Water Distribution

Water distribution system engineering in Texas

A water distribution system carries treated water from the well, plant or tank to every customer and fire hydrant. It includes mains, valves, hydrants, storage tanks, booster pump stations and pressure reducing valves.

MES designs and models distribution systems for Texas utilities, municipalities and developers. We extend mains to new subdivisions and commercial sites, size lines for fire flow, and study how existing systems hold up as they grow. It is part of our water engineering work in Texas.

How Texas reviews water distribution design

TCEQ regulates public water systems under 30 TAC Chapter 290. Section 290.44 covers distribution:

• Pipes, tanks and pump stations follow current AWWA standards. New pipe must meet ANSI/NSF Standard 61.
• No new distribution line may be smaller than 2 inches. The state's minimum line sizes cover domestic flow only, not fire flow.
• The system must be designed to hold at least 35 psi at 1.5 gallons per minute per connection, and 20 psi under combined fire and drinking water flow where it provides fire protection.
• The top of the pipe must be below the frost line and at least 24 inches below ground.
• New water lines must sit at least 9 feet from wastewater lines, and fire hydrants at least 9 feet from any wastewater line.
• The system needs enough valves that repairs do not cut off service to a large area, enough blowoffs to flush it, and as few dead ends as possible.

A new public water system needs written TCEQ approval of its plans before construction. An existing system must notify TCEQ before a significant change. It must submit plans when a distribution change moves its connection count by more than 10%, leaves it short of required capacity, or ties into another public water system. In some cases, a city or other public body with its own review engineers can certify line work instead.

Local rules sit on top. The utility sets its own pipe materials and details. The fire code official sets the fire flow a site needs. Certificates of convenience and necessity from the Public Utility Commission of Texas set who may serve the land.

Common problems and how we solve them

Low pressure as the system grows. New demand at the far end of a system, or on high ground, can pull pressure below 35 psi. We model the system with the new demand and size the fix: a larger main, a loop, a booster station or more storage.

Fire flow that falls short. A main can serve homes well and still fail a fire flow test. We flow test hydrants near the connection, add the project to the model, and size the main or booster to hold 20 psi at the required flow. See how a fire flow analysis works for a Texas development.

Pressure that runs too high. Low ground below a tall tank can see high pressure, which strains pipe and plumbing. Pressure reducing valves and separate pressure planes bring it back into range.

Water that never reaches a meter. Older systems lose water to leaks and meter error. We compare what the system produces with what customer meters record, find where losses concentrate and plan the repairs.

Near Sweetwater, we provided construction-phase engineering while four miles of waterline moved clear of TxDOT work on IH-20. Customers kept water service through the work. We work across Texas, from the Panhandle to the Rio Grande Valley.

Common questions

What pressure must a Texas water distribution system hold?

It must be designed for at least 35 psi at every point, at 1.5 gallons per minute per connection. Where it provides fire protection, it must also hold 20 psi under combined fire and drinking water flow, under 30 TAC 290.44(d).

Does a water line extension need TCEQ approval?

It depends. A new public water system needs written approval before construction. For an existing system, plans are required when the change moves its connection count by more than 10%, leaves it short of required capacity, or ties into another public water system.

When should a water system be modeled?

Before the layout is fixed. A hydraulic model shows pressure and fire flow with the new demand added, so pipe sizes and any booster or storage needs are known before design. Call (214) 833-6748 to talk about your system.