A. 
Any accessory use or structure shall conform to the applicable regulations of the district in which it is located except as specifically otherwise provided.
B. 
No accessory use or structure shall be permitted that by reason of noise, dust, odor, appearance, or other objectionable factor creates a nuisance or substantial adverse effect on the property value or reasonable enjoyment of the surrounding properties.
C. 
No accessory use or structure shall be permitted without a principal use on a property except as specifically otherwise provided.
D. 
In any case where the principal use is permitted as a conditional grant, or is permitted only after approval of building, site and operation plans, the requirements of Subsections A and B above shall apply also to any use or structure accessory thereto, except that where such accessory use is added subsequent to the original approval, the Plan Commission may grant approval of any such accessory use without necessity for public hearing if in its opinion it is compatible with the original grant and is not of sufficient scope or different character to necessitate further public hearings.
A. 
When permitted. Home occupations shall be permitted as an accessory use when incident to the principal residential use, situated in the same building, and carried on by the residential occupant, subject to the provisions of this section.
B. 
Business registration required. The Public Works and Development Director or his designee may approve home occupations without necessity of a building, site and operation plan. All persons engaged in home occupations shall register their use by completing a business registration form available through the Public Works and Development Department. Updates to an approved home occupation may be requested at any time by the Public Works and Development Director or designee as need be or revocation of an approved home occupation may result.
C. 
Regulations applicable to home occupations:
(1) 
Such use shall not occupy more than 20% of the assessed floor area of the principal structure in which it is located.
(2) 
Such use shall not employ more than one person not a resident on the premises.
(3) 
No such use shall be permitted which normally necessitates the coming of the customer or client to the premises, or his presence on the premises while the service is being performed, or otherwise generates pedestrian or vehicular traffic incompatible with the rural or residential character of the neighborhood, except for teaching or tutoring academic subjects, or the studios where dancing, music or other art instruction is offered to no more than two pupils at one time.
(4) 
Any off-street parking area provided shall be maintained reasonably dustless and adequately screened from adjoining residential properties.
(5) 
Such use shall not include the conduct of any retail or wholesale business on the premises, nor the removal of sand, gravel, stone, topsoil, or peat moss for commercial purposes.
(6) 
Such use shall not include the operation of any machinery, tools or other appliances, or the outside storage of materials, or other operational activity which would create a nuisance or be otherwise incompatible with the surrounding residential area.
(7) 
A nameplate not in excess of two square feet in area shall be permitted.[1]
[1]
Editor's Note: Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. II).
(8) 
Home occupations are first and foremost for home office type uses in the principal structure. Any outdoor needs of a home occupation will be highly scrutinized and may require Plan Commission approval so as to regulate exactly what the outdoor activities and uses consist of.
(9) 
A home occupation use is allowed in residentially zoned areas. However, the areas are first and foremost for residentially oriented uses. Residents in a neighborhood should not notice that a business is being operated from this property. Home occupation uses that are deemed a nuisance to surrounding neighbors must be corrected or may be revoked.
(10) 
Home occupation uses must follow all adopted commercial vehicle/trailer regulations as listed in § 400-190L. No exceptions to these requirements are allowed as part of an approved home occupation.
[Added 2-4-2010 by Ord. No. 1311]
A. 
When permitted. Mother-in-law units as defined in this code shall be permitted as an accessory use when incident to the principal residential use, situated in the same building, and carried on by the residential occupant, subject to the provisions of this section.
B. 
Building, site and operation plan required. All proposed mother-in-law units are subject to building, site and operation plan approval by the Plan Commission following written notice being distributed by the City to neighboring property owners within 100 feet of the subject property.
C. 
Regulations applicable to mother-in-law units. Such units may be occupied by a resident(s) related through blood, marriage or adoption to a host residence occupant.
(1) 
Such units shall be no larger than 800 square feet in net floor area.
(2) 
Access to the unit must be obtained via one door to the outside and a second nonlockable door or passageway to the main portion of the host residence. Access is permitted to a garage area having no service door.
(3) 
Such units shall be dependent on utility infrastructure of the primary residence (i.e., sharing a common water meter, electric panel, etc.).
(4) 
Such units shall be self-supporting in terms of livable needs (i.e., unit includes a kitchen, bath, den and bedroom).
[Amended 6-26-2018 by Ord. No. 1418; 3-18-2020 by Ord. No. 1442]
A. 
When permitted. Hobby kennels, as defined in this code, shall be permitted as an accessory use on any property zoned for residential use, where said kennel is incidental to the principal residential use, subject to the provisions of this section.
B. 
Building, site and operation plan required. All proposed hobby kennels are subject to building, site and operation plan approval by the Plan Commission following written notice being distributed by the City to neighboring property owners within 100 feet of the subject property.
C. 
Regulations applicable to hobby kennels. On properties in the RCE Zoning District, or on properties totaling a minimum of 120,000 square feet, one additional dog per acre, above the number of dogs permitted per household per Chapter 140, Animals, of the City Code, may be permitted upon written notice being given by the Plan Commission to property owners within 100 feet of the property in question, and subject to building, site and operation plan approval by the Plan Commission per § 400-21 of this chapter.
A. 
General. Accessory structures shall reflect or compliment the character or materials of the primary structure.[1]
[1]
Editor's Note: Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. II).
B. 
Attached accessory structures. In all districts, any permanent roofed structure serving an accessory use if attached to the principal building shall be considered as part of such principal building for all regulatory purposes. If such structure is a building and is not attached to the principal building it shall conform to the building location, height, and open space requirements of the district in which such building is located.
C. 
Detached accessory structures in residential districts. Detached accessory structures located on parcels in a residence district where the principal use is present, except boathouses, shall be permitted subject to the following:
(1) 
Location. All accessory structures subject to this section shall be located behind the base setback line of all street yards and behind the minimum required offsets of all other side/rear lot lines.[2]
[2]
Editor's Note: Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. II).
(2) 
Area. Subject to the open space requirements of the zoning district, the total square footage of all accessory structures subject to this section is permitted as follows:
(a) 
Square footage permitted by right: the greater of 720 square feet or 60% of the assessed floor area of the principal structure.
(b) 
Bonus square footage permitted for additional side yard offsets: plus 10 square feet of floor area for each one foot of side yard offset above the district minimum, provided that no such bonus shall exceed 300 square feet.
(c) 
Square footage permitted for large parcels: parcel sizes in excess of 40,000 square feet are allowed a maximum total floor area of all accessory structures not to exceed 2% of the total parcel area.
(3) 
Height. The height of all accessory structures subject to this section shall conform to the following:
(a) 
Private garden sheds.
Minimum Side Yard Offset
(feet)
Permitted Height Above Grade
(feet)
3
9
5
13
10
15
(b) 
Private garages and other accessory structures.
[1] 
Height permitted by right: 15 feet.
[2] 
Height bonus permitted for additional offset: plus one foot of height for every five feet of setback above the district minimum, provided that no such bonus shall result in a structure exceeding 20 feet in height as measured by § 400-24.
[3] 
Height bonus permitted for large parcels: plus one foot of height for every 10,000 square feet of parcel in excess of 40,000 square feet, provided that no such bonus shall result in an accessory structure which exceeds the height permitted for principal structures in the zoning district.
(4) 
Number. No more than one accessory structure in excess of 120 square feet shall be permitted on a lot except when the Plan Commission finds that multiple accessory structures would meet the requirements set forth in Subsection C(2) above. One private garden shed (an accessory structure 120 square feet or less) is permitted on a residential lot and Plan Commission approval is needed when two structures of this nature are sought. An individual may have a private garden shed and an accessory structure greater than 120 square feet without Plan Commission approval.
(5) 
Architectural requirements. All accessory structures subject to this section must conform to the following additional requirements:
(a) 
A minimum base floor consisting of either pressure-treated lumber, asphalt flooring, sealed concrete block, or concrete slab must be provided, except such areas where domesticated animals and livestock are to be quartered as permitted by this chapter.
(b) 
The architectural materials, color, and style of accessory structures shall conform to the materials, color, and style of the principal structure unless the property is subject to a design guide duly adopted as a component of the Comprehensive Plan and the proposed accessory structure is in conformance with the provisions of said guide. Exceptions to this requirement may be made by the Plan Commission where it is determined that the structure meets one or more of the following:
[1] 
The structure is screened from view.
[2] 
The principal structure is composed of materials, colors, or styles that are inappropriate in their application to an accessory structure.
[3] 
The Plan Commission finds other circumstances to be present which would result in undue harm to the property or its surroundings.
(6) 
Use restricted. No private garage in a residence district shall be used for operation of any metalworking, woodworking, masonry, carpentry, contracting, or repair business except as a permitted accessory use or home occupation.
(7) 
Rustic structures as defined in this code shall be allowed as a conditional use upon approval of the Plan Commission. If granted conditional use status, the rustic structure is not required to comply with the location, area, height, and architectural requirements for detached accessory structures in the district.
D. 
Boathouses. Properties within the RL-1, RL-2 and RL-3 Lakeshore Residence Districts are permitted one boathouse subject to the following:
(1) 
Location: minimum 20 feet from the ordinary high-water mark and subject to the side yard offset provisions of the district, effective with new construction or relocations after November 15, 2001.
(2) 
Height: not greater than 15 feet above the lowest grade.
(3) 
Area: no greater than 525 square feet.
(4) 
The boathouse must be designed and used principally for the storage of boats and accessory marine equipment normally used in the daily activities of lakefront property and typically includes a large overhead door for primary access on the side of the structure facing the water.
(5) 
A boathouse may not be habitable as defined in this code. Final decision as to whether any boathouse would be considered habitable will be determined by the Public Works and Development Department.[3]
[3]
Editor's Note: Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. II).
E. 
Detached accessory structures; agricultural districts and uses.
(1) 
Detached accessory structures located on parcels in the A-1 Agricultural District, where said parcels are equal or greater than 120,000 square feet in area, are subject to the regulations of the district pursuant to Article VIII.
(2) 
Detached accessory structures located on parcels in the A-1 Agricultural District which are located on parcels less than 120,000 square feet in area and where the principal use is present shall be subject to the provisions of this section above.
(3) 
An accessory structure with an agriculture use located within any zoning district other than the A-1 Agricultural Zoning District must follow the architectural requirements found in Subsection C(5), unless Plan Commission approvals are sought to allow decreased architectural requirements.
(4) 
All agricultural accessory structures shall follow the permitting and architectural standards shown in the City of Muskego adopted General Design Guide.
(5) 
Rustic structures as defined in this code shall be allowed as a conditional use in the A-1 Agricultural District. As authorized by conditional use grant, rustic structures are exempt from the requirements of this section.
F. 
Detached accessory structures in business and industrial districts. Detached accessory structures located on parcels in any business or industrial zoning district where the principal use is present shall conform to the bulk requirements of the zoning district.
G. 
Outdoor lighting. Outdoor lighting installations for residential uses shall be permitted in the setback and offset areas but not closer than three feet to an abutting property line and, where not specifically otherwise regulated, shall not exceed 15 feet in height and shall be adequately shielded or hooded so that no excessive glare or illumination is cast upon the adjoining properties. Outdoor lighting installations for commercial/industrial uses shall comply with the provisions of Article XVIII of this code for those installations associated with a building, site and operation plan.
H. 
Fences and walls. Fences and walls, where anchored to supports embedded in the ground, shall be considered permanent structures and shall be subject to the following:
[Amended 2-4-2010 by Ord. No. 1311; 8-19-2010 by Ord. No. 1326]
(1) 
Fences are allowed anywhere on a single property, with a proper zoning permit, as long as the fencing remains completely on the property. Fence panels are allowed to be up to six feet in height, with up to an additional six inches being allowed for ground clearance and post/cap height. The total height of any installed fencing system (fence panels, posts, and caps) cannot exceed a maximum combined height of six feet six inches. The total fence system heights are measured from the natural grade at any point along the base of the fence/posts to the top of the highest fence panel, post, or post cap.
[Amended 3-22-2012 by Ord. No. 1351[4]]
[4]
Editor's Note: Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. II).
(2) 
Any such fence in excess of the height listed in Subsection H(1) may be permitted provided it conforms to the height, offset, and setback requirements of the district in which it is located.
[Amended 3-22-2012 by Ord. No. 1351]
(3) 
If the fence or wall is going to be located on a berm, the berm cannot have slopes that measure steeper than a slope of four feet horizontal to one foot vertical. Also, the top of the berm must have a level area on each side of the fence or wall that is at least two feet wide. These requirements apply to any new/replacement fencing or wall on an existing or proposed berm.
[Amended 3-22-2012 by Ord. No. 1351]
(4) 
The decorative side of all fencing must face the neighboring properties.
(5) 
All fencing in residential districts must be constructed out of materials that are traditionally found in residential areas.
(6) 
Retaining walls or decorative walls may be permitted anywhere on the lot; provided, however, that no individual wall shall exceed six feet in height. When multiple walls are being installed, a terrace equal to half of the tallest wall height must be provided between each of the multiple walls.
[Amended 4-18-2013 by Ord. No. 1371]
I. 
Walks, drives, paved terraces, mechanical appurtenances for all single-family and two-family structures (such as air conditioners, venting, and service panels), and purely decorative garden accessories (such as pools, fountains, statuary, flagpoles, etc.), where subject to "permanent structure" classification, shall be permitted in setback and offset areas but not closer than three feet to an abutting property line other than a street line.
J. 
Game courts shall be permitted in setback and offset areas but not closer than five feet to any property line and shall be screened from the view of adjoining property by adequate landscape or architectural screen or combination thereof.
K. 
Parking areas shall be permitted in setback and offset areas but not closer than three feet to any property line and said areas shall be temporary in nature.
L. 
Solar collectors shall be permitted as an accessory use and may be permitted in any district subject to the regulations of the particular district.
M. 
Temporary structures and miscellaneous screening devices. Any temporary structure or miscellaneous screening device serving an accessory use shall be permitted anywhere on the lot consistent with the standards as set out in Subsection C above and no building permit shall be required provided a zoning permit is obtained. However, where such proposed structure does not comply with the setback and offset requirements of the district in which it is located or where such proposed structure does not comply with architectural standards, the approval of the Plan Commission must first be obtained. Plan Commission approval for such modification in setback/offset or architectural requirements shall be based on the following:
[Amended 2-4-2010 by Ord. No. 1311]
(1) 
The proposed structure is out of public view or adequately screened.
(2) 
Notice of meeting is given to owners within 100 feet of property lines.
(3) 
If the miscellaneous screening device is a carport, it shall have no sides or ends.
(4) 
May be subject to annual review by the Plan Commission for yearly maintenance concerns.
N. 
Outdoor storage. No unenclosed storage of materials, equipment, temporary structure, supplies or vehicles shall be permitted where such storage is unsightly to the surrounding view.
A. 
Structures less than six inches in height. Structures not classified as buildings and less than six inches in height from the surface of the ground shall not be subject to the setback, offset, building size, or open space requirements of this chapter except as may be specifically otherwise provided.
B. 
Structures six inches or more in height. Structures not classified as buildings and six inches or more in height from the surface of the ground shall be subject to the setback, offset, height, open space, and architectural requirements of this chapter except as may be specifically otherwise provided.
Any structure classified as a building and not extending more than six inches above the surface of the ground shall not be subject to the setback, offset, building size, or open space requirements of this chapter.
Roadside stands for seasonal agricultural sales of products raised on the premises and operated by the resident farmer are permitted in any district subject to the following:
A. 
In all districts except the A-1 Agricultural District, Plan Commission approval of a building, site and operation plan is required.
B. 
No roadside operation shall exceed 300 square feet in area, exclusive of parking required herein.
C. 
Where roadside stands have ingress and egress on roadways under Waukesha County jurisdiction, approval of the Waukesha County Department of Transportation is required.
D. 
Off-street parking for a minimum of four vehicles shall be provided.
E. 
No stand shall be permitted in a location where it would create a traffic hazard or nuisance, and, where permitted, driveways shall be so located as to minimize possible interference with normal flow of highway traffic.
F. 
No such stand shall be closer than 30 feet to the existing street line or closer than 20 feet to any other lot line.
G. 
Signs shall conform to the requirements of Article XVI of this chapter.
In any district, space not to exceed 300 square feet for the storage of not more than one vehicle may be rented to persons not resident on a parcel. A maximum of two rental spaces not to exceed 600 square feet may be permitted where they are the only parking spaces provided on said lot, subject to the following:
A. 
Parking storage areas must be located outside setback and offset areas of the property.
B. 
Parking stalls must follow the requirements found in Article XVII of this chapter.
A. 
Household and farm related. Second accessory residences for household or farm employees are permitted by conditional use grant, provided that such quarters shall be occupied only by individuals employed full time on the premises and their families and/or by persons related to the residents of the principal structure. Such structures shall be a minimum of 1,200 square feet and shall not be rented or leased.
B. 
Guesthouses. Guesthouses are permitted by conditional use grant on lots of at least 120,000 square feet. Such structures shall be a minimum of 1,200 square feet and shall not be rented or leased.