At approximately 1,000 acres in size, the A.R. Wilson Quarry in Aromas, California, is the largest crushed rock quarry west of the Mississippi River. The quarry is owned and operated by Granite Rock Company (commonly known as “Graniterock”), a private construction materials and contracting company that bills itself as one of the leading suppliers of high-quality aggregate, sand, concrete, recycled aggregate, and hot mix asphalt in the Monterey and San Francisco Bay Areas.
During the dry months of the year, Graniterock’s wastewater is contained in a closed-loop wastewater treatment system. But during the rainy season, the additional water inflows exceed the system’s capacity and Graniterock discharges its pollutant-laden overflow into the nearby Pajaro River. Based on the facility’s discharge monitoring reports, NELC attorneys determined that Graniterock has been habitually violating its Clean Water Act permit limits for pollutants such as aluminum, iron, molybdenum, and total dissolved solids during these rainy months. Over the last decade, Graniterock has violated these same permits limits over and over again, repeatedly paying the California mandatory minimum penalty amount without actually addressing the underlying cause of the violations.
Graniterock’s pollution is of particular concern because the quarry sits along the Pajaro River, a beloved recreation area that is home to the threatened South-Central California Coast Steelhead. Steelhead are a species of rainbow trout that migrate to the ocean to mature. When it comes time to spawn, steelhead leave the ocean and swim upstream to their freshwater breeding grounds. But in recent years, habitat change due to human development and pollution have made it increasingly difficult for steelhead to reach their breeding grounds. South-Central California Coast steelhead, which have been listed as a threatened species under the Endangered Species Act since 1997, will likely be extinct in within 50 years without concerted efforts to restore access to their historical habitats.
Each year between January and May, just as the rainy season is overwhelming Graniterock’s wastewater treatment system, steelhead migrate up the Pajaro River. As they do so, they are exposed to the harmful pollutants in Graniterock’s wastewater, which can have detrimental effects on their health and reproductive success.
On April 15, 2026, NELC attorneys filed a federal citizen suit against Graniterock on behalf of the non-profit groups Environment California and California Sportfishing Protection Alliance. The groups allege that the company violated the Clean Water Act for more than 1,000 days in the last five years, and that Graniterock has failed to conduct the wastewater monitoring required by its permit, leaving critical gaps in its discharge data. The suit aims to bring Graniterock into compliance with its effluent limits and monitoring obligations, and in doing so safeguard the Pajaro River and its inhabitants.