When rain falls on California shopping centers and warehouses, the water runs off parking lots carrying metal dust and chemicals from vehicle tires and brake pads, oil and grease from engines, and bacteria from trash.
The gunk washes into storm drains and pollutes creeks, rivers and beaches.
Now environmental advocates are pushing state regulators to crack down by requiring stormwater permits — essentially best practices — for businesses that haven’t been held accountable for their polluted runoff.
“Commercial properties right now are not regulated under any stormwater permit,” said Sean Bothwell, executive director of California Coastkeeper Alliance. “Think Costco, think Amazon warehouses. Large places with large parking lots are really what we’re going after.”
Groups that represent the businesses say they are already paying property taxes that in L.A. County include a special tax for cleaning up stormwater, and that imposing new regulations in this way doesn’t make sense.
But California Coastkeeper Alliance and other nonprofit groups submitted petitions to regional water officials across the state this week demanding they begin regulating commercial properties such as big-box stores, auto dealers and industrial parks.
The groups want the State Water Resources Control Board to establish a statewide rule, or permit, for “commercial, industrial and institutional” properties, which also include stadiums, malls and private hospitals.
If the state doesn’t act, Bothwell said, “our waterways will never be safe to fish or swim in, particularly Southern California beaches.”
That’s because a large portion of the pollution fouling waterways comes from these businesses. Bothwell said his group estimates, using methods developed by the federal Environmental Protection Agency, that unregulated businesses are responsible for 30% to 60% of metals like copper and zinc found in waterways, depending on the area. At high concentrations, these are toxic to fish and other animals.
Many Southern California creeks and concrete-lined channels are deemed “impaired” by regulators because pollution levels violate water quality standards.
The way California currently enforces the federal Clean Water Act, the businesses have no obligation to reduce the filthy water that flows into drains, and the costs of cleanup efforts fall to cities and counties, Bothwell said.
Instead, the cities or counties where they are located are regulated. Researchers estimate California cities and counties spend more than $700 million each year on capturing and cleaning up stormwater.
California would be the first in the country to adopt such a statewide standard or permit. In addition to cities, the state already requires stormwater permits for construction sites, roads and certain industrial plants.
Business groups have opposed the proposal. John Myers, a spokesperson for the California Chamber of Commerce, noted that the effort to mandate stormwater permits has been discussed for several years in L.A. County after environmental groups won a favorable court ruling. “Simply choosing to use that effort as a template for other diverse regions, without a careful analysis of benefits and costs, could have major impacts on California’s economy,” he said.
The Los Angeles County Business Federation, or BizFed, raised similar concerns.
“Everyone wants cleaner waterways. However, this proposal simply isn’t ready for prime time,” said Mike Lewis, BizFed’s water co-chair.
As written, the proposal “hits existing property owners with retroactive costs while simultaneously ignoring the stormwater taxes they’ve been paying in good faith for years,” Lewis said in an email. “This seems less like environmental policy and more like a penalty. There are better, fairer ways to clean up stormwater.”
If there were a statewide measure for commercial businesses, many would probably have to build retention ponds or swales to filter out contaminants before water percolates underground. Or they could pay an annual fee, helping to fund local stormwater projects that cities need.
The money collected from companies, Bothwell said, would be used for building wetlands, water-absorbing parks and other green spaces next to parking lots — which help clean runoff instead of letting it run into storm drains.
At the same time, Southern California cities have been investing in projects to capture stormwater and recharge groundwater as they seek to rely less on water imported from Northern California and the Colorado River.
Unless the state acts, contaminated water will continue running off businesses’ parking lots into drains, adding to the “toxic soup” in Southern California waterways, said Bruce Reznik, executive director of Los Angeles Waterkeeper.
California Coastkeeper Alliance and a coalition of local Waterkeeper groups submitted the petitions to regional boards in the Inland Empire, San Diego, the Bay Area, the Central Coast, the North Coast and the Sacramento Valley.
They invoked a provision of the Clean Water Act that authorizes states to require additional permits on a case-by-case basis.
L.A. Waterkeeper and other environmental groups successfully used the same provision to convince the EPA in 2024 to require permits for businesses near the polluted Dominguez Channel and Los Cerritos Channel in L.A. County. State regulators are preparing to issue those permits.
The regional water boards received the new petitions and will consider them, said Ailene Voisin, a spokesperson.
In 2022,Gov. Gavin Newsom vetoed legislation that would have required stormwater permits for many businesses statewide. In 2025, a similar bill faced opposition and died in the Legislature.
The post Polluted rain runoff from big box parking lots could see a crackdown appeared first on Los Angeles Times.
