Developer Accused of Not Curbing RunoffPollution: O.C. group says firm building luxury homes on former oil field is letting tainted water flow into river.

A local environmental group is accusing a developer of allowing dirty runoff and other pollutants to flow from a former Yorba Linda oil field into a river that leads to the coast.

Orange County CoastKeeper’s complaint states that Toll Bros. is violating the federal Clean Water Act and state regulations by allowing dirty runoff, mud and construction materials to flow from its Vista del Verde project site, where the developer is building luxury homes, into the Santa Ana River.

“We are shocked at the magnitude of violations,” CoastKeeper’s Garry Brown said in a written statement. “According to our consultant, it is the dirtiest construction site he has seen.’

Jim Sattler, a Toll Bros. project manager, said he cannot comment on specific allegations because he has not seen the complaint yet.

“As far as I know, we’ve been adhering to all the requirements,” he said, noting that the company has plans in place to control erosion and storm-water pollution. State water officials who have visited the site have had no complaints, he said.

“We have not been in violation yet and [these accusations] would be news to me,” said Sattler.

Toll Bros., based in Pennsylvania, is one of the largest U.S. home builders.

The 843-acre site, an old oil field that wraps around the newly opened Black Gold Golf Course at the base of the Chino Hills, is being turned into a master-planned community of 2,179 luxury homes. Attached, detached and estate homes will be built over the next two decades, with prices of $400,000 to more than $1 million.

The Newport Beach-based environmental group filed a letter Friday giving 60 days’ notice of its intent to sue, a preliminary move required under the Clean Water Act.

CoastKeeper’s complaint says that the group has videotapes, water samples and photographs revealing that the construction of three subdivisions-Montecito, Fairways and Pinnacle-violated the federal and state water quality laws. The projects lack controls to stop rainwater and other runoff from coming into contact with construction debris and also lack measures that would keep the contaminated runoff from flowing off the construction site, the complaint states. Erosion has not been minimized, creating sediment-laden runoff, according to the complaint.

If the group’s concerns are not resolved within 60 days, it will file a federal lawsuit against the developer, Brown said.

The Santa Ana River flows to the ocean in Huntington Beach.

A similar CoastKeeper suit against the Irvine Co. resulted in major modifications to part of its Newport Coast development. Those changes stemmed the flow of polluted runoff into the ocean. In exchange for enhanced protection and monitoring, the environmental group dropped its Clean Water Act lawsuit against the developer and its appeals of state and federal decisions over a 635-home Crystal Cove project. The development is above state-protected waters that serve as a dolphin birthing ground.