A team of about 600 water professionals in the Drinking Water Operations (DWO) Branch, ensures that approximately 5.5 million citizens receive high quality drinking water at sufficient pressure to meet their daily needs. Composed of a variety of technical groups, DWO is staffed and resourced to meet this challenge every day, 24/7. DWO is responsible for protecting our regional water supply, operating and maintaining three water purification plants and 49 ground water plants. Houston’s water system spans over 600 square miles serving four counties, therefore, making it one of the most complex water systems in the nation.

Water operators and maintenance crews work around the clock to ensure the facilities and systems are in good working order. Licensed operators collect water samples throughout our drinking water system for analysis by our nationally accredited laboratory. Field investigators and technical staff respond promptly to customer water quality questions or concerns.

Water Quality and Public Health

Houston Drinking Water Meets or Exceeds Federal and State Regulations

Our number one priority is protecting public health by supplying citizens with high quality drinking water. DWO water professionals proudly produce some of the best quality drinking water in the nation and continually meet or exceed state and federal drinking water regulations. The Texas Commission on Environmental Quality (TCEQ) rates the City of Houston’s drinking water system as a “Superior Water Supply System,” which is the highest water quality rating awarded to a water utility.

For more information regarding the quality of our water, read the Annual Consumer Confidence Report contained on our website.

The City of Houston is a member of the American Water Works Association (AWWA) and AWWA's Partnership for Safe Water program for both treatment plant and distribution system optimization. This program is based on voluntary commitments above and beyond regulatory requirements to improve the quality of water delivered to customers by optimizing water system operations

Source Water

Source Water Protection is the practice of monitoring and assessing the quality of our water resources, and implementing programs that reduce pollutants and chemical contaminants which could potentially negatively impact these resources. Protecting water resources from contaminants also eliminates the need for supplementary treatment procedures and can delay the cost of new infrastructure and related increases in water rates.

Local lakes and rivers supply the City of Houston surface water resources. Eighty-six percent of our supply flows from the Trinity River into Lake Livingston, and from the San Jacinto River into Lake Conroe and Lake Houston. Deep underground wells drilled into the Evangeline and Chicot aquifers currently provide the other 14 percent of the City’s water supply. 

For information about how we protect our source water, visit the Drinking Water Regulatory Compliance webpage. 

Water Transmission, Purification and Distribution

The City of Houston is the regional water provider for Harris County and portions of the three surrounding counties. The City of Houston has sufficient water supplies for its wholesale and retail customers through approximately the year 2050 through a combination of over 1.2 billion gallons per day of reliable surface water rights and over 200 million gallons per day (MGD) of available groundwater supplies.

Groundwater supply quantities are defined as sustainable aquifer yield (groundwater rights do not exist in Texas), and in our region they are determined by the regulations of the Harris Galveston Subsidence District. Surface water rights are defined as reliable or unreliable. Reliable rights will exist during the worst drought on record, which for the Houston region extended over a seven-year period during the 1950’s. Unreliable rights will not be available during the worst drought on record. The City of Houston’s reliable surface water rights consist of a combination of reservoir and run-of-river yield from Lake Livingston, Lake Houston and Lake Conroe and from river flows within the lower Trinity River. The City of Houston has additional water rights applications pending before the Texas Commission on Environmental Quality (TCEQ). The goal is to acquire sufficient rights to meet the future 50-year water demand projections for all City wholesale and retail customers.

The City of Houston owns a 70% share of Lake Livingston, a 70% share of Lake Conroe, 100% of Lake Houston. The City of Houston uses other water agencies to manage operations and maintenance of our lake supplies. Lake Livingston is operated and managed by the Trinity River Authority, Lake Conroe is managed by the San Jacinto River Authority (SJRA) and the Coastal Water Authority manages Lake Houston. The City of Houston will own a 70% share of the future Allen's Creek Reservoir project, which the Brazos River Authority will manage. It is not planned for use until approximately the year 2025.

Surface water is piped or gravity-fed to one of three DWO surface water purification plants to be treated and disinfected. After the water is tested and meets state and federal drinking water standards, it is delivered to customers throughout a four-county area.

Groundwater is pumped from wells that are on average 1,200 feet deep. Groundwater is pumped to one of seven surface water re-pressurization plants, treated and distributed to customers predominately in the west side of Houston.

Houston's Drinking Water Operations produced and distributed more than 172 billion gallons of water in 2021 through an over 7,000-mile pipeline distribution system.