By most accounts, the Edwards Aquifer contains some of the cleanest water around.
The Edwards Aquifer Authority has made it their task to keep it that way, but it is becoming increasingly difficult.
The difficulty lies with old, abandoned wells.
"Some of them are 70 or 80 years old,” said Roger Andrade, water well evaluation supervisor for the Edwards Aquifer Authority.
One abandoned well, believed to be constructed in the 1930s, lies in the middle of Breckenridge Park. Old and forgotten, these wells are open conduits for contamination to make into the clean water below.
As for what pollutants make into the wells: "Whatever is in the storm runoff and that's just about everything -- oil and gas, manure,” said Andrade.
Even worse, one abandoned San Antonio well is thought to serve as a toilet for nearby homeless people.
According to the Edwards Aquifer Authority, there are hundreds of known uncapped and unplugged wells in San Antonio.
In the case of the Brackenridge Park well, it lies on city property. The EAA said the city has been a willing partner when it comes to plugging abandoned wells.
"We have worked together and gone through the process of either getting them capped or plugged,” said Bill Pennell, with San Antonio Parks and Recreation.
State law does prohibit against abandoned wells.
“It has to be a well in use. It has to be properly maintained and not deteriorated,” said Andrade.
The EAA said private property owners had been less compliant when it comes to footing the bill for capping or plugging a well.
The EAA has offered to help those land owners, in hopes of keeping the aquifer free of contamination.