Water Quality Testing

The above map shows the most recent sampling locations and E. coli numbers. The pictures, if clicked, will appear in full screen. Click here to view map in full screen.

In-House Surface Water Quality Sampling

BCRAGD has an in-house water quality monitoring program in which field technicians sample water quality of the Medina River, Medina Lake, and its tributaries quarterly to assess E.coli concentrations. During the summer months (June-August), water quality samples are taken biweekly in order to provide current and quality information to the public for recreational purposes. Samples are analyzed in our lab and results are posted to our website (see bottom of this page), the District’s Facebook, and local newspapers.

Escherichia coli is a group of bacteria that can be found in the intestines of mammals and birds. It is often used as marker for pollution in surface waters. While many strains are harmless, some strains of E. coli have been found to make humans sick. The Texas Commission on Environmental Quality (TCEQ) has set the standard for E. coli concentrations at 399 most probably number (MPN) of colonies per 100 mL of water (TAC 30 §307.7). If counts are above this level, no primary contact recreation should take place in the immediate area. Primary contact recreation includes any activities–such as swimming, skiing, tubing, etc.–that could lead to significant ingestion of the water. Even if sample counts are low, there is always a possibility that individuals can get sick from E. coli.

It is important to know there is always a possibility of infection from E. coli when swimming or participating in any water recreation in rivers, streams, and lakes. Never drink or ingest the water without proper disinfection, and always swim at your own risk.