other opinions: Some Poskim rule one is to spill the water even on Shabbos. [Birkeiy Yosef; Pischeiy Teshuvah 339:4 says to spill after Shabbos; Sefer Shemiras Haguf Vihanefesh [Lerner] 186:7]
 P”M 455 M”Z 3; Poskim in Nitei Gavriel 8:6 footnote 9; See Sefer Shemiras Haguf Vihanefesh [Lerner] 186:8
Other opinions: Some Poskim rule it is not necessary to spill the water on Yom Tov. [See Poskim in Nitei Gavriel 8:6 footnote 9-10]
 Chamudei Daniel, brought in Pischeiy Teshuvah 339:5
 Beis Yitzchak Y.D. 50; Maharsham 3:375; Poskim in Nitei Gavriel 8:3 footnote 4; Sefer Shemiras Haguf Vihanefesh [Lerner] 186:4
 Tuv Taam Vadaas Tinyana 279; Halef Lecha Shlomo Y.D. 316; Sefer Shemiras Haguf Vihanefesh [Lerner] 186:3
 See M”A 455:9; Darkei Moshe 455:7; Beis David 181; Nitei Gavriel 8:16
 See Nachamu Ami p. 17
 Admur 455:16 omits ruling of Darkei Moshe and M”A ibid regarding covered, and even in the case of placing metal Admur explicitly writes it regarding the Tekufa; Likewise, see Admur in Shemiras Hanefesh Vehaguf Halacha 7 regarding food under the bed that it is problematic even if covered.
 See Sefer Shemiras Haguf Vihanefesh [Lerner] 186:12
 Taz 339:4 based on Tosafos Kesubos
 Chamudei Daniel, brought in Pischeiy Teshuvah 339:6
 In an apartment building, this would include up to two floors above and below the apartment of the deceased. [See Poskim in Nitei Gavriel 8:12 footnote 24
 Gilyon Maharsha 339; Poskim in Nitei Gavriel 8:11 footnote 23
 Nekudos Hakesef 339; Beir Heiytiv 339:5
 See Nitei Gavriel 8:2
 Nitei Gavriel 8:13 in name of Tuv Tam Vadas 1:102 and other Poskim
 Admur 206:14; M”A 206:8; Sefer Chassidim 851; Olas Tamid 206:5; Kneses Hagedola O.C. 204, brought in Rav Akiva Eiger 339; Ely Raba 202:1; M”B 206:26; Kaf Hachaim 206:45; Sefer Shemiras Haguf Vihanefesh [Lerner] 186:15
 The reason: Even according to those opinions who say that the reason for the custom of spilling out the water in the neighborhood of the person who passed away is because the angel of death places a drop of blood of death into the water, and one who drinks from it endangers his life, nonetheless, [the verse in Koheles 8:5 states that] one who guards a Mitzvah will know no evil. Nonetheless, once one has already drank a little from it and accomplished that his blessing is no longer in vain, then he is to pour out the rest of it due to this worry danger. [Admur ibid]
 Admur 455:15; Rama 455:1; Shach 339:9; Mordechai Remez 593; Rokeiach 275; Bach 455; Levush 455:6; Sefer Shemiras Haguf Vihanefesh [Lerner] 186:6
 Admur ibid; Rama ibid; Mordechai ibid; Beis Yosef 455
The reason: As the verse [Koheles 8:5] states “One who guards a Mitzvah will know no evil” [Admur ibid; M”A 455:7; Taz 455:3; Levush 455:6; Rebbe Yehuda Hachassid; Mordechai ibid]
 Admur ibid; Taz 455:3; Chok Yaakov 455:7
Other opinions: Some Poskim rule
 Admur 455:16; Taz 455:3; Chok Yaakov 455:7; Kaf Hachaim 455:34
 Admur ibid; Rama 455:1; Maharil p. 34; Minhagim Tirana Erev Pesach p. 35
 See Sefer Shemiras Haguf Vihanefesh [Lerner] 186:14
 Adnei Paz 26, brought in Pischeiy Teshuvah 339:4; See Poskim in Nitei Gavriel 8:20
 Pischeiy Teshuvah 339:4; See Poskim in Nitei Gavriel 8:20
 See Sefer Shemiras Haguf Vihanefesh [Lerner] 186:13
 Teshuvas Beis Yehuda Y.D. 1:46, brought in Rav Akiva Eiger 339; Birkeiy Yosef 339; Beis David 161; Pischeiy Teshuvah 339:4; Gilyon Maharsha 339; Yad Avraham 339; See Poskim in Nitei Gavriel 8:19 footnote 33
 Pischeiy Teshuvah ibid; Sefer Shemiras Haguf Vihanefesh [Lerner] 186:6
 Aruch Hashulchan 339:9; Poskim in Nitei Gavriel 8:19 footnote 34
 Nitei Gavriel 8:7; 135:7
 Chamudei Daniel, brought in Pischeiy Teshuvah 339:5; Sefer Shemiras Haguf Vihanefesh [Lerner] 186:2