Environmental groups also contend the new rules fail to set standards for how groundwater samples are collected and tested, and will allow drilling operators to "cherry pick" which water sources to sample.
The Colorado Oil & Gas Association supported building on a voluntary groundwater monitoring program that began in January.
Oil and gas drilling accounts for nearly 44,000 jobs in Colorado and brought in $208 million in severance taxes last year. However, residents along the Front Range have expressed concerns about potential health effects from drilling as activity moves closer and closer to more populated areas.
Industry groups had sought to limit testimony at the hearing from people who live near drilling sites, saying in part that their comments on their health problems weren't based on medical expertise. The commission, however, decided to allow the testimony.
Gov. John Hickenlooper has called for a consistent set of state rules, so companies do not face conflicting local regulations that could drive them to other states.
Colorado Oil and Gas Conservation Commission: http://cogcc.state.co.us