San Marcos water and sewer rates
Who supplies water to San Marcos houses, what it costs, and how the sewer charge works.
City of San Marcos (SMTX Utilities)
inside-city rates for a 5/8 inch to 3/4 inch meter, billed monthly
| Use a month | Price per 1,000 gallons |
|---|---|
| Fixed charge | $34.36 a month |
| 0 to 6 thousand gallons | $5.76 |
| 6 to 9 thousand gallons | $10.09 |
| 9 to 12 thousand gallons | $11.54 |
| 12 to 20 thousand gallons | $12.98 |
| 20 to 50 thousand gallons | $14.42 |
| 50 to more | $17.28 |
- Source
- Edwards Aquifer wells, Carrizo-Wilcox Aquifer groundwater (Alliance Regional Water Authority) and Canyon Lake surface water pumped from Lake Dunlap.
- Lead
- The 90th-percentile lead result for 2022-2024 was 1.63 ppb; the action level is 15 ppb.
- Violation
- Total trihalomethanes (a disinfection byproduct) exceeded the limit as a running annual average in October-December 2025; the city is flushing parts of the system.
- Nitrate
- Highest nitrate result 1.77 ppm in January 2025; the limit is 10 ppm.
Sewer
Inside-city sewer for a 5/8 to 3/4 inch meter: a $32.40 minimum for the first 2,000 gallons, then $9.34 per 1,000 gallons. For 5/8-3/4 inch, 1 inch and 1 1/2 inch meters, residential sewer is based on average water use on the bills dated the previous December, January and February, and single-family homes pay nothing extra above 9,000 gallons.
Other charges on the utility bill
- Stormwater (typical residential, 1,980-3,363 sq. ft. of impervious cover): $15.76 a month
- Roadway lighting (once per account): $1.34 a month
Ways to pay less
- Watch winter water use. For 5/8-3/4 inch, 1 inch and 1 1/2 inch meters, residential sewer rates are based on average water use on the bills dated the previous December, January and February. How: Track your water use in the SMTX Utilities customer portal.
- Irrigation conversion rebate. For SMTX water customers with an account in good standing: rebates for converting spray zones to drip irrigation, removing irrigation zones or removing the whole irrigation system. How: Download the flyer and application from the city's Water Rebate Programs page.
Sources
- City of San Marcos Stormwater Utility Fee Information
- City of San Marcos 2025 Water Quality Report
- City of San Marcos Water & Energy Conservation
- City of San Marcos Water Rebate Programs
Checked October 20, 2026. Every number here comes from the public sources listed, matched by our checker.
Rates change every year; this page shows when it was last checked. Nothing here is legal, tax or insurance advice.