Avraham, Yitzchak, and Yaakov shared an apartment. For the first few months, they shared all the expenses, including utilities, evenly.
During the year, Avraham got a new job. He had to work long hours and often traveled; he spent little time in the apartment. Yitzchak, on the other hand, began working from home and spent a lot of time there during the week, but was rarely there for Shabbos. Yaakov took a job as an assistant rabbi in the local shul, and began staying for Shabbos on a regular basis. He liked cooking, and would often invite other singles from the community to join him for Shabbos meals.
“I don’t think I should be paying an equal amount anymore,” Avraham said. “You two use the apartment much more than I do. We should divide the rent and other bills proportional to our use.”
“It’s not our problem that you aren’t around,” argued Yitzchak. “We rented the apartment as partners and should split all the associated costs, as we did until now. You’re welcome to use the apartment as much as you want.”
“I agree with Yitzchak about the rent,” said Yaakov. “Either you’re a partner in the apartment or not. However, I think that other expenses, like the electricity, should be divided by each person’s use. Since Yitzchak is here a good part of the day, he should carry more of the burden.”
“And what about the gas and water?” retorted Yitzchak. “You cook more than anyone else, and like to take long showers twice a day!”
The three continued to argue and could not come to a resolution. “Perhaps we should turn to Rabbi Dayan,” suggested Avraham.
Yitzchak and Yaakov agreed. .
The three came before Rabbi Dayan. Avraham described the situation and asked: “How should we divide payment of the rent and various bills?”
“Despite the fact that Avraham uses the apartment less,” answered Rabbi Dayan, “the rent should certainly be divided equally. Regarding the other bills, if you can’t come to an agreement, you should share them also equally.”
“Why is that?” asked Avraham.
“Partnership is determined by the rights of usage, not the actual usage,” explained Rabbi Dayan. “Thus, although Avraham uses the apartment much less, he is still an equal partner. He has equal rights of usage, although he does not exercise them, and therefore has equal responsibility for the rent.”
“What is the source for this?” asked Yitzchak.
“The Gemara [B.B. 13a] addresses the case of two children, one wealthy and one poor, who inherited an olive press intended for personal use,” replied Rabbi Dayan. “Although the wealthy brother uses the olive press much more, the poor brother cannot demand payment for the unequal usage. The wealthy brother can say, ‘Purchase olives and use the press.’ ”
“What about expenses that relate to actual usage?” asked Yaakov. “For example, electric, gas, and water bills that are direct result of usage?”
“It is logical that, in principle, these should be divided based on usage,” replied Rabbi Dayan. “However, since it is difficult to determine this exactly, and the usage varies over time depending on circumstances, it is common to divide the amount equally for the sake of convenience.”
“Furthermore, some authorities indicate that in principle these expenses also should be divided equally, so long as the partner use the service occasionally,” continued Rabbi Dayan. “For example, sharing the costs associated with a communal mikveh, cleaning of a communal toilet, or running an elevator in an apartment building.” (See Chasam Sofer O.C. #193; Emek Hamishpat, Shecheinim #41,44-45)
“Anyway, we initially agreed to divide these costs equally,” pointed out Yitzchak.
“For the duration of the partnership, the agreement is binding,” said Rabbi Dayan. “However, when you renew the contract, Avraham can negotiate with you regarding the expenses based on the new circumstances.” (C.M. 176:16-17)