ORANGE COUNTY, CA-The environmental effects of storm-water runoff have become an immediate concern for developers of projects in San Diego and will soon become equally concerning to developers of projects in South Orange and Riverside counties, thanks to stricter permit regulations for storm-water and dry-weather runoff, known as the MS4 Permit, which were approved this month. The requirements will take place in San Diego immediately, in Southern Orange County starting in December 2014 and in Riverside County in November 2015.

Kathryn Horning, an attorney with law firm Allen Matkins, tells that the legislation imposes restrictions on new and existing developments that have never been imposed before now, and owners and developers need to be aware of how it will impact them. “The requirements that the City is going to have to meet are going to be filled by owners and developers,” says Horning. “The San Diego Regional Water Quality Control Board is focusing on storm-water pollution, and one of the board members has said that storm-water is one of its top three priorities over the next three years, so they’re trying to step up on this.”

The board approved a Regional MS4 Permit that will regulate both storm-water and non-storm-water discharges into the region’s storm-water conveyance facilities, which carry runoff to inland surface waters, bays, estuaries and coastal waters, Horning explained in a legal alert. “The new MS4 Permit contains tough numeric limits for storm-water pollutants. Although the permit directly regulates cities, counties and special districts [that] own and operate large MS4s, it requires these permittees to impose the permit’s requirements on development projects, construction sites and existing development (including commercial, industrial, municipal and residential areas) through statutes ordinances, permit conditions, contracts, orders and other similar means.”

Horning added that developers, contractors and existing facility owners will therefore be impacted as permittees attempt to comply with the permit’s requirements. “In particular, the permit emphasizes on-site retention and treatment of surface-water runoff, as well as practices to protect and return water courses to a more natural condition.”

Developers and owners can implement a number of low-impact development practices in order to be in compliance with the new regulations, Horning tells They can set up swales or certain types of landscaping where the storm-water is infiltrated into the soil itself or into the landscaping so that pollutants would not go directly into storm drains. Rain barrels where rain is captured and used for future irrigation purposes are another option, as is biofiltration, which may work better in non-urban areas.

“One interesting aspect is that cities may be able to allow developers to fund on-site programs,” says Horning. “Treatment methods aren’t cheap, and these regulations will impact developers who need to find space to implement requirements and practices to treat or retain storm water.”

The most dramatic impact of the regulations will be felt in priority development projects where there is 10,000-plus square feet of impervious surface, hillside projects or auto-repair projects.

No specific steps need to be taken until the city begins to impose regulations, says Horning. At that point, developers and owners can find out what the cities and counties are requiring developers to do in their specific sites, since there are different requirements for different types of sites.

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