Related על ברכות 3:5

A man who had a seminal emission (Baal Keri) and is sick, if nine Kavs of water were poured on him, he may read [the Shema]. But he may not fulfill the obligation [of reading the Shema] for others until he dips himself in forty Seah [of water]. Rebbi Yehudah says, “Forty Seah no matter what."

One that was standing in the field naked or that was doing his work naked should cover himself with straw and with stubble or anything [else for that matter] and may read [the Shema]. Even though they (i.e. the Rabbis) said that it is not praiseworthy for a person to be sitting naked, because the Holy One Blessed Be He did not create man naked as it says, “I clothed him in a cloud and [made] mist his shroud.” (Job 38:9) “Clothed him in a cloud” that [refers to] the sack of the fetus, “and [made] mist his shroud” that [refers to] the placenta. [If] there was a wrap of cloth or of skin wrapped around his loins he may read [the Shema]. Either way he should not pray [Shmoneh Esreh] until he covers his heart.

[In order to say Shema or pray Shmoneh Esreh] a person must move away from the feces and urine of a small child who is capable of eating an olive size [piece of bread], four Amot. We only move away from [the feces] of a person and of a dog when skins are placed inside it (i.e. dog feces) [for processing].

[If] an [empty] vessel for excrement or a tub for urine is with him in the house, he should move away [from it] four Amot and read [the Shema]. [If it is] in front of his bed he should put any amount of water into it and read [the Shema], but if he did not [put water in it], he may not read [the Shema]. Rebbi Zakkai says, “If he put into it a Reviit of water he [may] read [the Shema], and if not, he [may] not read the Shema.” Rabban Shimon Ben Gamliel says, “[If the vessel for excrement] is in front of the bed he [may] not read [the Shema], [but] if it is behind the bed he [may] read [the Shema].” Rebbi Shimon Ben Elazar says, “Even if the whole house is approximately ten Amot [long] and the vessel for excrement is put inside it, he [may] not read [the Shema] until he takes it outside or puts it under the bed.”

A person should not go into dirty alleyways and read the Shema [there]. And not only that, but even if he already walked into [a dirty alleyway] while he was reading [the Shema], he should stop [reading it] until he completely exits from that area, and [only then] he [may continue] reading [the Shema]. A person should not stand and pray [Shmoneh Esreh] while he needs to relieve himself, as it is said, “Prepare to greet your God, Yisrael.” (Amos 4:12)

[A person] should not spill water [with feces in it] in a place where he [wants to] pray [Shemoneh Esreh], but rather he should [spill it] four Amot away [from that place]. If [the feces have] dried up or reabsorbed (i.e. dissolved) then it is permitted [to pray Shmoneh Esreh next to them].