NORMAN — Groundwater supplies nearly 40 percent of all water used in Oklahoma, according to John Harrington, director of Water Resources, Association of Central Oklahoma Governments, but people don’t always know whether that water is drinkable before they drill.
The Oklahoma Corporation Commission has had many complaints of water well pollution over the past two decades in and near oilfields. The oilfields that most often create the problem are older fields with activity initiated before 1980, Harrington reported to the Norman City Council at its study session on Tuesday evening.
Nowadays, Oklahoma knows how to prevent saltwater problems associated with oil rigs and natural gas wells, but some old wells are impacting modern water wells.
“We are detecting this saltwater with electrical imaging techniques,” Harrington said of identifying contamination of private water wells.
As many as 295,000 Oklahomans have private water wells and 73 percent of all agricultural irrigation comes from groundwater, Harrington reported.
Recently, a “fairly new gated community in Northwest Oklahoma City” had problems with salt contamination in private water wells, Harrington said.
When a domestic well is drilled, if the piping does not have enough casing to protect it, contamination can occur from oilfield salt water in the shale. That well can lead to cross contamination of the aquifer.
Harrington said requiring casing to run deeper could protect domestic water wells from contamination. Unused water wells should also be “drilled out and plugged to prevent the spread of more contaminants down into the aquifer,” Harrington said.
In an effort to provide more information for well drillers, the Oklahoma Corporation Commission has been mapping old oil wells on Oklahoma Aquifers.
Additionally, water watchdogs want to require protective casing for a depth of at least 30 feet.
“We are making a proposal to the water resources board to amend the drilling standards,” Harrington said.
A primary amendment would add the requirement for deeper casing for water wells.