377 / 634
Article 3 Zoning Districts
3-74 WSO, Water Supply Watershed Overlay District
Wake County Unified Development Code
3-57
Overlay District
Minimum Lot Area (sq. ft.)
Maximum Density (lots/acre)
Max. Impervious Surface
WSO-2NC [1]
40,000
1
12%
WSO-3CA [1]
40,000
1
12%
WSO-3NC [2]
20,000
2
24%
[1] In WSO-2NC and WSO-3CA districts, residential lots of at least 40,000 square feet in area and residential lots in a cluster
subdivision, open space subdivision or existing Consolidated Open Space Development with an overall lot density no more than
one lot per acre are not subject to impervious surface coverage limits except as required by the underlying zoning. For all other
residential lots and for nonresidential developments in those districts, impervious surface coverage may not exceed 12% of the
total area of the site, as designated on the site plan.
[2] In WSO-3NC districts, residential lots of at least 20,000 square feet in area and residential lots in a cluster subdivision, open
space subdivision or existing Consolidated Open Space Development with an overall lot density of no more than 2 lots per acre
are not subject to impervious surface coverage limits except as required by the underlying zoning. For all other residential lots
and for nonresidential developments in those districts, impervious surface coverage may not exceed 24 percent of the total area
of the site, as designated on the site plan.
(C) WSO-4P Districts
Development within WSO-4P districts must comply with the following standards
whenever they are more restrictive than those of the underlying zoning district.
(1) With Curb and Gutter
In a development served by a curb and gutter system, residential lots of at least
20,000 square feet in area and residential lots in a cluster subdivision, open space
development or existing consolidated open space development with an overall lot
density no more than 2 lots per acre, are not subject to impervious surface coverage
limits except as required by the underlying zoning. For all other residential lots and
for nonresidential developments, the following standards apply:
(a) WSO-4P1
In the WSO-4P1 district, impervious surface coverage may not exceed 24
percent of the total area of the site, as designated on the site plan.
(b) WSO-4P2
In the WSO-4P2 district, impervious surface coverage may not exceed 30
percent of the total area of the site, as designated on the site plan.
Commentary: Curb and gutter are limited in water supply watersheds. See Sec. 8-32-18.
(2) Without Curb and Gutter
In a development not served by a curb and gutter system, residential lots of at least
15,000 square feet in area and residential lots in a cluster subdivision, open space
development or existing consolidated open space development with an overall lot
density no more than 2 lots per acre, are not subject to impervious surface coverage
limits except as required by the underlying zoning. For all other residential lots and
for nonresidential developments, impervious surface coverage may not exceed 30
percent of the total area of the site, as designated on the site plan.
(3) Engineered Stormwater Control Structures
Engineered stormwater control structures must meet design guidelines of the State
Division of Water Quality, or its successor agency. Responsibility for maintenance of
all permanent infiltration, retention, and detention control measures and facilities,
after site development is completed, rests with the owner of the use. When designed
in accord with the guidelines of the State Division of Water Quality, or its successor