"We're currently determining whether this was a stormwater or trade waste drain. We're also looking into the environmental effect of tipping the alcohol down a stormwater drain," the agency said.
"Once we've figured out the type of drain, and the effect, we will decide if there is anything else we need to do."
However, police say the booze went down a vehicle wash drain, not a storm water drain.
"Commercial car and truck wash facilities are required to have a trade waste consent and an approved treatment system for disposal of wash water to the wastewater system," a police spokeswoman said.
"So essentially, the wash water goes into the sewerage system, not the storm water drains, and therefore has no impact on waterways."
She said Environment Canterbury had received lots of calls from members of the public concerned about the potential impact on storm water drains and local waterways after a story on the disposal was published yesterday.
"They have therefore sent an inspector to the site to confirm that the disposal method was appropriate."