The reservoir that will help keep Prosper and Celina's taps running as both communities boom has finished construction and started collecting water.
Lake Ralph Hall, a new reservoir in Fannin County built by the Upper Trinity Regional Water District, officially began filling in early July after crews closed the intake structure gates, according to a UTRWD news release. The milestone caps five years of construction that began in June 2021.
At full capacity, the lake will deliver 54 million gallons of water per day to 29 North Texas communities, including Prosper and Celina, according to UTRWD documents.
Limited water delivery is expected to begin by the end of 2026. Filling the lake completely will take three to five years depending on rainfall.
Why it matters locally
Both towns are growing fast and straining existing water infrastructure. Celina enacted increased water-use restrictions on Thursday, July 2, to manage supply during peak summer months, and Prosper limits outdoor watering to twice a week through Saturday, October 31. Celina City Council expects to review additional water conservation ordinances this fall.
The lake is roughly the size of Grapevine Lake but deep enough to hold twice as much water, Jason Pierce, UTRWD manager of Governmental Affairs and Communications, told Community Impact in 2024.
Parallel investments
Lake Ralph Hall is one piece of a broader push to match water and wastewater capacity to the housing and commercial development filling both towns.
Prosper and Celina are coordinating with UTRWD on the $269 million Doe Branch Water Reclamation Plant expansion in Little Elm, which will increase wastewater treatment capacity from 4 million to 12 million gallons per day. That project is expected to finish in fall 2028.
Separately, Celina City Council on Tuesday, July 14, approved a $70.3 million contract with Drake General Contractors to expand the Downtown Water Reclamation Facility on North Florida Drive, Community Impact reported. The upgrade will triple the plant's processing capacity from 0.95 million gallons per day to 3 million gallons per day, with construction starting this fall and wrapping up in the second quarter of 2029.
Celina's average daily wastewater flow is projected to jump from 4.8 million gallons per day in 2024 to 17.4 million gallons per day by 2034, according to a July 2025 city study.
What's next
UTRWD said it will share updates as the lake fills. Future public amenities planned at the site include boat ramps, a fishing jetty, a hike-and-bike trail system, campsites, and a visitor center. Fishing and boating will become available as water levels rise.
Residents can track progress at lakeralphhall.com.
