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 six 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. It important to note that the RIO guidelines do not effect residentially zoned properties (up to 6 units).  Recent amendments to the RIO guidelines were approved by City Council on March 31, 2011.

RIO Amendments

RIO Guidelines

In reviewing an application for a certificate of appropriateness for properties in the six (6) River Improvement Overlay districts, the HDRC and the Office of Historic Preservation (OHP) consider the character and design objectives for each river improvement overlay district, as well as the design standards set forth in the UDC. There are also specific design standards for the Riverwalk specified in the UDC. For additional information, please refer to section 35-670 of the City of San Antonio's Unified Development Code (UDC) and the recent amendments at the link above or contact OHP staff for assistance.


Extending from Hildebrand Avenue south to US Highway 281 North, the northernmost of the six (6) RIO districts includes a mix of residential, commercial, and recreational uses.

The design objectives for RIO-1 are: to maintain the character of existing residential neighborhoods and redevelop commercial nodes; to encourage mixed use redevelopment of the urban character along Broadway and Avenue B; and to maintain scenic open space and the natural character of the river, particularly through Brackenridge Park.

RIO-1 Map


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.

The design objectives for RIO-2 are: to encourage high-density, mixed-use developments as extensions of the downtown core; to encourage neighborhood and cultural tourism oriented uses as well as those that provide additional housing for downtown workers; to enhance the pedestrian experience with high quality streetscape designs and links to the public Riverwalk; and to enhance the pedestrian experience with high-quality building designs that include balconies facing the river and primary entrances facing the street.

RIO-2 Map


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.

The design objectives for RIO-3 are: the historic work of Robert Hugman, CCC and WPA construction work, Ethel Harris tile work, and work of the National Youth Administration shall be respected and preserved in all construction efforts, and adherence to the intent and spirit of those plans is essential in all construction; traditional, formal street level design precedents shall be respected, but at the river level, the more informal, handcrafted style shall be maintained; the integrity of historic properties shall be preserved, and historic differences between street level designs and river level designs shall be respected; the traditional design context of the area shall be respected at two levels: the broader downtown context and the immediate block as it faces the river; the microclimate of the river walk level shall be maintained and, during construction, shall be given extra protection, and River operations staff will be consulted to provide specific instructions for construction procedures.

RIO-3 Map


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.

The design objectives for RIO-4 are: to encourage urban quality mixed-use developments; to preserve and enhance the historic character as well as emphasize the street scene; to construct new development that complements the nearby historic King William area but does not mimic its style; and to encourage new development in clustered nodes.

RIO-4 Map


Extending from Mission Road south to Southeast Military Drive, RIO-5 skirts the San Jose Mission complex.

The RIO-5 design objectives are: to maintain the residential character of the area while encouraging development of new mixed-use nodes that offer neighborhood shopping and services; and to respect established neighborhoods in new top-of-bank riverscape designs, particularly recreational opportunities that require parking or transport of recreational equipment.

RIO-5 Map


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.

The design objectives for RIO-6 are: to maintain the historic rural Texas character while encouraging development of new and mixed-use nodes; and to maintain the natural quality at the top of the riverbank using native plants and minimizing formally landscaped areas to preserve the natural character of the river.

RIO-6 Map

RIO-1 Brackenridge Wier

RIO-2 Museum Reach

RIO-3 Casa Rio

 RIO-3 Riverwalk

 RIO-4 King William

   RIO-5 Mission Espada Aquaduct