The Blanco River
The Comal River
The Frio River
The Guadalupe River
The Llano River
The Medina River
The Nueces River
The Pedernales River
The Sabinal River
The San Marcos River
See it for yourself — ask the community
A gauge gives you a number. Locals give you a photo. 40,000 people in our Texas Hill Country community post river shots, crossing updates and answers to “how’s the water?” every day.
Ask before you drive out, and share a photo when you’re there. It helps the next family decide.
Posting a river photo? Say which river, where, and what time you took it — that’s what makes it useful.
What the numbers mean
Flow — CFS
CFS means cubic feet per second: how much water moves past the gauge every second. One cubic foot is about 7.5 gallons, so a river running 100 cfs is pushing roughly 750 gallons past that spot every second.
Flow is the best single number for “how’s the river.” More cfs means more water, a faster current and more force against anything in its way, including a car at a low-water crossing.
Only compare a river to itself. 150 cfs can be a gentle current on one river and a strong one on another, because every channel is a different width and depth. Use each river’s 24-hour graph to see how today compares.
Gauge height — feet
Gauge height is not how deep the river is. It’s the height of the water surface measured against a fixed marker at the gauge. A reading of 3 ft doesn’t mean 3 ft deep; some gauges read a couple of feet even when the river is only ankle-deep.
What matters is the change. A gauge height climbing fast means a rise is on the way, which is why each river shows an arrow and a 24-hour graph.
The red levels on this page come from the National Weather Service: action stage is where they start watching a river closely, and flood stage is where water starts flooding land and roads near the gauge.
Water temperature
Only some USGS stations measure it. On this page that’s the Frio at Concan and the Nueces at Laguna. Spring-fed rivers like the Comal and San Marcos hold steady in the low 70s year-round.
Where the readings come from
Every number is live from U.S. Geological Survey gauges, which report about every 15 minutes. The readings are provisional and can be revised. Flood warnings come from the National Weather Service.
A gauge measures one spot. Water upstream, a side creek or a flooded crossing a mile away can be very different — check in person before you go, and never enter high or fast water.
Road closures & low-water crossings
Low-water crossings flood before the river looks high at the gauge. It only takes about a foot of moving water to float a car, and two feet to sweep away a truck. If water is over the road, turn around.
- DriveTexas — TxDOT’s live map of state highway closures and flooding. It doesn’t cover county roads.
- Hays County water crossings map — county emergency services map (Wimberley, San Marcos area).
- City of San Marcos low-water crossings — the city’s list of crossings and its live map.
- Comal County low-water closures map — County Road Department map.
- Kerr County road & bridge closures — the county’s closures table.
Bandera, Blanco, Llano and Uvalde counties don’t publish a live crossings map. Use DriveTexas, local news and your own eyes.