Upper Trinity
Regional Water District

900 North Kealy Street
P.O. Box 305
Lewisville, Texas 75067
(972) 219-1228

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Regional Treated Water System

  •         Overview         
  •          Sources          
  •  Treatment  Facilities
  • TransmissionFacilities

Treated Water Supply

Created to ensure an adequate water supply for its Members and Customers in Denton and Collin Counties, Upper Trinity provides treated (drinking) water services on a wholesale basis to more than 20 cities, towns and utilities.  Each local utility system then delivers the drinking water to its many retail customers for residential, commercial, industrial and municipal uses.

Upper Trinity’s Regional Treated Water System (the “RTWS”) was established in 1998 to provide fresh, clean and dependable drinking water to its Members and Customers.  Using state-of-the-art technology and processes, Upper Trinity prides itself in delivering high quality drinking water - - holding ourselves to higher water quality standards than what is traditionally required by state and federal regulations.

To learn more about the Regional Treated Water System, please select tabs above—


Long-Term Water Supply Sources

Because ground water (water from wells) is so limited in this region, the most reliable source of water today, and for the future, is surface water (water from lakes).  Therefore, to provide a reliable, secure and adequate water supply for this region, Upper Trinity has developed a comprehensive and diversified portfolio of water supply sources.  Present supplies are adequate for about 25 years, and additional water is needed to extent the water supply to 50 years.


Upper Trinity's Diversified Water Portfolio
 Local water in Lewisville Lake and Ray Roberts Lake
 Chapman (Cooper) Lake in northeast Texas
 Reuse of water from water reclamation plants
 Proposed Lake Ralph Hall in Fannin County
 Possible additional water from Sulpher River Basin
 Proposed purchase of additional water from the City of Dallas


Water from Chapman Lake is delivered through a jointly owned pipeline operated by the City of Irving.  A portion of Upper Trinity’s flows from Chapman Lake will be delivered to the new Tom Harpool Water Treatment Plant in northeast Denton County, and a portion will be discharged into Lewisville Lake for the regional treated water plant in Lewisville.  The below map illustrates Upper Trinity’s current and future water supply sources.




These water supply sources will be adequate for about 25 years, after which time new water supplies will be needed.  More water conservation and more reuse of existing supplies are part of the answer.  However, additional water sources are absolutely critical.  Upper Trinity plans to develop a new source of water in Fannin County - - Lake Ralph Hall.

Lake Ralph Hall, a proposed new water supply lake along the North Sulphur River in Fannin County will provide a safe, reliable water source for the families and cities that depend on Upper Trinity.  It is the most feasible and lowest cost source of new water available to Upper Trinity, and it can be built in time to avoid a water shortfall in about 25 years.

For more information about Lake Ralph Hall, click here.


Treatment Facilities

Water Treatment Plants. Upper Trinity constructed its first water treatment plant in Lewisville, Texas in 1997 - - the Regional Treated Water Plant. In order to meet the growing needs of its customers, Upper Trinity began the construction of its second water treatment plant in 2005 - - the Tom Harpool Regional Water Treatment Plant.

Regional Treated Water Plant, Lewisville.  Treating to its full 20 million gallon per day (MGD) capacity the first year of operation, this water treatment plant was expanded to 70 MGD in 2001.  Plant features include:

  • Ozone as a primary disinfectant resulting in improved destruction of bacteria and viruses, fewer chlorination by-products, and removal of taste and odor components from lake algae and blooms.
  • Granular activated carbon is used in the filter beds to remove organic compounds, including pesticides and herbicides.
  • Flocculation slows the mixing and coagulation of solid material without using electrical power.
  • State-of-the-art computer systems are used to monitor transmission flows, elevations in storage facilities and customer demand levels.

Tom Harpool Regional Water Treatment Plant. The Tom Harpool plant will provide treated drinking water to communities and utilities in northeastern Denton County and western Collin County. The new plant will also provide a future back up to the existing regional water treatment plant in Lewisville. Employing the latest in membrane technology, this plant will provide high quality drinking water.

The initial phase of the new Tom Harpool plant will have a capacity of 20 MGD.  The plant layout has been designed to accommodate future expansions when needed by Upper Trinity’s Members and Customers to a total capacity of approximately 240 MGD.  Plant features include:

  • Membrane filters that will perform multiple functions - - reduce turbidity, remove harmful pathogens and reduce the amount of organic carbon in combination with the coagulant.  The membrane barrier can range from 0.01 to 0.1 microns.
  • A clear well to provide storage of finished water.  It will be a 4 million gallon circular, cast-in place tank.
  • A pump station to pump the treated water into the distribution system.

This is a typical process for how water from lakes is treated and distributed to cities and utilities for them to provide to local residents and homeowners.


Transmission Facilities

Upper Trinity’s water transmission facilities include many miles of pipelines transporting water to its Members and Customers, two pump stations and three storage facilities.  All of these facilities, and treatment plants, are a part of Upper Trinity’s Regional Treated Water System, and transport dependable, high quality drinking water to its Members and Customers.


Transmission pipelines.  Upper Trinity has many miles of pipelines transporting drinking                                         water to  customers  in  Denton and Collin Counties. The                                         transmission pipelines extend from Justin to Celina and from                                         Flower Mound to Sanger.

 Stone Hill Pump Station.  Located in Flower Mound, the Stone Hill Pump Station includes                                         two ground storage tanks and a pump station to deliver water to                                         Upper Trinity’s customers in the western portion of its service                                         area.

 Elevated Storage Tank / Booster Pump Station. This elevated storage tank and booster                                         pump station is used  to boost system pressures for extra peak                                         demands.

 Temple Dane Pump Station. To provide drinking water to its customers in the northern                                         portion of the service area, Upper Trinity partnered with Mustang                                         Special Utility District to construct a joint pump station and a 1                                         million gallon storage facility.