Economic Impact: Increased Water Costs from Wastewater Discharge 

Overview

Wastewater discharge into Canyon Lake’s watershed doesn’t just threaten water quality — it threatens household water affordability. When lake conditions deteriorate, the Park Shores Surface Water Treatment Plant (operated by Texas Water Company) faces higher treatment costs, emergency maintenance, and infrastructure strain. These costs ultimately flow downstream to customers in the form of higher monthly water bills.

The Canyon Ranch wastewater permit allows effluent containing 100× more phosphorus than Canyon Lake’s baseline to enter Devils Hollow, which flows directly toward the Park Shores intake screens. Elevated nutrients accelerate biological growth, including zebra mussels — the same invasive species that caused a major water‑supply emergency in 2019.

Understanding that event is essential to understanding the economic risk Canyon Ranch poses.

The 2019 Zebra Mussel Crisis: A Case Study in Costly Infrastructure Failure

Infrastructure Failure

In July 2019, zebra mussels migrated deep inside the raw‑water intake structure at Park Shores and completely encrusted the massive pumps that move water out of the lake. Microscopic larvae slipped past protective screens and colonized the interior of the intake pipes.

Operations managers described the blockage as acting “like plaque in an artery.”

Treatment Plant Cut in Half

The biological blockage restricted water flow so severely that the plant’s total water‑production capacity dropped by 50%. With half the normal water volume available, the system could not meet demand.

Emergency Shutdown

On July 24, 2019, the water company pulled its primary intake pipes out of the lake after noticing a sudden drop in water‑production capacity. Inside, they found pumps completely encrusted with zebra mussels.

The plant had to be temporarily shut down, cutting normal operating capacity by more than half.

Emergency Water Shortages

To prevent the system from running completely dry, Texas Water Company issued emergency indoor‑use‑only restrictions for roughly 8,000 customers across Canyon Lake, Spring Branch, Bulverde, and Blanco.

Commercial diving teams were deployed July 26–28, 2019, to physically scrape zebra mussels off the equipment underwater.

Why Canyon Ranch’s Effluent Increases This Risk

The Canyon Ranch wastewater permit allows effluent containing 1.0 mg/L phosphorus — compared to Canyon Lake’s baseline of 0.01 mg/L.

Phosphorus accelerates:

• algae growth

• biofilm formation

• zebra mussel reproduction

• lakebed colonization

• clogging of intake screens and pumps

Because Canyon Lake flows west → east, any high‑phosphorus effluent entering Devils Hollow will travel directly along the northern shoreline toward the Park Shores intake screens.

This creates a direct nutrient‑delivery pathway to the intake infrastructure.

How Higher Treatment Costs Become Higher Household Bills

When intake screens, pumps, and raw‑water pipes are fouled by biological growth, the water company must:

• hire commercial divers

• perform emergency underwater scraping

• replace damaged intake components

• increase chemical treatment

• flush and disinfect raw‑water lines

• upgrade filtration systems

• invest in zebra‑mussel mitigation technologies

• increase labor and maintenance hours

These costs are not absorbed by the utility — they are passed on to customers through:

• rate increases

• infrastructure surcharges

• emergency maintenance fees

• long‑term capital‑improvement charges

The 2019 zebra‑mussel event resulted in significant operational costs, and future events triggered by nutrient‑rich wastewater will be even more expensive.

Why Costs Will Rise After the Canyon Ranch Wastewater Treatment Plant Becomes Operational

Once Canyon Ranch begins discharging:

• phosphorus levels in Devils Hollow will increase

• nutrient‑rich water will flow directly toward the intake

• zebra mussel reproduction will accelerate

• biofouling will increase

• intake screens will clog more frequently

• pumps will require more maintenance

• treatment chemicals will increase

• filtration stages may need upgrading

• emergency responses will become more common

Every one of these factors increases the cost of producing drinking water.

And every one of those costs ultimately appears on monthly water bills.

Long‑Term Economic Consequences

Residents should expect:

• higher monthly water bills

• more frequent emergency restrictions

• increased infrastructure surcharges

• higher long‑term capital‑improvement costs

• greater vulnerability to supply interruptions

This is not speculation — it is the documented pattern seen in lakes across Texas where wastewater discharge and zebra mussels coexist.

Why This Matters

Canyon Lake is not just a recreational resource — it is the drinking‑water source for thousands of households. Wastewater discharge upstream of the intake screens creates a direct economic burden on families, businesses, and communities.

Protecting Canyon Lake’s water quality is not only an environmental issue — it is a household affordability issue.

Take Action

Canyon Lake’s drinking‑water infrastructure has already suffered a major failure once.

With Canyon Ranch’s high‑phosphorus discharge aimed directly at the Park Shores intake screens, the risk of another costly shutdown increases — and so will household water bills.

You can help protect our water supply and keep costs down:

• Ask TCEQ to evaluate nutrient loading impacts from Canyon Ranch

• Request that Texas Water Company assess intake vulnerability

• Support stronger watershed protections for Canyon Lake

• Share this page with neighbors and local officials

• Attend public meetings on regional water supply and infrastructure

Protecting Canyon Lake’s water quality protects your wallet, your water, and your community.