Where Texas water comes from
Texas runs on two main sources: surface water from rivers and reservoirs, and groundwater from aquifers like the Edwards, Trinity, Carrizo-Wilcox, Gulf Coast, and Ogallala.
Atlas TX · education
Texas water system guide.
A grounded primer on where Texas water comes from, how it moves, who governs it, and why county-level water risk is uneven. This page stays aligned with Atlas TX taxonomy: source systems, environmental burden, infrastructure/fiscal capacity, and community context. It also introduces key agencies like Texas Commission on Environmental Quality (TCEQ) and Texas Water Development Board (TWDB) plus system terms like Public Water System (PWS).
Common education terms
Texas Commission on Environmental Quality (TCEQ)Texas Water Development Board (TWDB)Public Water System (PWS)National Flood Hazard Layer (NFHL)Hydrologic Unit Code (HUC)
The four core questions
Start here before looking at county rankings, PWS risk, or basin overlays.
How water moves
Rain refills rivers, lakes, and aquifers. Utilities and districts withdraw, treat, deliver, collect wastewater, then either discharge treated water back to rivers or reuse it.
Who manages it
Texas has no single statewide water system. TWDB plans, TCEQ regulates, and river authorities, groundwater districts, utilities, and water districts run the local supply chain.
Why risk varies by county
Water stress depends on drought, reservoir storage, aquifer levels, flood damage, treatment capacity, infrastructure age, growth, and upstream-downstream dependence — not just whether water is nearby.
Texas water system at a glance
A simple map of the flow: rainfall and recharge feed both surface water and groundwater, utilities treat and deliver that water, and wastewater systems return or reuse it.
☁
Step 1
Rain + recharge
Rainfall feeds rivers, reservoirs, soils, springs, and aquifer recharge zones.
≈
Step 2
Surface water
Rivers and reservoirs supply many regional systems through intakes, storage, and treatment plants.
◌
Step 3
Groundwater
Aquifers support municipal wells, private wells, and many rural or edge-community systems.
▣
Step 4
Treatment + delivery
Utilities treat raw water and move it through tanks, pumps, and pipes to homes and businesses.
↺
Step 5
Wastewater + reuse
Used water is collected, treated, and either discharged back to rivers or reused where systems allow.
≈
Surface water
Water stored or flowing above ground in rivers, lakes, reservoirs, and streams. This is the backbone for many larger Texas cities and regional systems.
Examples
- • rivers
- • reservoirs
- • lakes
- • stream intakes
Strengths
- • can serve large populations through regional treatment plants
- • easier to visualize in basin and reservoir maps
- • often tied to major inter-county infrastructure
Watchouts
- • drought lowers inflows and storage
- • floods can disrupt intakes and treatment operations
- • upstream withdrawals and discharges matter
◌
Groundwater
Water pumped from underground aquifers such as the Edwards, Trinity, Carrizo-Wilcox, Gulf Coast, and Ogallala. It is critical for rural systems, wells, and fast-growing edge communities.
Examples
- • municipal wells
- • private wells
- • aquifer pumping
- • spring-linked systems
Strengths
- • can support smaller local systems without major reservoirs
- • often buffers short-term surface drought shocks
- • important for rural and dispersed communities
Watchouts
- • declining aquifer levels can raise long-term risk
- • recharge can lag behind demand growth
- • well reliability and local geology vary sharply by county
How water moves through Texas
- 1Rainfall and recharge refill rivers, reservoirs, wetlands, and aquifers.
- 2Water rights, pumping access, and district rules determine who can withdraw it.
- 3Utilities, districts, and authorities treat and deliver water to homes, farms, and businesses.
- 4Wastewater systems collect used water, treat it, then discharge or reuse it.
Who governs it
Layer 1
State planning
TWDB handles long-range supply planning, drought strategy, and infrastructure funding.
Layer 2
State regulation
TCEQ oversees permits, water quality, and public-water-system regulation.
Layer 3
Regional control
River authorities and groundwater conservation districts manage basin and aquifer realities on the ground.
Layer 4
Local delivery
Cities, utilities, water districts, and private operators treat and move the water people actually use.
Why county water risk is uneven
A county can sit near rivers, reservoirs, or major aquifers and still face water stress. Atlas TX treats these as interacting signals rather than a single supply score.
surface-water dependence vs aquifer dependence
reservoir storage and drought exposure
treatment and distribution capacity
flood damage and infrastructure fragility
population growth and demand pressure
upstream / downstream dependence
Glossary
Plain-English definitions for the agencies, datasets, and regulatory acronyms used across Atlas Texas.
ACS
American Community Survey
APO
Aggregate Production Operation
CID
Commissioners’ Integrated Database
DWRS
Drinking Water Risk Score
EJ
environmental justice
EJScreen
EPA Environmental Justice Screening and Mapping Tool
EPA
Environmental Protection Agency
FEMA
Federal Emergency Management Agency
GBRA
Guadalupe-Blanco River Authority
HUC
Hydrologic Unit Code
LCRA
Lower Colorado River Authority
NFHL
National Flood Hazard Layer
PWS
Public Water System
SDWIS
Safe Drinking Water Information System
SOAH
State Office of Administrative Hearings
TCEQ
Texas Commission on Environmental Quality
TWDB
Texas Water Development Board