An ongoing, multilateral debate between the city of Dripping Springs and numerous environmental groups has slowed to a halt after the municipality’s highly contested discharge permit was sent to be reviewed by an administrative law judge last month.

The hearing, which will likely be settled in the next six months, will decide whether the City of Dripping Springs’ Texas Pollutant Discharge Permit (TPDES); which will allow the city to dump up to 995,000 gallons of treated wastewater effluent into Onion Creek; will cause significant environmental damage.

Even if the court rules that the permit is harmful, ultimately the Texas Commission on Environmental Quality (TCEQ) has the final word; the outcome of the hearing will only be a recommendation, Chris Herrington, the supervising engineer at the City of Austin Watershed Protection Department said.

The battle over the Dripping Springs permit began in 2015 when the municipality first applied for it. Environmental groups like the Save Barton Creek Association have resisted the permit on the grounds that the wastewater dumped into Onion Creek could contaminate the “environmentally sensitive” Edwards aquifer, an artesian aquifer that supplies water to nearly two million people in south central Texas.

Herrington agrees that it would.

“[The permit] would cause eutrophication or degradation of Onion Creek.” Herrington said. “Everything you flush down the drain or the sink… eventually ends up in our wastewater,”

By everything, he means anything from toothpaste to pharmaceutical drugs and household chemicals that are improperly disposed of. The trouble, Herrington says, is that even after two stages of water treatment, and a suitable rating by the EPA for discharge back into the environment, there are still tiny traces of drugs in the water, many of which haven’t been evaluated by the EPA.

Another major problem, which environmental groups alerted Dripping Springs to after the city called for public comment ,is eutrophication. This occurs when there are excessive levels of nutrients like nitrogen in the water, resulting in algal blooms. These blooms are dangerous for waterways because they lead to hypoxia, or a lack of dissolved oxygen in the water, which slowly kills fish and other organisms and leads to dead zones.

Besides depleting the natural ecosystem, Herrington says, an excess of treated effluent could lead to aesthetic damage, changing the water’s color and clarity, and also potential altering taste and smell, deterring visitors from using the water recreationally.

Herrington said that Dripping Springs’ permit application is “not something being driven by an immediate need.”

“They have a lot of capacity at their current treatment plant,” Herrington said. “This is really about Dripping Springs using their permit for revenue.”

Though this is legal, and although, according to Herrington, the City of Dripping Springs has made verbal agreements with the City of Austin not to abuse their permit, he still worries about the power the permit will give the municipality and the precedent it would set for other cities.

But fighting the permit is a risky gamble for Austin. Herrington says that the lawyer the City of Austin hires has to prove “significant harm to the environment,” a “pretty high bar,” he adds. The city has to pay the legal consultation for as long as it takes to make its case, and even if it wins, it isn’t a guarantee Dripping Springs will change its permit.

“Now we’re arguing with the EPA,” Herrington says. “It’s definitely an uphill battle.”