17-2-0300  Bulk and density standards.
   17-2-0301 Lot Area.
      17-2-0301-A Minimum Lot Area Standards. All development in R districts is subject to the following minimum lot area standards except as expressly allowed in Sec. 17-2-0301-B:
 
District
Minimum Lot Area*
(square feet)
RS1
6,250
RS2
5,000
RS3
2,500
RT3.5
2,500
RT4 to RM6.5
1,650
 
(*See Sec. 17-17-0302 for rules governing the measurement of lot area.)
      17-2-0301-B Exemptions.
         1.   Contextual Standard for RS1 and RS2 Districts. In the RS1 and RS2 districts, when more than 50% of similarly zoned lots on a block face have a minimum lot area per unit less than prescribed in Sec. 17-2-0301-A, the minimum lot area per dwelling unit standard will be established based on the predominant lot area of all zoning lots fronting on the block face. In no case, however, may the minimum lot area established pursuant to this contextual standard be less than 3,750 square feet.
         2.   Lots of record. A detached house may be established on any lot of record regardless of the size of the lot, provided that all other requirements of this Zoning Ordinance are met. This exemption also applies if a lot of record is increased in area and still does not comply with applicable minimum lot area standards.
      17-2-0301-C Exceptions. Any application seeking a zoning map amendment, pursuant to Section 17-13-0300, in order to establish a residential, day care, hospital, parks and recreation, school or outdoor assembly use that is proposed to be established within 660' of any (a) windrow composting facility, (b) intensive manufacturing, production and industrial service use, (c) Class III, Class IVA, Class IVB and Class V recycling facility, (d) warehousing, wholesaling, and freight movement use, (e) container storage, (f) freight terminal, (g) outdoor storage of raw material as a principal use, (h) waste-related use, or (i) manganese-bearing material operation use may be allowed only if further reviewed and approved in accordance with the special use procedures of Section 17-13-0900, unless it otherwise meets a planned development threshold of Section 17-8-0500.
   17-2-0302 Lot Frontage.
      17-2-0302-A Minimum Lot Frontage Standards. Except as expressly allowed in Sec. 17-2-0302-B, all lots in RS1 and RS2 districts must have a minimum lot frontage of 25 feet or the predominant lot frontage of similarly zoned lots on the same block face, whichever is greater. (See Sec. 17-17-0303 for rules governing the measurement of lot frontage.)
      17-2-0302-B Exemption. A detached house may be established on any lot of record regardless of its lot frontage, provided that all other requirements of this Zoning Ordinance are met. This exemption also applies if a lot of record is increased in area and still does not comply with applicable minimum lot frontage standards.
   17-2-0303 Lot Area per Unit (Density).
      17-2-0303-A Minimum Lot Area per Unit Standards. All development in R districts is subject to the following minimum lot-area-per-unit standards. These standards are not to be interpreted as a guarantee that allowed densities can be achieved on every lot. Other factors, such as off-street parking, height limits, dwelling unit sizes and lot configuration may work to limit density more than these standards.
 
District
Minimum Lot Area per Unit*
(square feet)
RS1
6,250
RS2
5,000
RS3
2,500, except as expressly allowed in Sec. 17-2-0303-B
RT3.5
1,250
RT4
Dwelling units: 1,000
Efficiency units: 1,000
SRO units: 500
RM4.5
Dwelling units: 700
Efficiency units: 700
SRO units: 500
RM5
Dwelling units: 400
Efficiency units: 400
SRO units: 200
RM5.5
Dwelling units: 400
Efficiency units: 400
SRO units: 200
RM6
Dwelling units: 300
Efficiency units: 135
SRO units: 135
RM6.5
Dwelling units: 300
Efficiency units: 135
SRO units: 135
 
(*See Sec. 17-17-0304 for rules governing the measurement of lot area per unit.)
      17-2-0303-B Exemption. In the RS3 district the minimum lot area per dwelling unit may be reduced to 1,500 square feet when 60% or more of the zoning lots fronting on the same side of the street between the two nearest intersecting streets have been lawfully improved with buildings containing more than one dwelling unit. This exemption will only allow for the establishment of a two unit building.
      17-2-0303-C Conversion Unit. Within Additional Dwelling Unit-Allowed Areas, in the case of building permit applications for the repair, remodeling, or alteration of residential buildings that are located in any RS2, RS3, RT or RM zoning district and that have been in lawful existence for 20 or more years, the density of such residential buildings may be increased in accordance with Section 17-9-0131 by 33% of the number of lawfully established dwelling units, other than conversion units, that have been in existence in the residential building for 20 or more years; provided, however, that if such residential building contains a single dwelling unit, the density of such residential building may be increased by one dwelling unit. If this 33% calculation results in a fractional number, any fractional result of 0.5 or more must be rounded up to the next consecutive whole number; and any fractional result of less than 0.5 must be rounded down to the previous consecutive whole number.
   17-2-0304 Floor Area Ratio.
      17-2-0304-A Standards. All development in R districts is subject to the following maximum floor area ratio standards:
 
District
Maximum Floor Area Ratio*
RS1
0.50
RS2
0.65
RS3
0.90
RT3.5
1.05
RT4
1.20 (See accessible dwelling unit exceptions, Sec. 17-2-0304-B)
RT4A
1.50 for multi-unit buildings that contain no more than 19 dwelling units and in which at least 33% of the units are accessible dwelling units 1.2 for all other buildings
RM4.5
1.70
RM5
2.00
RM5.5
2.50
RM6
4.40; premium may apply - See Sec. 17-2-0304-C
RM6.5
6.60; premium may apply - See Sec. 17-2-0304-C
 
(*See Sec. 17-17-0305 for rules governing the measurement of floor area ratio.)
      17-2-0304-B Exceptions.Multi-unit buildings in the RT4 district that contain no more than 19 dwelling units and in which at least 33% of the units are accessible dwelling units are subject to the maximum floor area ratio of the RT4A district if either of the following conditions exist:
         1.   more than 50% of the zoning lots fronting on the same side of the street between the two nearest intersecting streets contain buildings with a height of 38 feet or more; or
         2.   if the abutting lots on both sides of the subject lot contain buildings with a height of 38 feet or more.
      17-2-0304-C Premiums.Multi-unit residential buildings located in an RM6 or RM6.5 district on lots that permit 50 or more dwelling units, based on the lot's zoning classification, are eligible for floor area ratio premiums in accordance with the following: For each one percent decrease in the number of dwelling units below the maximum number permitted under Sec. 17-2-0303-A, a 0.50% increase in the allowable floor area ratio is allowed, provided that the floor area ratio is not increased by more than 25% over the otherwise applicable maximum under Sec. 17-2-0304-A.
      17-2-0304-D Exemption. Ground floor accessible dwelling units are exempt from inclusion in floor area ratio calculations, that is, the square footage of a ground floor accessible dwelling unit shall not be included in calculating that building's total floor area ratio in R53, R53.5. RT4 [except single-family residences] zoning districts. Proponents will certify under oath that grade level units will be built for parties with disabilities for perpetual use.
   17-2-0305 Front setbacks.
      17-2-0305-ABuildings and structures in RS districts must be set back from the front property line a distance equal to the average front yard depth that exists on the nearest 2 lots on either side of the subject lot, excluding the lot with the least front yard depth. In those cases when the least front yard depth is identical for 2 or more lots, only a single lot shall be excluded from the calculation.
      17-2-0305-BBuildings and structures in RT, RM and DR districts must be set back from the front property line a distance equal to either: the minimum front setback standard of 15 feet (or 12% of lot depth, whichever is less) or the average front yard depth that exists on the nearest 2 lots on either side of the subject lot. In RT, RM and DR districts the decision to comply with the fixed front setback standard or the average front setback standard is left to the builder / property owner except in the case of lots with lot frontage on a primary boulevard, as defined in Sec. 17-17-02124, where buildings and structures must be set back from the front property line a distance equal to the average front yard depth that exists on the nearest 2 lots on both sides of the subject lot; there is no maximum depth to the required setback along a primary boulevard as defined in Sec. 17-17-02124. (See Sec. 17-17-0306 for rules governing the measurement of front setbacks)
      17-2-0305-C If one or more of the lots required to be included in the averaging calculation are vacant, such vacant lots will be deemed to have the following front yard depths:
 
District
Assumed Setback on Vacant Lots
RS1 to RS3
20 feet or 16% of lot depth, whichever is less
RT3.5 to RM6.5 + DR
15 feet or 12% of lot depth, whichever is less
 
Figure 17-2-0305-C
 
         1.   Lots that front on a different street than the subject lot or that are separated from the subject lot by a street or alley may not be used in computing the average.
Figure 17-2-0305-C1
 
         2.   When the subject lot is a corner lot, the average setback will be computed on the basis of the nearest 2 lots that front on the same street as the subject lot.
         3.   When the subject lot abuts a corner lot fronting on the same street, the average setback will be computed on the basis of the abutting corner lot and the nearest 2 lots that front on the same street as the subject lot.
      17-2-0305-D The setback provisions of this section (Sec. 17-2-0305) do not apply to townhouses. Townhouses are subject to the standards of Sec. 17-2-0500.
      17-2-0305-E If the averaged front yard is 50% or less then the fixed front yard setback, then the features allowed to encroach in required setbacks established in Sec 17-17-0309 do not apply.
   17-2-0306 Rear Setbacks.
      17-2-0306-A In all R districts, the minimum rear setback for buildings that contain no more than 19 dwelling units and in which at least 33% of the units are accessible dwelling units is 24% of lot depth or 50 feet, whichever is less. (See Sec. 17-17-0307 for rules governing the measurement of rear setbacks.)
      17-2-0306-B In all R districts, the minimum rear setback for detached houses is 28% of lot depth or 50 feet, whichever is less. (See Sec. 17-17-0307 for rules governing the measurement of rear setbacks.)
      17-2-0306-C In all R districts, the minimum rear setback for principal buildings other than detached houses is 30% of lot depth or 50 feet, whichever is less.
      17-2-0306-D In RM5 and RM 5.5 districts, the required rear setback applies to all portions of the building that are 6 feet or more above grade.
      17-2-0306-E In RM6 and RM6.5 districts, the required rear setback applies to all portions of the building that are 18 feet or more above grade.
      17-2-0306-F In all R districts other than RM5, RM5.5, RM6 and RM6.5, the required rear setback applies to all portions of the building.
   17-2-0307 Rear Yard Open Space. All development in RS, RT, RM4.5 and RM5 districts is subject to the following minimum rear yard open space standards, except as expressly allowed under the townhouse development standards of Sec. 17-2-0500.
 
District
Minimum Rear Yard Open Space
(square feet per dwelling unit/% of lot area, whichever is greater)
Minimum Dimension
on Any Side (feet)
RS1
400/6.5
20
RS2
400/6.5
20
RS3
225/6.5
15
RT3.5
100/6.5
12
RT4
65/6.5
12
RT4A
65/6.5
12
RM4.5
50/6.5
10
RM5
36/5.25
10
 
      17-2-0307-A Location and Design.
         1.   Rear yard open space refers to the amount of lot area required to be preserved as open space within the rear yard.
         2.   Required rear yard open space must be located within the rear yard, at ground level or, if located on a terrace or patio, within 4 feet of ground level. In RM5 and RM5.5 districts, where structures are located in the rear setback and do not exceed 6 feet in height, required rear yard open space may be located directly above such structures.
         3.   When located at ground level, the open space area must be substantially covered with grass, ground cover, shrubs, plants, trees, or usable outdoor open space features, such as walkways or patios.
         4.   Off-street parking areas and driveways may not be used to satisfy rear yard open space requirements. Bollards, curbs, wheel stops or other similar features must be provided to ensure that required rear yard open space is not used for off-street parking, loading or vehicle circulation.
         5.   If a rear setback is reduced by a variation or administrative adjustment, the rear yard open space must either be located in the rear setback, or between the established rear setback or accessory building and any principal building. The required open space may also be provided on the roof of an accessory building as allowed in Sec. 17-13-1003-K and Sec. 17-13-1101-A.
   17-2-0308 On-Site Open Space in RM5.5, RM6 and RM6.5 Districts.
      17-2-0308-A Amount and Dimensions. Except as expressly allowed under the townhouse development standards of Sec. 17-2-0500, all development containing dwelling units located in RM5.5, RM6 and RM6.5 districts must provide at least 36 square feet of useable on-site open space per dwelling unit. Required open space must have minimum dimension of at least 5 feet on any side if private or 15 feet on any side if provided as common open space.
      17-2-0308-B Additional Standards.
         1.   Required open space must be located on the same lot as the dwelling unit it serves.
         2.   Required open space must be outdoors and designed for outdoor living, recreation or landscaping, including areas located on the ground and areas on decks, balconies, porches or roofs.
         3.   The required open space area is not required to be contiguous, but each open space area, whether common or private, must comply with minimum dimensional standards. Common open space areas must be accessible to all residents of the subject development.
         4.   When located at ground level, required open space area must be substantially covered with grass, ground cover, shrubs, plants, trees, or usable outdoor open space features, such as walkways or patios.
         5.   Off-street parking areas, loading facilities, driveways or required vehicular use landscape areas may not be used to satisfy open space requirements. Bollards, curbs, wheel stops or other similar features must be provided to ensure that required open space areas are not used for off-street parking or any other vehicular use.
         6.   Required open space areas may not be occupied by mechanical equipment, dumpsters or service areas.
         7.   All required open space areas must be located and designed to take advantage of sunlight and other climatic advantages of the site.
   17-2-0309 Side Setbacks.
      17-2-0309-A Standards. All development in R districts is subject to the following minimum side setback standards, except as expressly allowed under the townhouse development standards of Sec. 17-2-0500. Reversed corner lots are subject to Sec. 17-2-0309-B. (See Sec. 17-17-0308 for rules governing the measurement of side setbacks.)
 
District
Minimum Side Setback
RS1
Detached house: Combined total width of side setbacks must equal 30% of lot width with neither required setback less than 5 feet or 10% of lot width, whichever is greater
Principal nonresidential building (e.g., religious assembly and school buildings): 15 feet or 50% of building height, whichever is greater
RS2
Detached house: Combined total width of side setbacks must equal 30% of lot width with neither required setback less than 4 feet or 10% of lot width, whichever is greater
Principal nonresidential building (e.g., religious assembly and school buildings): 15 feet or 50% of building height, whichever is greater
RS3
Detached houses: Combined total width of side setbacks must equal 20% of lot width with neither required setback less than 2 feet or 8% of lot width, whichever is greater
Principal nonresidential buildings (e.g., religious assembly and school buildings): 12 feet or 50% of building height, whichever is greater
RT3.5
Townhouse: See Sec. 17-2-0500
All other principal buildings: Combined total width of side setbacks must equal 20% of lot width with neither required setback less than 2 feet or 8% of lot width, whichever is greater; no side setback is required to exceed 5 feet in width; See also note 1, below
RT4/RT4A
Townhouse: See Sec. 17-2-0500
All other principal buildings: Combined total width of side setbacks must equal 20% of lot width with neither required setback less than 2 feet or 8% of lot width, whichever is greater; no side setback is required to exceed 5 feet in width; See also note 1, below
RM4.5
Townhouse: See Sec. 17-2-0500
All other principal buildings: Combined total width of side setbacks must equal 20% of lot width with neither required setback less than 2 feet or 8% of lot width, whichever is greater; no side setback is required to exceed 5 feet in width; See also note 1, below
RM5
Townhouse: See Sec. 17-2-0500
All other principal buildings: Combined total width of side setbacks must equal 20% of lot width with neither required setback less than 2 feet or 8% of lot width, whichever is greater; no side setback is required to exceed 5 feet in width; See also note 1, below
RM5.5
Townhouse: See Sec. 17-2-0500
All other principal buildings: Combined total width of side setbacks must equal 20% of lot width with neither required setback less than 2 feet or 8% of lot width, whichever is greater; no side setback is required to exceed 5 feet in width; See also note 1, below
RM6
Townhouse: See Sec. 17-2-0500
All other principal buildings: None abutting street or alley or for buildings covering 50% or less of the lot; buildings covering more than 50% of the lot must provide individual side setbacks equal to at least 10% of the lot width or 10% of the total building height, whichever is greater, provided that no side setback is required to exceed 20 feet in width
RM6.5
Townhouse: See Sec. 17-2-0500
All other principal buildings: None abutting street or alley or for buildings covering 50% or less of the lot; buildings covering more than 50% of the lot must provide individual side setbacks equal to at least 10% of the lot width or 10% of the total building height, whichever is greater, provided that no side setback is required to exceed 20 feet in width
 
[1] When a side lot line abuts an alley or street, no side setback is required on the side of the building abutting the street or alley. In such cases, the side setback on the other (non-street or alley) side must be at least 10% of the lot's width.
      17-2-0309-B Reversed Corner Lot Setback Standards. In all R districts, the minimum side setback on a reversed corner lot must be equal to at least 50% of the front yard that exists on the lot abutting the rear of the reversed corner lot. If the abutting lot to the rear is vacant, the 50% is to be calculated on the basis of the abutting lot's required front setback. Moreover, no accessory building on a reverse corner lot may be located within 5 feet of a rear lot line that abuts a side lot line of an RS1-, RS2-, or RS3-zoned lot.
Figure 17-2-0309-B
      17-2-0309-C Through Lots. On through lots both (opposing) street lines are considered front property lines and front setback standards apply. Rear setback standards do not apply. On through lots that are at least 125 feet in depth one of the following must be provided on each floor of the building containing residential dwelling units:
         1.   unobstructed open space located midway between the streets on which such lot fronts and running the full width of the lot. This required open space must provide at least 10 feet of separation between buildings or segments of buildings located on the zoning lot, plus an additional 2 feet of separation for every 5 feet or fraction thereof by which the lot depth exceeds 125 feet. In RM5, RM5.5, RM6 and RM 6.5 districts, the required open area may begin the same distance above grade as the required rear setback. Regardless of lot depth, this open area need not provide more than 60 feet of building separation; or
         2.   unobstructed open space along all property lines other than streetproperty lines. This open space must be at least 5 feet in width, plus an additional one foot for every 5 feet or fraction thereof by which the lot depth exceeds 125 feet. Regardless of lot depth, this open space need not exceed 30 feet in width.
Figure 17-2-0309-C
   17-2-0310 Building (Wall) Separation.
      17-2-0310-A Purpose; Applicability. The building separation standards of this section are intended to ensure adequate separation between exterior building walls that serve as a primary source of natural light and air for dwelling units. These standards apply to courtyard buildings, buildings with car courts, or other developments where dwelling units face or are adjacent to one another. Townhouse developments are exempt from these standards; they are subject to the standards of Sec. 17-2-0500.
      17-2-0310-B General. Unless otherwise expressly stated, exterior building walls are subject to the minimum setback standards of the underlying zoning district.
      17-2-0310-C Front and Rear Walls.
         1.   Facing Interior Side Property Line.
            (a)   When a front wall faces the subject property's interior side property line, the front wall must be setback from the interior side property line a distance equal to at least 12 feet. (See Sec. 17-17-0310 for rules governing the measurement of building wall separation.)
            (b)   When a rear wall faces the subject property's interior side property line, the rear wall, must be setback from the interior side property line a distance equal to at least 10% of the lot width or 12 feet, whichever is less.
Figure 17-2-0310-C1
         2.   Facing Other Front or Rear Walls. When the front wall or rear wall of a dwelling unit faces the front wall or rear wall of another dwelling unit located on the same zoning lot, the minimum required separation between such walls (excluding minor building projections allowed under Sec. 17-2-0500-H4) is as follows:
 
District
Minimum Separation
(feet)
RT3.5
30
RT4
30
RM4.5
30
All other R districts
26
 
Figure 17-2-0310-C2
      17-2-0310-D End Walls Facing Front or Rear Walls. When the end wall of a dwelling unit faces the front wall or rear wall of a dwelling unit located on the same zoning lot, the minimum required separation between such walls is 20 feet. Balconies and minor building projections allowed under Sec. 17-2-0500-H4 are allowed to encroach into required separation areas.
Figure 17-2-0310-D
   17-2-0311 Building Height.
      17-2-0311-A Standards. All residential buildings in R districts are subject to the following maximum building height standards except as expressly allowed in Sec. 17-2-0311-B:
 
District
Maximum Building Height (feet)
RS1
Detached house: 30
Principal nonresidential buildings: None
RS2
Detached house: 30
Principal nonresidential buildings: None
RS3
Detached house: 30
Principal nonresidential buildings: None
RT3.5
Principal residential buildings: 35
Principal nonresidential buildings: None
RT4
Principal residential buildings: 38
Principal nonresidential buildings: None
RT4A
Multi-unit buildings that contain no more than 19 dwelling units and in which at least 33% of the units are accessible dwelling units: 42
All other principal residential buildings: 38
RM4.5
Principal residential buildings:
Lot Frontage of less than 32 feet: 45
Lot Frontage of 32 feet or more: 47
Principal nonresidential buildings: None
RM5
Principal residential buildings:
Lot Frontage of less than 32 feet: 45
Lot Frontage of 32 feet or more: 47
Principal nonresidential buildings: None
RM5.5
Principal residential buildings:
Lot Frontage of 75 feet or less: 47
Lot Frontage of more than 75 feet: 60
Principal nonresidential buildings: None
RM6
Principal residential buildings: None (tall buildings require Planned Development approval in accordance with Sec. 17-13-0600)
Principal nonresidential buildings: None
RM6.5
Principal residential buildings: None (note: tall buildings require Planned Development approval in accordance with Sec. 17-13-0600)
Principal nonresidential buildings: None
 
(See Sec. 17-17-0311 for rules governing the measurement of building height.)
      17-2-0311-A[a] Exceptions.Multi-unit buildings in the RT4 district that contain no more than 19 dwelling units and in which at least 33% of the units are accessible dwelling units are subject to the maximum building height standard of the RT4A district if either of the following conditions exist:
         1.   more than 50% of the zoning lots fronting on the same side of the street between the two nearest intersecting streets contain buildings with a height of 38 feet or more; or
         2.   if the abutting lots on both sides of the subject lot contain buildings with a height of 38 feet or more.
      17-2-0311-B Exemption. The building height limits of Sec. 17-2-0311-A do not apply to residential construction in the “Wrigley Field Adjacent Area”, as defined in Chapter 4-388 of the Municipal Code.
   17-2-0312 Average Dwelling Unit Size. The gross residential floor area developed on a lot divided by the total number of dwelling units on such lot may not be less than 500 square feet. Existing residential uses may not be converted to conflict with or further conflict with this standard. The average dwelling unit size standard of this section does not apply to government-subsidized or elderly housing developments.
   17-2-0313 Number of Efficiency Units.
      17-2-0313-A Standards. In those R districts in which efficiency units are allowed, the total number of efficiency units may not exceed the following standards except as expressly allowed in Sec. 17-2-0313-B:
 
District
Maximum Number of Efficiency Units (% of total units)
RT4
20
RM4.5
20
RM5
20
RM5.5
25
RM6
30
RM6.5
40
 
      17-2-0313-B Exemption.The limits on efficiency units do not apply to SROs, government- subsidized or elderly housing developments, provided that the Zoning Administrator determines that such developments constitute bona fide SROs, government- subsidized or elderly housing developments.
(Added Coun. J. 5-26-04, p. 25275; Amend Coun. J. 3-9-05, p. 44391; Amend Coun. J. 11-30-05, p. 62716; Amend Coun. J. 9-13-06, p. 84870, §§ 2, 3; Amend Coun. J. 11-5-08, p. 45002, § 1; Amend Coun. J. 4-15-15, p. 106130, § 14; Amend Coun. J. 12-16-20, p. 26066, § 11; Amend Coun. J. 3-24-21, p. 29065, § 1)

 

Notes

4-388
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