A pipeline apparently broken by tree roots caused a small sewage spill into the ocean at Dillon Beach Monday, North Marin Water District manager Chris DeGabriel announced today.

“It’s estimated that over 250 gallons of sewage surfaced from a broken pipeline on a steep hillside in the vicinity of Kailua Way,” he said, adding that the leak “was likely caused by tree roots damaging a pipe joint.”

Seen from Elephant Rock, Dillon Beach looks tranquil with Lawson’s Landing resort and the mouth of Tomales Bay in the distance. In the town’s Oceana Marin subdivision, however, a sewage spill caused a bit of a commotion yesterday.

Kailua Way is within the Oceana Marin subdivision, where North Marin operates the sewer system. “District crews responded, and Roto Rooter Sewer Service was dispatched to the area,” DeGabriele reported. “The spill was contained and initial pipe repair made within four hours of the district’s response.

“During that time, raw sewage flowed over land and ultimately into a drainage swale and storm drain that flows to the ocean…. The affected drainage swale and beach has been taped off and signed to keep people away from the area.

“Water samples upstream and downstream from the spill are being tested, and the results will be made available as soon as possible. Cleanup of the sewage discharged onto the area has begun, and the district is pursuing permanent repair of the pipeline.”

DeGabriele said a Dillon Beach resident first alerted North Marin to the spill and that “Marin County Health Department, the North Coast Regional Water Quality Control Board, and California Department of Fish and Game were notified of the incident.”

North Marin’s quick notification of regulatory agencies contrasts with the Sewerage Agency of Southern Marin’s slowness to report two sewage spills totaling 5.2 million gallons into Richardson Bay, an arm of San Francisco Bay, on Jan. 25 and 31.