San Marcos Water Quality
Texas
According to EPA SDWIS, San Marcos, Texas is served by 5 community water systems covering about 137,288 people. The same extract lists 97 health-based violation records, most recently coded 2950 in 2025. Counts are historical EPA registry rows, not a current compliance or drinkability score.
Drinking water in San Marcos, Texas is delivered through 5 EPA-regulated community water systems serving an estimated 137,288 people. Each system is tracked in the EPA Safe Drinking Water Information System (SDWIS) under the Safe Drinking Water Act, which requires testing for regulated contaminants, consumer notification of violations, and publication of an annual Consumer Confidence Report.
PlainEnviro's health-based SDWIS extract shows 97 violation records across the 5 active community systems shown here. Monitoring and reporting records are not present in the extract. The records carry 5 distinct EPA contaminant codes: TTHM, Total Haloacetic Acids (HAA5), Long Term 2 Enhanced Surface Water Treatment Rule, Lead and Copper Rule, Surface Water Treatment Rule. 4 TRI-reporting industrial facilities are also located within the city limits.
A past EPA health-based registry row does not describe water delivered today or current compliance status; utilities notify customers and remediate under state primacy oversight when required. For current water-quality status and treatment practices, review your local utility's most recent Consumer Confidence Report or contact the Texas drinking water program. All records above reflect federal EPA SDWIS data and are not independently verified against state databases.
Community Water Systems
| System Name | Pop. Served | Violations | Status |
|---|---|---|---|
| CITY OF SAN MARCOS | 72,970 | 3 | Health |
| TEXAS STATE UNIVERSITY - SAN MARCOS | 43,552 | 1 | Health |
| CRYSTAL CLEAR SUD | 20,766 | 93 | Health |
| ALLIANCE REGIONAL WATER AUTHORITY 1B | 0 | 0 | Clean |
| ALLIANCE REGIONAL WATER AUTHORITY | 0 | 0 | Clean |
Does this city have health-based water violations?
These health-based records can represent Maximum Contaminant Level (MCL), Treatment Technique (TT), or Maximum Residual Disinfectant Level (MRDL) categories. A historical record does not establish that water is currently unsafe.
| Water system | Contaminant | Begin Date |
|---|---|---|
| CITY OF SAN MARCOS | TTHM | 2025-10-01 |
| CRYSTAL CLEAR SUD | TTHM | 2019-07-01 |
| CRYSTAL CLEAR SUD | TTHM | 2019-07-01 |
| CRYSTAL CLEAR SUD | Total Haloacetic Acids (HAA5) | 2019-07-01 |
| CRYSTAL CLEAR SUD | Total Haloacetic Acids (HAA5) | 2019-07-01 |
| CRYSTAL CLEAR SUD | TTHM | 2019-04-01 |
| CRYSTAL CLEAR SUD | TTHM | 2019-04-01 |
| CRYSTAL CLEAR SUD | Total Haloacetic Acids (HAA5) | 2019-04-01 |
| CRYSTAL CLEAR SUD | Total Haloacetic Acids (HAA5) | 2019-04-01 |
| CRYSTAL CLEAR SUD | TTHM | 2019-01-01 |
| CRYSTAL CLEAR SUD | TTHM | 2019-01-01 |
| CRYSTAL CLEAR SUD | Total Haloacetic Acids (HAA5) | 2019-01-01 |
| CRYSTAL CLEAR SUD | Total Haloacetic Acids (HAA5) | 2019-01-01 |
| CITY OF SAN MARCOS | TTHM | 2016-01-01 |
| CITY OF SAN MARCOS | TTHM | 2016-01-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2015-06-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2015-06-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2015-05-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2015-05-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2015-04-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2015-04-01 |
| TEXAS STATE UNIVERSITY - SAN MARCOS | Lead and Copper Rule | 2015-04-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2015-03-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2015-03-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2015-02-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2015-02-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2015-01-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2015-01-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-12-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-12-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-11-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-11-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-10-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-10-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-09-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-09-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-08-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-08-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-07-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-07-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-06-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-06-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-05-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-05-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-04-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-04-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-03-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-03-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-02-01 |
| CRYSTAL CLEAR SUD | Long Term 2 Enhanced Surface Water Treatment Rule | 2014-02-01 |
What are San Marcos's health-based records for?
San Marcos's health-based violation records carry 5 distinct EPA codes: some name a substance, others the drinking-water rule that was breached. Counts are records on file in the EPA SDWIS extract, not current test results.
| Contaminant | Records | Systems |
|---|---|---|
| Long Term 2 Enhanced Surface Water Treatment Rule | 78 | 1 |
| Tthm | 9 | 2 |
| Total Haloacetic Acids (HAA5) | 6 | 1 |
| Surface Water Treatment Rule | 3 | 1 |
| Lead and Copper Rule | 1 | 1 |
TRI Facilities in San Marcos
| Facility | Total Releases |
|---|---|
| Collins Aerospace San Marcos | 10.6K lbs |
| Pavestone - San Marcos Tx Plant | 1 lbs |
| Txi-San Marcos Ready Mix | 0 lbs |
| Cmc Steel Fabricators Inc. | 0 lbs |
Frequently Asked Questions
What does EPA SDWIS list for drinking water in San Marcos, Texas? ▼
How many water violations does San Marcos have in this EPA extract? ▼
What contaminants were found in San Marcos water? ▼
How many water systems serve San Marcos? ▼
Where does San Marcos get its drinking water? ▼
Are there pollution sources near San Marcos? ▼
How does San Marcos compare in Texas?
Of the 1,232 Texas places with at least one community water system on file, San Marcos ranks #117 by number of systems (5).
Either side of it: Pittsburg (5), Rockwall (5), Temple (5), Timpson (5)
About This Data
Figures here are the current EPA SDWIS extract joined to the 5 community water systems whose service area lists San Marcos, ranked against the 1,232 Texas places with at least one system on file. Data current as of 2026-08-25.
Water system data comes from the EPA's Safe Drinking Water Information System (SDWIS). PlainEnviro's violation fetch is restricted upstream to records EPA flags as health-based and then joined to active community water systems. Monitoring and reporting violations are not included.
A health-based violation row in this extract is a historical EPA registry entry. It does not describe water delivered today or current compliance status. Many records are later resolved, and public water systems notify customers when required. For current conditions, contact your local water utility or the state drinking water program.
TRI facility data comes from the EPA Toxic Release Inventory. Facilities shown are those that self-report to the TRI program. PlainEnviro presents this data without advocacy framing.
Read our methodology - how this data is sourced, computed, and verified.