Cleaning an area for davening

A person may not say a davar shebekedusha if he is either within four amos of mei raglayim or if it is in his line of sight (regardless of its distance). Since reciting a davar shebekedusha in front of mei raglayim is only forbidden mid’rabonon, Chazal were lenient and said that if at least a revi’is of water is poured over it and it is odor-free, the restriction is no longer in force. A revi’is of water is sufficient even if there is more than a revi’is of mei raglayim. The water should be poured in one shot. Otherwise, it will be incrementally nullified in the mei raglayim. Other liquids are also effective in nullifying mei raglayim.

סימן עז ס"ק א-ד ביאורים ומוספים דרשו, 6-5

How much water is necessary to clean an area?

As indicated above, a revi’is of water is sufficient to nullify mei raglayim even if it is the minority component of the mixture. If there is less than a revi’is of mei raglayim, only an equal amount of water is necessary to cleanse the area. If a revi’is of water was already used to nullify mei raglayim, the Rishonim disagree about whether it can nullify mei raglayim which is added to the mixture later. Shulchon Aruch rules according to the stringent opinion. The Achronim explain that according to both opinions, one revi’is of water can nullify numerous pourings of mei raglayim if the water is added afterwards.

סימן עז, סעיף ב וס"ק ז-ח

Must a catheter be covered in order to daven?

A davar shebekedusha may not be said in the vicinity of a chamber pot dedicated for mei raglayim. A patient who is connected to a catheter is permitted learn Torah and daven. The poskim disagree about whether the line and sack must be covered. Some say that it must be covered if it is made from rubber, and it is recommended to be covered if it is made of plastic. Others say that the sack should be covered but the line may be exposed. A third view holds that neither of them must be covered. They explain that since it is disposable, it is not comparable to the type of chamber pot which was common in the days of Chazal.

סימן עז, סעיף א וס"ק ה; סימן עח, ביאורים ומוספים דרשו, 3

• If one is in a location where tzoah is likely to be found, he must ascertain that the area is clean before saying a davar shebekedusha.

• A person who knowingly davened next to tzoah must daven again. If he was unaware of its presence and only noticed it afterwards, he only needs to daven again if he was in an area that was likely to contain tzoah and he was negligent by failing to check.

• A person may daven in a place even if he is not sure whether mei raglayim is present there.   

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