Coastal Water Authority Raw Water Contracts: What Industrial Users in the Houston Ship Channel Need to Know

What is the Coastal Water Authority, and what does it deliver?

A raw water conveyance district serving Houston, two other cities and about 100 industrial and agricultural customers. According to the Coastal Water Authority's own site, it is a conservation and reclamation district created by a special act of the Texas Legislature in 1967. It operates in Harris, Chambers and Liberty Counties.

CWA provides untreated surface water to the cities of Houston, Baytown and Deer Park for municipal use, and to roughly 100 industrial and agricultural customers. A seven-member board governs it: four directors appointed by Houston's mayor and one appointed by the Governor from each of the three counties.

Its facilities include the Trinity River and Lake Houston systems, the Main Canal, the Lynchburg Pump Station and the Bayport Water System. The Luce Bayou Interbasin Transfer Project, finished in 2020, moves Trinity River water to Lake Houston through the 500 MGD Capers Ridge Pump Station.

Why is raw water a site selection question?

Because the connection, not the contract, often decides whether a parcel works. A parcel near CWA's canal or pipelines may need only a short lateral. A parcel farther out may need its own pipeline, easements and pumping before the first gallon arrives.

Treat raw water access like rail or pipeline access in the site study. Ask CWA early where a delivery point could go, what pressure and rate it can supply there, and who builds and owns the line from that point to your fence.

How do you size the contract quantity?

From a water balance by use, not a single plant-wide number. Build the demand up from each use:

• cooling tower makeup, often the largest use on a Ship Channel site
• process water, by unit and by product rate
• boiler feed, after its own treatment losses
• fire water fill and refill
• wash-down, utility and any potable use, if the facility treats its own

Add treatment losses for each stream, such as filter backwash and reverse osmosis reject, because they come out of the raw water you buy. Then size for peak months, not averages, since cooling demand peaks in the Houston summer. Run the balance again for the expansion you might build, so the contract has room or a defined way to add it.

What treatment does untreated water need before use?

A different train for each use, designed from your own delivery point data. Cooling makeup may need only clarification and chemical treatment. Boiler feed and many process uses need far more, and drinking water inside the fence brings TCEQ public water system rules if the facility serves its own people.

Surface water quality moves with the seasons and with storms. Sample at or near your actual delivery point across wet and dry periods, and design for the bad months. A treatment train designed from one good sample is an easy miss.

How do cooling cycles and reuse change what you buy?

Each cycle of concentration you add cuts makeup and blowdown at the same time. A tower that concentrates its water more times evaporates the same amount but sheds less blowdown, so it buys less raw water and discharges less wastewater. The raw water's hardness, silica and chloride set how far you can push it.

Treated process wastewater can sometimes return as tower makeup or wash water. Check that before the contract quantity is final. Our post on reuse versus discharge walks through the same tradeoff for Texas projects.

What happens to the supply in a drought?

Read the curtailment terms as closely as the price. CWA also delivers raw water to cities for public supply, so ask for its drought contingency plan and how that plan treats industrial contracts.

Texas sets a floor for wholesale water suppliers. Under 30 TAC §288.22(a)(7)(A), their drought plans must provide for pro rata curtailment of deliveries to wholesale customers as provided in Texas Water Code §11.039. Section 288.22(a)(8) requires wholesale contracts entered or renewed after the plan's adoption to say so.

Whether that framework reaches an industrial raw water contract, or the contract sets its own terms, is a question for the contract and the supplier. For a continuous process plant, also decide how many days of on-site raw water storage the process needs to ride through a cut or an outage.

Why does the wastewater plan belong in the same study?

Because every gallon you buy leaves as product, vapor or wastewater. Blowdown, treatment reject and process wastewater all need a home. That is a TPDES discharge, a sewer connection with pretreatment, or deep well injection, each with its own permit path and limits.

The receiving water and discharge limits can constrain the cooling cycles and reuse you planned. Our post on how TCEQ sets effluent limits explains where those limits come from. Close the water balance in both directions before you commit to a contract quantity.

What should be settled before you sign?

Seven answers. If any is still a guess, you are not ready to sign:

1. A water balance by use, at peak month and at the planned expansion
2. The delivery point, rate and pressure, and who builds the line to your site
3. Raw water quality at that point over wet and dry seasons
4. The treatment train and its losses for each use
5. The cooling cycles and reuse the design will actually run
6. The drought and outage terms, and the on-site storage you need
7. The wastewater path, its permit and the limits it puts on the rest

This is general education. It draws on CWA's public site and TCEQ's drought plan rule. CWA's contract terms are set between CWA and each customer, and we could not find a standard contract published online. Confirm terms with CWA and your counsel before relying on any of them.

Frequently asked questions

Does CWA deliver treated water?

Its site describes untreated surface water for its city, industrial and agricultural customers, though its facility list also includes the Red Bluff Water Treatment Plant. Under a raw water contract, an industrial user treats the water for each use itself.

What counties does CWA serve?

CWA operates in Harris, Chambers and Liberty Counties.

Is cooling water reuse worth studying, or are the savings usually small?

It is worth a site-specific study. Higher cycles of concentration cut both makeup and blowdown, but the raw water's chemistry and your discharge limits decide how far you can go.

I'm the project engineer on a new Ship Channel unit and our process design isn't final. How do we ask for a contract quantity without overbuying?

Build a water balance by use from the current design, with ranges for the open items. Ask CWA how the contract handles a later increase, then size the first quantity to the firm design plus a defined path to more.

I manage utilities at an existing plant planning an expansion in Harris County. What do we check first?

Check whether the current contract, delivery point and raw water line have room for the new demand. Then check whether the treatment train and wastewater permit do too. Any one of the three can set your schedule.

Related resources

• Wastewater Engineering for Houston’s Coastal Industrial Zone: TPDES vs. TCEQ Underground Injection in Harris and Galveston Counties
• Industrial TPDES vs. TLAP: Which Wastewater Permit Path Fits Your Texas Facility?
• Groundwater Reduction Plans: What the Harris Galveston Subsidence District Requires Before You Drill a Well
• Data Center Water Supply in Texas: How to Build a Water Plan That Holds Up

Sizing raw water and wastewater for a Ship Channel facility?

We build the water balance, the treatment and the discharge path together, so the contract quantity matches the plant you will actually run.

We specialize in:

• Industrial water balances and supply planning
• Raw water and process water treatment design
• Industrial wastewater treatment and TPDES permitting
• Water reuse evaluation
• Site civil engineering for industrial sites
• Construction administration

Modern Engineering Solutions, McKinney, Texas. Contact: (214) 833-6748 or mod-eng.com