The RO residential open space district is designed to promote and encourage the orderly development of steep hillside areas of the city by the application of regulations and requirements established to meet the particular problems associated with the development of steep hillside areas.
(Ord. 485 § 3.01, 1971)
In the RO district the following buildings and uses are permitted as hereinafter, subject to the general provisions and exceptions set forth in this chapter and regulations set forth in Chapters 20.01, 20.08 through 20.24, 20.68 and 20.72 PMC:
A. 
The following accessory buildings and uses, which are incidental to the uses permitted in this chapter:
1. 
Carports or garages for the sole use of occupants of premises and their guests, attached or detached (without fee to guests), for storage of motor vehicles, boats, recreational vehicles and/or planes;
2. 
Greenhouse, private and noncommercial;
3. 
Storage buildings for yard maintenance equipment and household goods; and
4. 
Recreational facilities for private use;
B. 
Public buildings essential to the economic welfare of an area. Rear and side yards for these uses shall be a minimum of 25 feet in width. No stockpiling or storage of materials shall be allowed;
C. 
Single-family dwellings;
D. 
Adult family homes; and
E. 
Family day care.
(Ord. 485 § 3.02, 1971; Ord. 1952 § 6, 2017)
The city may grant a conditional use permit (CUP) for the following buildings and uses in accordance with the procedures set forth in Chapter 20.20 PMC:
A. 
Libraries;
B. 
Permanent supportive housing (shall conform to Chapter 20.96 PMC – Multifamily Housing Design Standards) (see PMC § 20.68.200 for applicable regulations);
C. 
Transitional housing (shall conform to Chapter 20.96 PMC– Multifamily Housing Design Standards) (see PMC § 20.68.200 for applicable regulations); and
D. 
Any other buildings or uses determined to be similar to those listed in PMC § 20.36.020. Such other uses shall not have any different or more detrimental effect upon the adjoining neighborhood areas or landscape than the specifically permitted buildings and uses.
(Ord. 485 § 3.03, 1971; Ord. 1170 § 1, 1992; Ord. 1505 § 11, 2001; Ord. 2053 § 3, 2022)
The excavation, processing and removal of soil, peat, sand, gravel, rock (which may include the crushing thereof) or any other natural deposits of commercial value is prohibited in the RO district.
(Ord. 485 § 3.04, 1971)
The following minimum requirements shall be observed, except where increased for conditional use:
A. 
Lot area, one acre;
B. 
Lot width, 120 feet;
C. 
Front yard, 60 feet from center of road right-of-way;
D. 
Rear yards, 30 feet. Where a utility easement is recorded adjacent to a rear lot line, the yard shall be no less than width of the easement on the development site;
E. 
Side Yards. All lots or development sites in the RO district shall have side yards of not less than 10 feet, except that where a utility easement is recorded adjacent to a side lot line, there shall be a side yard no less than the width of the easement.
(Ord. 485 § 3.07, 1971)
Corner lots shall observe the minimum front yard setback requirements on one street side. One-half the minimum setback requirement shall be observed on the second street side.
(Ord. 485 § 3.09, 1971)
Only the following signs are permitted, subject to the following limitations:
A. 
Nameplates not exceeding three square feet in area, containing the name and/or address of the occupant of the premises;
B. 
One unlighted sign not exceeding six square feet in area pertaining only to the sale, lease or hire of only the particular building, property or premises upon which displayed, and for no more than three months.
(Ord. 485 § 3.10, 1971)
All uses shall conform to the general provisions and exceptions set forth in Chapter 20.72 PMC, Parking and Loading.
(Ord. 485 § 3.11, 1971)