How clean should San Luis Obispo’s treated wastewater have to be before it’s discharged into San Luis Obispo Creek?
The Central Coast Regional Water Quality Control Board says the water should be clean enough to drink, especially since the creek is officially designated for use as domestic or municipal water supply.
An Avila Valley water company agrees, saying its shallow wells near the creek downstream from SLO’s wastewater plant supply 600 homes and businesses in the Avila Valley with clean drinking water. The city of SLO “curiously and improperly” ignores that fact, according to a letter from the San Miguelito Mutual Water Company.
But SLO officials argue that removing more pollutants would cost city residents “tens of millions of dollars,” and is unnecessary. They’ve asked the water board to remove the creek’s designation as a water supply, which would cancel the requirement that nitrates and two toxic pollutants known as trihalomethanes must be at levels low enough to be safe for human health.
The underlying issue is whether the Avila Valley drinking-water wells are “under the influence” of—in other words, connected with—surface water in the creek. Officials from the San Miguelito Water Company state in their letter that “any independent engineer not hired by the city would find such a connection.”
Water board members were scheduled to take action on the city’s request at their May 5 meeting in SLO. But city officials are now asking to delay any decision until they can study just how connected the creek water is to the groundwater.