City of San Marcos

The City of San Marcos Water/Wastewater Utilities strives to provide residents with safe, reliable municipal water. Our supply comes from both surface and groundwater sources - specifically the Edwards Aquifer (South BFZ) and Canyon Lake.

We hope this information helps you better understand what's in your tap water. If you have questions or would like to request a meeting about your water quality, please contact our Water Quality Manager at (512) 393-8038.

Municipal water sources include rivers, lakes, streams, ponds, reservoirs, springs, and wells. As water travels over land or through the ground, it dissolves naturally-occurring minerals and, in some cases, radioactive materials, and can pick up substances from animal presence or human activities.

The Texas Commission on Environmental Quality is currently updating a Source Water Susceptibility Assessment for our water sources. This information describes the susceptibility and types of constituents that might affect your water supply based on human activities and natural conditions. For more information about your sources of water, please visit the Source Water Assessment Viewer at https://www.tceq.texas.gov/gis/seaview.

All water, including bottled water, may reasonably contain at least small amounts of some contaminants. The presence of contaminants doesn't necessarily indicate a health risk. For more information about contaminants and potential health effects, call the EPA's Safe Drinking Water Hotline at (800) 426-4791.

To ensure tap water safety, EPA regulations limit certain contaminants in public water systems. FDA regulations establish similar limits for bottled water to provide equal public health protection.

Some water contaminants may cause taste, odor, or color issues without posing health concerns. For questions about water taste, odor, or color, please call us at (512) 393-8010.

Potential source water contaminants before treatment include:

• Microbial contaminants such as viruses and bacteria from sewage treatment plants, septic systems, agricultural operations, and wildlife
• Inorganic contaminants like salts and metals that occur naturally or result from urban runoff, industrial/domestic wastewater discharges, oil/gas production, mining, or farming
• Pesticides and herbicides from agriculture, urban stormwater runoff, and residential uses
• Organic chemical contaminants including synthetic and volatile organic chemicals from industrial processes, petroleum production, gas stations, urban runoff, and septic systems
• Radioactive contaminants that occur naturally or result from oil/gas production and mining

If present, elevated lead levels can cause serious health problems, especially for pregnant women and young children. Lead primarily comes from materials associated with service lines and home plumbing. While we're responsible for providing quality water, we can't control plumbing component materials. When your water has been sitting for several hours, minimize potential lead exposure by flushing your tap for 30 seconds to 2 minutes before using water for drinking or cooking. If concerned about lead, consider having your water tested. Information about lead in water, testing methods, and exposure reduction steps is available from the Safe Drinking Water Hotline or at http://www.epa.gov/safewater/lead.

1. How often is San Marcos water tested for contaminants?
2. What causes the hardness in San Marcos municipal water?
3. Are TTHMs in water a health concern for residents?
4. How does surface water sourcing affect our water quality?
5. What home filtration systems work best with San Marcos water?