In addition to historic districts and individual historic landmarks, the Office of Historic Preservation (OHP) has review authority over additional zoning overlays, including the River Improvement Overlay (RIO) districts and viewshed districts. These zoning layers are authorized by the City's Unified Development Code (UDC) and place standards for urban design and development.
River Improvement Overlay (RIO) Districts
RIO is a zoning overlay. Its purpose is to establish regulations to protect, preserve and enhance the San Antonio River and its improvements by establishing design standards and guidelines for properties located near the river.
The San Antonio River is a unique and precious natural, cultural and historic resource that provides a physical connection through San Antonio by linking a variety of neighborhoods, cultural sites, public parks and destinations. The districts cover a total of seven geographic areas spanning the river from its northern boundary, near Hildebrand Avenue, to a southern boundary near Mission Espada and the southern city limits.
The RIO design objectives were developed through an intensive public input process and were adopted as part of the enabling ordinance approved by City Council on February 21, 2002.
Use the interactive map to explore RIO districts and boundaries.
RIO Districts Map
RIO Guidelines
In reviewing an application for a certificate of appropriateness for properties in the RIO districts, the Historic and Design Review Commission (HDRC) and the OHP consider the character and design objectives for each RIO district, as well as the design standards set forth in the UDC. There are also specific design standards for the River Walk specified in the UDC.
For criteria for approval (a Certificate of Appropriateness) in RIO districts, please refer to the UDC Section 35-670 or contact OHP staff for assistance.
RIO-1
Extending from Hildebrand Avenue south to US Highway 281 North, the northernmost of the RIO districts includes a mix of residential, commercial and recreational uses.
RIO-2
Extending south from US Highway 281 North to Lexington in the northern portion of downtown San Antonio, the area encompassed by RIO-2 includes small single-family residential pockets surrounded by a variety of higher-density and commercial uses.
RIO-3
Extending from Lexington south to West Durango Boulevard, RIO-3 includes the traditional Riverwalk "horseshoe" that still maintains many of the original features designed by architect Robert H. H. Hugman.
RIO-4
Extending from West Durango Boulevard south to Mission Road, RIO-4 meanders along the Arsenal, through the King William Historic District and south through a portion of the Mission Historic District.
RIO-5
Extending from Mission Road south to Southeast Military Drive, RIO-5 skirts the San Jose Mission complex.
RIO-6
Extending from Southeast Military Drive south beyond Southeast Loop 410 that includes the Mission Espada complex, RIO-6 has a distinctly rural character, consisting of rolling riparian prairie.
RIO-7
RIO-7 was established by City Council in October 2016. Following the extents of the San Pedro Creek Culture Park, RIO-7 extends from West Quincy Street downtown to West Lachappelle Street on the city's Southside.
The RIO-7 overlay districts respond to the unique height and scale of buildings established in related neighborhood plans and promote connectivity and pedestrian access to San Pedro Creek.
Viewshed Protection Districts
The purpose of a Viewshed Protection district is to establish regulations to protect, preserve and enhance views and vistas.
The City of San Antonio has many views and vistas of historic places, landmark buildings and other sites of cultural importance which have always been important to the city. These views will continue to be amenities and assets of great value to the city, its people and its economy.
Viewshed Protection districts are overlay districts that will be used primarily for unique situations regarding views and vistas that are not adequately covered by the standard zoning districts.
No part of a new structure, sign, tower, roof top equipment, or other appurtenance shall be permitted to encroach into any designated viewshed as set forth in this ordinance unless an encroachment was approved legally before the effective date of the Viewshed Protection ordinance.
If the maximum height allowed in any zoning district within the city differs from the height permitted by a protection district, the more restrictive height limitation shall apply.
Alamo Viewshed Protection District (VP-1)
San Antonio currently has one Viewshed Protection district. It lies behind the main entrance to the front door of the Mission San Antonio de Valero (The Alamo), a local Exceptional Landmark and a National Historic Landmark. A brass disc monument named VP-1, Alamo Viewshed, has been set to mark the viewpoint origination in Alamo Plaza in front of the Alamo Chapel.
The area above a plane described by the following boundary is designated as the Alamo Viewshed Protection District (VP-1):
Beginning at a point at elevation 663.22 feet above disk VP-1, Alamo Viewshed and extending through a point of the plane of the façade that is level with and six inches northwest from the topmost northern corner of the Alamo façade at a vertical angle of 9°34'38" and at a distance of 109.23 feet to the east right of way line of Interstate Highway 37 for the northern boundary of the viewshed (please refer to the UDC Section 35-337 for full boundary description).
Mission Protection Overlay Districts (MPODs)
Similar to a Viewshed Protection District, the MPODs were developed specifically for the four southern missions in consideration of the pending World Heritage Status for the sites
In order to protect these important community treasures, the City of San Antonio OHP developed the MPODs through public feedback.
The MPODs regulate building height within a 1,500-foot buffer area:
- Mission Concepcion
- Mission San Jose
- Mission San Juan
- Mission Espada