San Antonio River Authority logo

Water Quality

The San Antonio River Authority (SARA) has been gathering water quality data in the San Antonio River Basin for approximately 40 years. Currently, SARA collects water quality data at more than 50 locations within the basin, with weekly E. coli bacteria data collection at eight sites along the San Antonio River. The data has established that the most widespread water quality problem within the San Antonio River Basin is high levels of bacteria after rain events.

When rain falls directly on undisturbed natural surfaces, the soils, rocks, plants, and their root systems help 1) to filter out bacteria and pollutants before they reach our rivers, creeks, and streams and 2) to slow down the water as it travels through the basin, reducing the bacteria- and pollution-carrying sediments that are picked up and deposited into our water ways.

However, much of our rain falls on rooftops, streets, sidewalks, and other such surfaces—as well as on farm- and ranch-land where fertilizers, animal feed, and animal wastes are not adequately buffered from our rivers, creeks, and streams. This water, called runoff, carries bacteria and bacteria-promoting materials into our basin’s waterways.

Since this is a common problem in most basins within the state, recreationists who plan to do river-related activities in any basin should research that basin’s bacteria levels before engaging in contact recreation.

To plan for your San Antonio River Basin excursion, click on the line graph links to view a table that reflects the last 10 samples for E. coli bacteria at the eight San Antonio River sites referenced above.

Contact us for more information about the water quality in the San Antonio River Basin. For more information about the relationship between E. coli bacteria and disease-causing organisms, click here.

Station ID Station Name Bacteria Collection Time E. coli Bacteria Result
S0069 San Pedro Creek Culture Park (San Pedro Creek immediately downstream of tunnel inlet) 11/14 at 3:15 PM 380 mpn
Line Graph
14256 San Antonio River at Mitchell Street, San Antonio, TX 11/14 at 2:53 PM 220 mpn
Line Graph
17066 San Antonio River at Mission Road, San Antonio, TX 11/14 at 2:37 PM 210 mpn
Line Graph
12897 San Antonio River at Interstate 410 Camino Coahuilatechan, San Antonio, TX 11/14 at 1:46 PM 250 mpn
Line Graph
12881 San Antonio River at SH 97 near Floresville, TX 11/14 at 12:38 PM 650 mpn
Line Graph
12879 San Antonio River at FM 791 S.W. of Falls City, TX 11/14 at 11:56 AM 600 mpn
Line Graph
12791 San Antonio River at US Hwy. 77-A, Goliad, TX 11/14 at 9:27 AM 2000 mpn
Line Graph
14211 Cibolo Creek at CR389 near Cestohowa, TX 11/14 at 10:57 AM 820 mpn
Line Graph
MPN—Most Probable Number (Colonies in 100 ml of water)
NA—Data is not currently available

Contact Recreation Standard

Contact Recreation is defined by the Texas Commission on Environmental Quality (TCEQ) under the Texas Administrative Code Title 30; Part 1; Chapter 307; Rule § 307.7:

(b) Appropriate uses and criteria for site-specific standards are defined as follows.
(1) Recreation. Recreational use consists of two categories—contact recreation waters and noncontact recreation waters. Classified segments are designated for contact recreation unless elevated concentrations of indicator bacteria frequently occur due to sources of pollution which cannot be reasonably controlled by existing regulations or contact recreation is considered unsafe for other reasons such as ship or barge traffic. In a classified segment where contact recreation is considered unsafe for reasons unrelated to water quality, a designated use of noncontact recreation may be assigned criteria normally associated with contact recreation. A designation of contact recreation is not a guarantee that the water so designated is completely free of disease-causing organisms. Indicator bacteria, although not generally pathogenic, are indicative of potential contamination by feces of warm blooded animals. The criteria for contact recreation are based on these indicator bacteria, rather than direct measurements of pathogens. Criteria are expressed as the number of “colony forming units” of bacteria per 100 milliliters (ml) of water. Even where the concentration of indicator bacteria is less than the criteria for contact recreation, there is still some risk of contracting waterborne diseases. Additional guidelines on minimum data requirements and procedures for evaluating standards attainment are specified in the latest approved version of the TCEQ Guidance for Screening and Assessing Texas Surface and Finished Drinking Water Quality Data.
(A) Freshwater
(i) Contact recreation. The geometric mean of E. coli should not exceed 126 per 100 ml. In addition, single samples of E. coli should not exceed 399 per 100 ml. Contact recreation applies to all bodies of freshwater except where specifically designated otherwise in §307.10 of this title.[/toggle]

So, What Does Contact Recreation Standard Mean

First let’s look at what contact recreation really means. Contact recreation means swimming or other activities involving direct contact. Contact recreation is an activity in which you are likely to have your head in the water and so increase your chances of swallowing some of that water. Contact recreation is also wading by children (they are more likely to get water in their mouth by splashing or drinking), water skiing, diving, and surfing. Contact recreation is not boating, canoeing, kayaking, or “limited body contact incidental to shoreline activities”, which could mean wading by adults.

Now, the statement by the TCEQ (which comes from the Environmental Protection Agency or EPA) is saying that if you are engaged in contact recreation you have some risk of contracting a waterborne illness (you could get sick). It also states that there is no testing being done that directly measures any disease-causing pathogens (bacteria, viruses, fungus etc.) that can cause waterborne illnesses. The reasons disease-causing pathogens are not measured directly is because there are many different kinds of organisms and they are very hard to measure. So, the next best thing is to measure something else, an “indicator bacteria”, that can be associated with those pathogens. That indicator bacteria is E. coli, an organism found in the feces of all warm-blooded animals. The statement says it’s more likely that pathogens (disease-causing organisms) are going to be present if the indicator bacteria (organisms that are not usually disease-causing) are there. Statistics tell us that if the indicator bacteria are above a certain level there is a better chance that pathogenic organisms will be there. As the number of indicator bacteria go up so does the chance of finding pathogens. However, it also warns that just because the number of indicator bacteria is below the standard it “is not a guarantee that the water so designated is completely free of disease-causing organisms”. Another way to say this is that there can NEVER be a guarantee that anything is completely safe including swimming in crystal clear water with extremely low numbers of indicator bacteria.