In early December, a Dripping Springs resident was alarmed when pink water filled her sink. After calling a plumber, it was discovered the discoloration was a result of a nontoxic dye test conducted by the Hays Trinity Groundwater Conservation District, the Barton Springs Edwards Aquifer Conservation District, the city of Austin and the Meadows Center for Water and the Environment as part of an unrelated study to observe how surface water in Onion Creek recharges the Trinity Aquifer.
"That homeowner is over a mile away from the injection site," said Richard Beggs, board member with Protect Our Water. "It hit her home in 24 hours and ran for multiple weeks."
Dripping Springs Mayor Todd Purcell responded Monday evening with a statement on the city's blog. While the results of the dye study are unsettling, he said, no public wells were impacted, and therefore definitive proof of whether wastewater discharge would contaminate public drinking water has yet to be found.
"Even if this study ends up definitively showing connectivity [between Onion Creek and groundwater or wells], we have no information that would suggest that any discharge of wastewater effluent would negatively affect wells or water that is currently suitable for drinking," he said.
Since 2015, local environmental groups like Protect Our Water have voiced opposition toward a draft permit currently under review by the Texas Commission on Environmental Quality that would allow the city of Dripping Springs to discharge almost a million gallons of wastewater effluent into Onion Creek per day.
“There are more than 200 water supply wells near or downstream from the proposed sewage effluent discharge within a mile of Onion Creek," said environmental engineer Lauren Ross in a Protect Our Water news release. "Four of these are public supply wells. If treated sewage is discharged into Onion Creek, the only water supply for hundreds of homes is at risk.”
The city has maintained its permit contains "stringent effluent limits" and that it is committed to 80 percent reuse of the wastewater for irrigation purposes.
"Between our irrigation land and reuse agreements, we have 600,000 gallons of the 995,000 gallons per day permit accounted for, and there is already reuse demand for the remaining 395,000 gallons per day," Purcell's statement said.
Still, Protect Our Water says nothing short of 100 percent reuse is sufficient in ensuring the safety of residents whose drinking water could be compromised by the discharge.
"We have repeatedly asked the city to provide scientific due diligence that this is a safe project for our community and they have failed to respond," Beggs said. "We are extremely grateful to start to have really good understanding that there is a connection [between wastewater discharge and area drinking water] and that we have to be careful with the decisions we make."