בור שבין שתי חצרות ואין ביניהם פתח או חלון שיוכלו לערב או שיש ביניהם ולא עירבו אין ממלאים ממנו בשבת אלא אם כן עשו מחיצה עשרה למעלה מן המים וצריך שיהיה טפח מן המחיצה יורד בתוך המים ואם הית' המחיצ' כולה בתוך המים צריך שיהי' טפח יוצא ממנה למעלה מן המים כדי שתהי' ניכרת רשות זה מרשות זה וכן אם עשו על פי הבור קורה רחבה ד"ט זה ממלא מצד הקורה וזה ממלא מצד האחר: הגה ודוקא אם בא למלאות בכלים של בית אבל בכלים של חצר לא בעינן שום תיקון דהא חצירות רשות אחת הן כדלעיל סי' שע"ב (הג"מ פט"ו):

Laws of a pit and well between two courtyards. Containing 4 paragraphs A pit between two courtyards where there is no opening or window through which they could make a joint eruv — or where there is one but they did not make an eruv — one may not draw water from it on Shabbat unless a partition ten hand breadths high was constructed above the waterline. A hand breadth of the partition must descend into the water. If the entire partition is within the water, a hand breadth must protrude above the waterline so that one domain is visibly distinct from the other. Similarly, if a beam four hand breadths wide was placed across the mouth of the pit, one resident draws water from one side of the beam and the other from the opposite side. Rema: This applies specifically when one comes to draw with vessels from the house. But with courtyard vessels, no such arrangement is needed, since courtyards are considered a single domain, as stated above in Siman 372.

A well situated in the middle of a pathway between two courtyard walls — even if it is four handbreadths distant from each wall — both residents may draw from it and need no projections above it, since no person restricts his neighbor through airspace. Rema: This applies specifically when the courtyards do not open into the pathway but only through windows. Some say that if the well is not four handbreadths from each wall, they do restrict one another even in this case.

Two courtyards with three ruins between them: each resident may use the ruin adjacent to his courtyard — through windows, by throwing — and the middle ruin may be used by both. If all three ruins were adjacent to houses such that the middle ruin faced the other two in the arrangement of three points of a tripod, each resident may use the ruin on his own side, but the third ruin — which is close to both courtyards — is forbidden to both.

An outhouse situated between two houses that did not make a joint eruv: both parties have jurisdiction over it and it is therefore forbidden to both. (See also above, Siman 355.)