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San Marcos River at San Marcos water level

River gauge, San Marcos River, Texas, United States

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Right now

Low for mid-October

Water level

3.67ft Steady over the last 24 hours

Flow
94.9 cfs
10 20 Highest onrecord 21.29 ft

History

History
45ftOct 12Oct 13Oct 15Oct 17Oct 1845ftOct 12Oct 15Oct 18
45ftSep 19Sep 26Oct 3Oct 11Oct 1845ftSep 19Oct 3Oct 18
456ftOct 2025Jan 2026Apr 2026Jul 2026Oct 2026456ftOct 2025Apr 2026Oct 2026
456ftJanMarMayJulSepNov2026456ftJanAprJulOct2026

20252026

Water level Normal range (10–90 %)

What this means

At 3.67 ft, the San Marcos River at San Marcos is below normal for mid-October.

The median for mid-October is 4.66 ft, based on 30 years of readings, so the river stage is 0.99 ft below typical. On the same day last year the reading was 3.53 ft, a difference of +0.14 ft.

It has barely moved over the past 24 hours. Without real rain upstream, that is unlikely to change quickly. Over the past 30 days it has moved between 3.59 ft and 3.76 ft.

Fall is often low-water season on rivers, and it usually takes a few days of steady rain to change that.

Compared with 30 years of daily readings for this time of year. How to read levels

Key numbers

Median for this date
4.66 ft0.99 ft below the median for this date
Normal for this date
3.46 ft – 5.37 ft8 years in 10 fall in this range (30 years of records)
Same day last year
3.53 ft+0.14 ft
Lowest and highest in 30 days
3.59 ft – 3.76 ft
Lowest and highest in 12 months
3.47 ft – 4.11 ft
Highest on record
21.29 ftOctober 17, 1998

What the stage means on the water

Low water means more dragging on shallow riffles and slower floats. Fish crowd into the deeper runs, and warm, low water stresses them, so play and release them quickly.

Highest crests on record

RankLevelDate
121.29 ftOctober 17, 1998
210.77 ftJuly 8, 2002

Weather at the gauge

The forecast is not available right now.

Sunrise 07:36 AM Sunset 06:59 PM Daylight 11 hr, 23 min First quarter 53%

Map

Other gauges on the San Marcos River

Gauge Level Compared with normal 24 hours Distance
San Marcos River near MartindaleRiver gauge, San Marcos River 7.40 ft Normal −0.03 ft 7 mi
San Marcos River at LulingRiver gauge, San Marcos River 3.66 ft Very low +0.01 ft 23 mi

Nearby gauges

Gauge Level Compared with normal 24 hours Distance
Blanco River at San MarcosRiver gauge, Blanco River 7.19 ft Below flood stage −0.20 ft 1.6 mi
Blanco River near KyleRiver gauge, Blanco River 26.18 ft Very high ±0 6 mi
Blanco River at Halifax Rch near KyleRiver gauge, Blanco River 0.83 ft Low −0.02 ft 8 mi
Blanco River at WimberleyRiver gauge, Blanco River 3.51 ft Low +0.01 ft 12 mi
Onion Creek near DriftwoodRiver gauge, Onion Creek 1.14 ft Normal −0.02 ft 14 mi
Guadalupe River at SattlerRiver gauge, Guadalupe River 4.45 ft Normal ±0 15 mi
Guadalupe River at Third Crossing near SattlerRiver gauge, Guadalupe River 3.81 ft Normal +0.01 ft 15 mi
Hueco Spgs near New BraunfelsRiver gauge, Hueco Spgs 7.14 ft Normal +0.01 ft 15 mi

Questions and answers

Is the San Marcos River at San Marcos higher than last year?

Yes, it is 0.14 ft higher than on the same day last year, when the reading was 3.53 ft.

What is a normal level for the San Marcos River at San Marcos in mid-October?

The median for mid-October is 4.66 ft. In 8 years out of 10 the reading falls between 3.46 ft and 5.37 ft, based on 30 years of records.

Is gage height the same as water depth?

No. Gage height is measured from a fixed reference point chosen by the agency, so a reading of 10 ft does not mean the river is 10 ft deep.

What is the water level of San Marcos River at San Marcos today?

On Oct 18, 2026, 03:45 PM CDT, the water level was 3.67 ft. Steady over the last 24 hours.

Is San Marcos River at San Marcos rising or falling?

Steady over the last 24 hours. Steady over the last 7 days.

Is the level of San Marcos River at San Marcos normal?

Low for mid-October. Compared with 30 years of daily readings for this time of year.

What is the highest water level ever recorded at San Marcos River at San Marcos?

The highest level on record is 21.29 ft on October 17, 1998.

For specialists

Station codes, datum, parameters, data quality and downloads
Operator
U.S. Geological Survey
Station code
usgs:08170500 (Agency page)
Coordinates
29.88911, -97.93417 (WGS84)
Vertical datum
NAVD88
Update interval
every 15 minutes
Licence
Public domain. Data: U.S. Geological Survey (USGS), provisional data subject to revision

Published series

ParameterLast valueTime (UTC)Quality
Water level 3.67 ft 2026-10-18 20:45 Provisional
Flow 94.9 cfs 2026-10-18 20:45 Provisional

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How to cite

U.S. Geological Survey: San Marcos River at San Marcos (usgs:08170500). Accessed October 18, 2026 via Nivelmap, https://nivelmap.com/en/united-states/texas/san-marcos-river-at-san-marcos

How we check values

Each reading is stored as published. We hold back values that jump faster than physically plausible and show the measurement time with every value.