Willmar, Minn., Code of Ordinances ch. 6.5, art. II § 6.5-48

No person shall let to another for occupancy any rental unit, for the purpose of living therein, which does not comply with the requirements of this section. (1)
Every habitable room shall have at least one window or skylight facing outdoors provided that if connected to a room or area used seasonally (e.g., porch) adequate daylight must be possible through this interconnection.
(2) Every habitable room shall have at least one window or skylight facing directly outdoors which can be opened easily or such other device as will ventilate the room adequately, provided that if connected to a room or area used seasonally then adequate ventilation must be possible through this interconnection. When facilities for interior climate control (heating, cooling, and/or humidity) are integral functions of structures containing dwelling units or rooming units, such facilities shall be maintained and operated in a continuous manner and in accordance with the designed capacity of the installed equipment.
(3) Every bathroom and water closet compartment and every nonhabitable room used for food preparation shall comply with the light and ventilation requirement for habitable rooms contained in subsections (1) and (2) of this section, except that no window or skylight shall be required in such rooms if they are equipped with a ventilation system in working condition which is approved by the appropriate authority.
(4) Where there is usable electric service readily available from power lines which are not more than 300 feet away from a dwelling, every dwelling unit and all public and common areas shall be supplied with electric service, outlets and fixtures which shall be properly installed, shall be maintained in good and safe working condition and shall be connected to a source of electric power in a manner prescribed by the ordinances, rules and regulations of the city. The minimum capacity of such services and the minimum number of outlets and fixtures shall be as follows:
a. Every dwelling unit shall be supplied with at least one 15-ampere circuit and such circuit shall not be shared with another dwelling unit.
b. Every habitable room shall contain at least two separate wall type duplex electric convenience outlets or one such duplex convenience outlet and one supplied wall or ceiling type electric light fixture. No duplex outlet shall serve more than two fixtures or appliances.
c. Temporary wiring or extension cords shall not be used as permanent wiring.
d. All electric lights and outlets in bathrooms shall be controlled by switches which are of such design as shall minimize the danger of electric shock, and such lights and outlets shall be installed and maintained in such condition as to minimize the danger of electrical shock.
(5) Every public hall and stairway in every multiple dwelling shall be adequately lighted by natural or artificial light at all times, so as to provide in all parts thereof at least ten footcandles of light at the tread of floor level. Every public hall and stairway in structures containing not more than two dwelling units may be supplied with conveniently located light switches controlling an adequate lighting system which may be turned on when needed instead of fulltime lighting.