San Marcos, TX Tap Water Quality

The drinking water in San Marcos, TX generally meets all federal health standards, earning a solid B grade with a composite safety score of 83/100 across 2 ZIP codes. While the primary water utility, City of San Marcos, maintains adequate compliance with EPA regulations, there have been minor or administrative violations on record. Overall, residents receive safe tap water that is actively monitored by Texas Commission on Environmental Quality (TCEQ).

A major factor in San Marcos's high rating is its flawless health-based violation record. Over the past 5 years of EPA tracking, local water systems have recorded zero health-based violations. This means that regulated contaminants—such as lead, arsenic, and harmful bacteria—have not exceeded the Maximum Contaminant Levels (MCLs) allowed by federal law. Drawing primarily from surface water, the city utilizes advanced filtration to maintain this standard.

Fortunately, the modeled risk for widespread lead exposure in San Marcos's municipal water is relatively low compared to national averages. However, because lead typically enters drinking water through the corrosion of older, individual home plumbing rather than the main supply lines, residents in homes built before 1986 should still exercise caution by running the tap before use.