California regulators on Wednesday released a revised set of informal draft rules affecting underground injection control (UIC) wells, an effort that has grown more complex after last year’s methane leak at Southern California Gas Co.’s Aliso Canyon underground storage facility.

The state’s Department of Conservation (DOC), which includes the Division of Oil, Gas and Geothermal Resources (DOGGR), has yet another information draft of rules that are supposed to “modernize and improve” regulations governing the use of water and steam in the production of oil and natural gas, along with the disposal of water generated during production.

Once the informal public comment process is completed, DOGGR expects to begin a formal review process later this year, according to state officials.

Based on the state’s geology, California oil/gas drilling yields far more water than fuel: 205.3 million bbls of oil in 2014 yielded 3.3 billion bbls of water. The naturally brackish produced water can’t be used for human consumption without being treated. Typically, the water is injected back into the reservoir from which it came to provide enhanced oil recovery (EOR) or to maintain reservoir pressure to prevent subsidence at the surface around wells.

DOGGR regulates wells that inject superheated steam, water or other fluids into formations to extract minerals under the UIC program, which ultimately is monitored by the U.S. Environmental Protection Agency (EPA).

Early last year, DOC and DOGGR opened the public comment period for proposed rules and added rules for underground gas storage safety as the Aliso Canyon leak still raged.

In September, a California Superior Court judge in Alameda County upheld the state’s program for UIC wells, which had come under criticism the past two years. Judge George Hernandez found that DOGGR did not violate agreements with the EPA that allow the state to administer UIC programs to protect drinking water aquifers.

Refining the earlier restrictions and protections for the UIC wells, the latest draft added several elements, including:

The public comment period for the draft regulations will run through May 26, and a public workshop will be held on May 24 in Bakersfield, CA.

“Wells that inject super-heated steam, water, or other fluids into formations to extract hydrocarbons minerals also are regulated by DOGGR. And that program is further regulated by federal EPA,” a DOGGR spokesperson said.

“We want to make sure that we get these regulations right so we’re being meticulous, thoughtful, and thorough in our approach,” said state Oil/Gas Supervisor Ken Harris. “These regulations, combined with an aggressive regulatory approach, will help ensure protection of the state’s precious ground water.”